- Open Access
Oleoylethanolamide attenuates cocaine-primed reinstatement and alters dopaminergic gene expression in the striatum
Behavioral and Brain Functions volume 19, Article number: 8 (2023)
The lipid oleoylethanolamide (OEA) has been shown to affect reward-related behavior. However, there is limited experimental evidence about the specific neurotransmission systems OEA may be affecting to exert this modulatory effect. The aim of this study was to evaluate the effects of OEA on the rewarding properties of cocaine and relapse-related gene expression in the striatum and hippocampus. For this purpose, we evaluated male OF1 mice on a cocaine-induced CPP procedure (10 mg/kg) and after the corresponding extinction sessions, we tested drug-induced reinstatement. The effects of OEA (10 mg/kg, i.p.) were evaluated at three different timepoints: (1) Before each cocaine conditioning session (OEA-C), (2) Before extinction sessions (OEA-EXT) and (3) Before the reinstatement test (OEA-REINST). Furthermore, gene expression changes in dopamine receptor D1 gene, dopamine receptor D2 gene, opioid receptor µ, cannabinoid receptor 1, in the striatum and hippocampus were analyzed by qRT-PCR. The results obtained in the study showed that OEA administration did not affect cocaine CPP acquisition. However, mice receiving different OEA treatment schedules (OEA-C, OEA-EXT and OEA-REINST) failed to display drug-induced reinstatement. Interestingly, the administration of OEA blocked the increase of dopamine receptor gene D1 in the striatum and hippocampus caused by cocaine exposure. In addition, OEA-treated mice exhibited reduced striatal dopamine receptor gene D2 and cannabinoid receptor 1. Together, these findings suggest that OEA may be a promising pharmacological agent in the treatment of cocaine use disorder.
Among psychostimulants, cocaine is the most abused substance worldwide with an ongoing increasing tendency over the past decade . Epidemiological studies estimate that there are approximately 1.3 million people diagnosed with cocaine use disorder (CUD) in the US. Although there has been promising progress in the development of effective treatments, to date, no pharmacological therapy has been approved for CUD .
One of the major hallmarks of substance use disorder, including CUD, is a high risk of relapse following treatment, even after long periods of abstinence . Vulnerability to relapse is markedly increased when a recovering individual experiences high levels of stress, encounters contextual cues associated with prior drug use oringests a low dose of the drug . In the laboratory, the mechanisms that underlie the persistent risk of relapse can be studied using rodent models of reinstatement. In the conditioned place preference paradigm (CPP), the reinstatement test is performed after the extinction of the drug-reinforced place preference. One of the strategies used to reinstate drug seeking is drug-priming with a small dose of the drug. This approach has been shown to be very useful in finding potential pharmacological agents that reduce cocaine relapse risk [5, 6].
Research has identified multiple neuronal mechanisms that contribute to the lasting vulnerability to relapse into cocaine use. The main effect of cocaine intake is an acute inhibition of monoamine reuptake in the nucleus accumbens, a key brain region of the mesolimbic pathway . It is now established that repeated cocaine exposure induces long-term neuronal adaptations in the mesolimbic system, which contribute to persistent drug seeking, craving and relapse . Indeed, this dopaminergic signaling is necessary for a stressful stimulus, contextual cues, or cocaine priming to induce reinstatement behavior . Mounting evidence has shown that other non-dopaminergic systems are involved in relapse vulnerability. Recently, the endocannabinoid system has been revealed as an important modulator of dopaminergic signaling and cocaine reward [10,11,12,13]. Studies with rodents have shown that administration of cannabinoid antagonists results in diminished cocaine reward and attenuated cocaine-primed and cue-induced reinstatement of cocaine-seeking behavior [14, 15]. In parallel, numerous studies have highlighted the involvement of the opioid system in drug relapse. More specifically, several lines of research indicate a crucial role for the µ opioid receptor in the neurocircuitry that mediates stress-induced reinstatement of cocaine seeking behavior [16, 17].
Research has shown that active compounds that target the aforementioned brain systems can alleviate the negative outcomes of cocaine use and thus, reduce relapse susceptibility. In the past years, there has been increasing evidence showing that lipid-based signaling molecules are important regulators of reward and drug-seeking behavior . Oleoylethanolamide (OEA) is a lipid belonging to the N-acetylethanolamine family (NAEs) present in most mammals . In humans, OEA is synthesized by cells in the small intestine and adipose tissue. The vagal afferent fibers allow for communication from the intestine to the CNS . In the brain, OEA has neuromodulatory effects by binding to nuclear receptor peroxisome proliferator-activated receptor alpha (PPAR-α) and the capsaicin receptor transient receptor potential cation channel subfamily V member 1 (TRPV1) [21, 22]. Anatomical studies have shown that PPAR-α and TRPV1 are widely expressed in the mesolimbic system, including the striatum and hippocampus, which are known to be brain areas involved in the reinstatement of drug-seeking behavior [23,24,25,26].
Recently, preclinical studies have found that OEA also modulates reward-related behavior including cocaine-induced behaviors [18, 27, 28, 30]. Bilbao and co-workers  showed that OEA administration reduced psychomotor activation induced by cocaine and blocked cocaine CPP. Similarly, a recent study has found that OEA treatment blocks stress-induced cocaine CPP . Furthermore, cocaine self-administration has been shown to affect OEA levels in limbic areas such as the dorsal striatum [33, 34].
The available evidence on the neuronal pathways underlying the modulatory effect of OEA on cocaine reward is limited and scattered. To exert these various effects on cocaine-related behavior OEA may be targeting multiple brain signaling pathways. Thus, the aim of this study was to evaluate the effects of OEA on cocaine reward by using the CPP paradigm. In addition, gene expression analyses were carried out by quantitative real-time polymerase chain reaction (qRT-PCR) to evaluate changes in relevant signaling targets involved in cocaine relapse, including dopamine receptor D1 gene (DrD1), dopamine receptor D2 gene (DrD2), opioid receptor µ (OPRM1), and cannabinoid receptor 1 (CNR1). We analyzed brain structures affected in the pathophysiology of drug abuse, i.e., the striatum, which regulates reward processing, and the hippocampus, which plays a key role in memory formation and learning.
Methods and materials
Animals and experimental design
OF1-strain adult male mice (n = 56) were used in this study (Charles River, France). On arrival, mice were housed in groups of four in plastic cages under constant temperature under a reverse 12-h light/dark cycle and water and food available ad libitum, except during behavioral testing. All animals acclimated to the environment for one week before the experimental procedure.
Mice were divided into different experimental groups according to different OEA treatment schedules: (1) Control CTRL (2) received OEA i.p (10 mg/kg) before each cocaine conditioning session (OEA-C), (3) before each extinction sessions (OEA-EXT) and (4) before the reinstatement test (OEA-REINST), (see Fig. 1). All procedures were conducted in compliance with the guidelines of the European Council Directive 2010/63/EU regulating animal research and were approved by the local ethics committees of the University of Valencia.
OEA (10 mg/kg, i.p.; synthesized as described in ) was dissolved in 5% Tween 80 in saline and injected 10 min before the corresponding test. The doses were chosen according to previous studies in rodents reporting effective therapeutic effects [35,36,37,38].
For CPP, animals were injected with 10 mg/kg cocaine hydrochloride (Laboratorios Alcaliber S.A., Madrid, Spain) diluted in saline (NaCl 0.9%) and adjusted to a volume of 0.01 ml/g of weight.
Conditioning place preference (CPP)
For place conditioning, we employed Plexiglas boxes with equally sized compartments (30.7 cm length x 31.5 cm width x 34.5 cm height) separated by a gray central area. The compartments had different colored walls (black or white) and distinct floor textures (fine grid in the black compartment and wide grip in the white one). Four infrared light beams in each compartment of the box and six in the central area allowed the recording of the position of the animal and the number of crossings from one compartment to the other. The equipment was controlled by two IBM PC computers using MONPRE 2Z software (CIBERTEC S.A., Spain.).
10 mg/kg cocaine-induced CPP
A three-stage CPP procedure consisting of acquisition, extinction and reinstatement was performed. The CPP acquisition was performed as described previously  and consisted of three phases (see Fig. 1). During the first phase (Pre-Conditioning; Pre-C), mice were allowed access to both compartments of the apparatus for 15 min (900 s) per day for 3 days. On day 3, the time spent in each compartment over a 900-s period was recorded, and animals showing a strong unconditioned aversion (less than 30% of the time) or preference (more than 70% of the time) for any compartment were excluded from the study (n = 15). After assigning the compartments, no significant differences were detected between the time spent in the drug-paired and vehicle-paired compartments during the pre-conditioning phase. During the second phase (Conditioning), mice received intraperitoneal injections of 1 mg/kg cocaine or saline and confined to alternating sides of the CPP apparatus. For four days, animals received an injection of saline immediately before being confined to the vehicle-paired compartment for 30 min. After an interval of 4 h, animals received an injection of cocaine immediately before being confined to the drug-paired compartment for 30 min. Confinement was carried out in both cases by blocking the access that separated the two compartments. On the Post-conditioning testing day and subsequent days, mice were allowed to move freely between sides during a 900-s recording period. For extinction, mice were placed in the CPP apparatus daily and the time spent in each compartment was measured to determine if cocaine-induced preference had disappeared. Although the mean of the group as a whole determined the day on which extinction was considered to have been achieved, preference was considered to be extinguished when a mouse spent 378 s or less in the drug-paired compartment on two consecutive days. We chose this time based on the values of all the Pre-C tests performed in the study (mean = 368 s). When the preference was not extinguished in an animal, it was assigned the number of days required for extinction for the group as a whole. Finally, 24 h after reaching the extinction criterion, mice were challenged with a cocaine injection once, followed by a place preference test (reinstatement test).
Tissue sampling and biochemical analyses
Mice were sacrificed by cervical dislocation. The striatum and hippocampus were precisely dissected out based on the atlas of the Paxinos and Franklin  using a coronal brain matrix. Tissue samples were stored at −80ºC until the qRT-PCR assay was performed.
RNA isolation, reverse transcription, and quantitative RT-PCR
Striata and hippocampi were lysed in 1 mL of Tri-Reagent solution (Sigma-Aldrich, Madrid, Spain) and total RNA was isolated according to the manufacturer’s instructions. Then, the mRNA was reverse-transcribed by the NZY First-Strand cDNA Synthesis Kit (NZYTech, Lda. Genes and Enzymes, Lisbon, Portugal) following the manufacturer’s instructions. Amplification of the target and housekeeping (b-glucuronidase) genes was completed employing the Taqman Gene Expression Master Mix (Thermo Fisher Scientific, Madrid, Spain) in a LightCycler 480 System (Roche Diagnostics, Madrid, Spain). The assay codes of the primers used were Mm02620146 (DrD1), Mm00438545 (DrD2), Mm01188089 (Oprm), Mm01212171 (Cnr1) and Mm00446953 (b-glucuronidase). Data were analyzed using the LightCycler 480 relative quantification software and normalized to the amplification product of b-glucuronidase.
To test for the CPP acquisition, the time spent in the drug-paired compartment was analyzed with a two-way ANOVA with one between-subjects’ variable – Treatment, with four levels (CTRL, OEA-C, OEA-EXT, OEA-REINST) and one within subjects’ variable with two levels, pre- and post-CPP measurement (Pre-C and Post-C). Additionally, a one-way ANOVA was conducted to assess whether the conditioning score (defined as time spent in the drug-paired side minus the time spent in the saline-paired side) was different between groups. Post-hoc comparisons were performed by means of Bonferroni tests.
Extinction and reinstatement values were analyzed by a Student’s t-test and the time required for the preference to be extinguished in each animal was analyzed by means of the Kaplan–Meier test with Breslow (generalized Wilcoxon) comparisons .
The gene expression data were analyzed by a one-way ANOVA with one between variables, Treatment, with two levels (control, OEA-treated). Bonferroni post-hoc tests were also analyzed. In addition, correlation analysis between conditioning scores and gene expression was performed using Pearson’s correlation coefficient (r). Results are expressed as the mean ± SEM, and statistical significance was set at p < 0.05. Statistical analyses were performed using SPSS Statistics v28.
OEA treatment does not block cocaine (10 mg/kg) CPP acquisition but prevents reinstatement
The ANOVA of the CPP data revealed an effect of the variable Days (F (1,51) = 68.238; p < 0.001). Mice in every experimental group developed cocaine-induced CPP, spending more time in the drug-paired compartment during the Post-C test than in the Pre-C test (p < 0.001), (see Fig. 2).
With regards to the time required to extinguish the preference (see Fig. 3), the CTRL group required a mean number of 11.2 sessions, while the OEA-C, OEA-EXT and OEA-REINST groups required only 4, 5 and 6.8 sessions, respectively. The Kaplan-Meier analysis revealed that the CTRL group required significantly more sessions than the OEA-C to extinguish the preference (χ2 = 3.864; p = 0.049).
Reinstatement of drug-seeking behavior after achievement of extinction was evaluated with Student’s t-tests, which showed that reinstatement with a priming dose of 5 mg/kg cocaine was achieved only in the control group (see Fig. 2).
OEA administration altered the relapse-related gene expression in the striatum and hippocampus
OEA-treated mice presented decreased striatal DrD1, DrD2, CNR1 gene expression
For DrD1 and DrD2 gene expression (see Fig. 3a, b), the ANOVA revealed a significant effect of the variable treatment [F(1,30) = 10.898; p < 0.01] and [F(1,30 = 11.007; p < 0.01], respectively. With regards to CNR1 expression, the ANOVA revealed an effect of the variable treatment [F(1,30) = 5.629; p < 0.05] (see Fig. 3d). OEA treatment induced a significant decrease in DrD1, DrD2 and CNR1 gene expression in OEA-treated mice (OEA-C, OEA-EXT and OEA-REINST groups) with respect to the CTRL group.
OEA-treated mice presented decreased hippocampal DrD1 gene expression
For DrD1 gene expression (see Fig. 4a), the ANOVA revealed a significant effect of the variable Treatment [F(1,30 = 6.525; p < 0.05]. OEA treatment significantly decreased DrD1 expression in OEA-treated mice with respect to the CTRL group.
We performed a Pearson correlation between the conditioning score after the Post-C and the reinstatement test and the expression of DrD1, DrD2, OPRM1, and CNR1 in the hippocampus and striatum (See Fig. 5). Although the conditioning score after Post-C test did not show any correlation, we obtained a positive significant Pearson correlation coefficient between the conditioning score of the reinstatement test and the hippocampal expression of DrD1 (r = 0.508, p < 0.003) and a tendency with the expression of CNR1 (r = 0.328, p < 0.067), meaning that a higher place preference in the reinstatement test positively correlates with a higher expression of these gene receptors (see Fig. 6).
Additionally, we also obtained other interesting correlations among the expression of these genes. Expression of DrD1 and DrD2 correlated positively in the striatum (r = 0.908, p < 0.001). Equally, gene expression of CNR1 in the hippocampus correlates positively with OPRM1 (r = 0.500, p < 0.004). However, in the striatum, gene expression of CNR1 correlated positively with DrD2 (r = 0.588, p < 0.001).
In the present work, we explored the effects of the lipid OEA on the reinforcing properties of cocaine using the CPP paradigm. We further supplemented this work using qRT-PCR for characterizing gene expression of four relevant receptors for cocaine reward in the striatum and hippocampus. Our results showed that OEA treatment (10 mg/kg) blocked cocaine-primed reinstatement. In addition, we observed that OEA altered dopaminergic and cannabinoid gene expression. More specifically, decreases in DrD1, DrD2 and CNR1 gene expression levels were detected in the striata of OEA-treated mice compared to those of the CTRL group. In addition, we found a significant decrease in DrD1 gene expression in the hippocampus, but no alterations in other receptors.
Previous studies have observed an attenuating effect of OEA on cocaine reward. In our study, we employed three different administration schedules that differed in timing and number of OEA doses (OEA-C, OEA-EXT and OEA-REINST). Regarding the CPP, we observed that all groups (CTRL, OEA-C, OEA-EXT and OEA-REINST) displayed CPP induced by cocaine (10 mg/kg). A previous report by Bilbao and coworkers  showed that coadministration of OEA with cocaine during conditioning reduced the CPP acquisition at 1 and 5 mg/kg doses. In their study, the highest dose of OEA tested (20 mg/kg) completely abolished cocaine-induced CPP (20 mg/kg). To account for these uneven results, it should be noted that, a higher dose of both OEA and cocaine was used than the one employed in our study.
To our best knowledge, this is the first study exploring the effect of OEA administration on cocaine reinstatement. For this purpose, after a series of extinction sessions, mice underwent a reinstatement test induced by a priming cocaine injection (5 mg/kg i.p). We observed that different OEA administration schedules blocked cocaine-primed reinstatement. Interestingly, this effect did not depend on the number of doses received in each experimental group. Mice in the OEA-C and OEA-EXT groups received 4 and 5 doses of OEA respectively, and the OEA-REINST group received only a single dose. However, it is important to remark that in the case of the OEA-REINST group, OEA administration occurred 10 min before the cocaine priming dose. It is possible that administering OEA prior to the cocaine priming dose results in an equivalent effect achieved with a greater number of non-contingent doses (several weeks and 48 h, respectively). Moreover, we must highlight that the OEA-C and OEA-REINST groups required a lower number of sessions to extinguish the preference than the CTRL group (although only OEA-C reached statistical significance). This shorter extinction process suggests that OEA could affect the association of cocaine with a distinctive environment during the conditioning phase in the OEA-C group or accelerate the generation of new learning during extinction in the OEA-EXT group.
Overall, these results are in agreement with several reports of an attenuating effect of OEA on drug-seeking behavior of other substances. Research conducted on primates and rodents have shown that administration of OEA results in decreased nicotine self-administration and reinstatement . Similarly, a previous study used a pharmacological inhibitor of FAAH, the enzyme that catalyzes the hydrolysis of ethanolamides such as anandamide and OEA, to study its effect on cocaine self-administration . Consistent with our results, they found that inhibition of FAAH did not alter cocaine self-administration, but was able to reduce cocaine-seeking behavior on cue-induced and drug-induced reinstatement tests. Interestingly, it has been recently observed that cocaine-induced relapse results in a potent increase in NAEs levels in the striatum but, parallelly, a decrease in tissue levels of OEA in the nucleus accumbens (NAc), cerebellum and hippocampus .
Given the mounting evidence of neuroprotective effects of OEA on drug-induced brain damage, we characterized its interaction with gene expression of four receptors of relevant systems mediating cocaine reward and reinstatement.
Dopamine transmission in the striatum is crucial for the reinforcing properties of cocaine . Repeated cocaine administration produces multiple molecular and cellular adaptations, including altered expression of dopaminergic receptor genes in the striatum. Both D1 and D2 receptors mediate the reinstatement of cocaine-seeking behavior. D2 receptor activity generally facilitates priming-induced reinstatement , while the use of D2 antagonists diminishes cocaine-primed reinstatement . In the case of D1 receptors, both agonists and antagonists are able to reduce cocaine priming effects [46,47,48]. Given its role in cocaine reward and reinstatement, we hypothesized that OEA may alter dopaminergic signaling. Indeed, our findings showed reduced expression levels of D1 and D2 in the striatum in OEA-treated mice (OEA-C, OEA-EXT and OEA-REINST) compared to the CTRL group. Similarly, examination of hippocampal gene expression revealed that OEA induced a decrease in D1 receptor in OEA-treated mice. These results are consistent with the reported ability of OEA to restore dopaminergic transmission in the striatum. For instance, Tellez et al.,  proved that OEA infusion restored the dopaminergic response to fat in mice fed chronically with a high-fat diet. This body of research argues for a role of OEA in regulating basal dopaminergic transmission in the striatum of mice.
Functional studies have demonstrated that TRPV1 activation increases dopaminergic neurotransmission in a variety of brain areas, including the striatum . A recent report has found that administration of a TRPV1 antagonist blocked cocaine CPP reinstatement and decreased D1-like receptor in the NAc, whilst an agonist potentiated cocaine-primed reinstatement . Although the molecular mechanisms have not been identified yet, our results suggest that OEA interacts with dopaminergic signaling in key brain regions for reward processing. Correlation analyses further confirms the important role of D1 receptor in reinstatement of the cocaine place preference as higher hippocampal DrD1 gene expression positively correlated with higher drug-induced reinstatement scores.
We also observed reduced expression of the CNR1 receptor in OEA-treated mice compared with the CTRL group. The major receptors responsible for cannabinoid-mediated effects are CB1 and CB2. A large body of research confirms the involvement of endocannabinoid lipids in the modulation of dopaminergic transmission and cocaine-induced reinstatement. CB1 receptors are present in high density in the striatum [52, 53]. It has been observed that the cannabinoid system modulates dopaminergic signaling mainly by acting on the TRPV1 receptor [54, 55]. As a non-cannabinoid NAEs, OEA does not directly bind to CB1 or CB2 but can potentiate the effects of other lipid messengers such as anandamide (“entourage effect”) . The reduction in gene expression of CNR1 observed in our study suggests a pharmacological effect of OEA on cocaine-priming. We hypothesize that OEA treatment alters the activity of CB1 receptors and ultimately reduces dopaminergic signaling in response to a single priming dose of cocaine. The correlation analyses also support this hypothesis. Results show a tendency towards a positive correlation between CNR1 gene expression and drug-induced reinstatement scores so that lower CNR1 gene expression in the hippocampus was correlated with a lower reinstatement preference. Of note, we did not observe any changes in the µ opioid receptor gene expression. To our knowledge, there are no reports of an OEA effect on the opioid system.
Our present understanding of OEA bioactivity includes binding to PPARα receptor and TRPV1. It is possible that OEA attenuates drug-induced reinstatement through D1 and D2 receptor activity in the striatum and hippocampus since there is a high density of PPARα receptors in these brain regions . It is important to remark that dopaminergic receptors are constantly adapting to the changing extracellular dopamine concentrations and thus, changes in receptor mRNA expression reflect their specific activity at the time of tissue collection for analysis. In addition, it is important to consider that mRNA expression does not necessarily correlate with the activity, affinity or sensitivity of the different receptors. Considering these shortcomings, further research should explore the specific pathways where OEA acts to counteract drug-induced dopamine plastic changes contributing to a greater risk of reinstatement.
In conclusion, our findings further support the previous pharmacological evidence of a modulatory effect of OEA on reward behavior. The present study shows that different OEA treatments prevent cocaine reinstatement mainly by modulating overall dopaminergic signaling in limbic areas including the striatum and hippocampus. Although the neuronal mechanisms have not been clearly defined, our results offer strong evidence of an attenuating effect of OEA on cocaine reinstatement.
Availability of data and materials
The data are available for any scientific use from the corresponding author on reasonable request.
National Institute on Drug Abuse (NIDA), National Institute on Drug Abuse (NIDA). (2021). Overdose death rates. https://www.drugabuse.gov/drug-topics/trends-statistics/overdose-death-rates. Accessed from 15 Mar 2021.
Brandt L, Chao T, Comer SD, Levin FR. Pharmacotherapeutic strategies for treating cocaine use disorder—what do we have to offer? Addiction. 2021;116(4):694–710. https://doi.org/10.1111/add.15242.
Nordfjærn T. Relapse patterns among patients with substance use disorders. J Subst Use. 2011;16(4):313–29. https://doi.org/10.3109/14659890903580482.
Shalev U. Neurobiology of Relapse to Heroin and Cocaine seeking: a review. Pharmacol Rev. 2002;54(1):1–42. https://doi.org/10.1124/pr.54.1.1.
Aguilar MA, Rodríguez-Arias M, Miñarro J. Neurobiological mechanisms of the reinstatement of drug-conditioned place preference. Brain Res Rev. 2009;59(2):253–77. https://doi.org/10.1016/j.brainresrev.2008.08.002.
Farrell MR, Schoch H, Mahler SV. Modeling cocaine relapse in rodents: behavioral considerations and circuit mechanisms. Prog Neuropsychopharmacol Biol Psychiatry. 2018;87:33–47. https://doi.org/10.1016/j.pnpbp.2018.01.002.
Di Chiara G. A motivational learning hypothesis of the role of mesolimbic dopamine in compulsive drug use. J Psychopharmacol. 1998;12(1):54–67. https://doi.org/10.1177/026988119801200108.
Wolf ME. Synaptic mechanisms underlying persistent cocaine craving. Nat Rev Neurosci. 2016;17(6):351–65. https://doi.org/10.1038/nrn.2016.39.
Shaham Y, Shalev U, Lu L, de Wit H, Stewart J. The reinstatement model of drug relapse: history, methodology and major findings. Psychopharmacology. 2003;168(1–2):3–20. https://doi.org/10.1007/s00213-002-1224-x.
Covey DP, Mateo Y, Sulzer D, Cheer JF, Lovinger DM. Endocannabinoid modulation of dopamine neurotransmission. Neuropharmacology. 2017;124:52–61. https://doi.org/10.1016/j.neuropharm.2017.04.033.
Lupica CR, Riegel AC. Endocannabinoid release from midbrain dopamine neurons: a potential substrate for cannabinoid receptor antagonist treatment of addiction. Neuropharmacology. 2005;48(8):1105–16. https://doi.org/10.1016/j.neuropharm.2005.03.016.
Maldonado C, Rodríguez-Arias M, Castillo A, Aguilar MA, Miñarro J. Gamma-hydroxybutyric acid affects the acquisition and reinstatement of cocaine-induced conditioned place preference in mice. Behav Pharmacol. 2006;17(2):119–31. https://doi.org/10.1097/01.fbp.0000190685.84984.ec.
Maldonado R, Valverde O, Berrendero F. Involvement of the endocannabinoid system in drug addiction. Trends Neurosci. 2006;29(4):225–32. https://doi.org/10.1016/j.tins.2006.01.008.
De Vries TJ, Shaham Y, Homberg JR, Crombag H, Schuurman K, Dieben J, Vanderschuren LJMJ, Schoffelmeer AN M. A cannabinoid mechanism in relapse to cocaine seeking. Nat Med. 2001;7(10):1151–4. https://doi.org/10.1038/nm1001-1151.
Luján M, Alegre-Zurano L, Martín-Sánchez A, Cantacorps L, Valverde O. CB1 receptor antagonist AM4113 reverts the effects of cannabidiol on cue and stress-induced reinstatement of cocaine-seeking behaviour in mice. Prog Neuropsychopharmacol Biol Psychiatry. 2022;113:110462. https://doi.org/10.1016/j.pnpbp.2021.110462.
Carey AN, Borozny K, Aldrich JV, McLaughlin JP. Reinstatement of cocaine place-conditioning prevented by the peptide kappa-opioid receptor antagonist arodyn. Eur J Pharmacol. 2007;569(1–2):84–9. https://doi.org/10.1016/j.ejphar.2007.05.007.
Redila VA, Chavkin C. Stress-induced reinstatement of cocaine seeking is mediated by the kappa opioid system. Psychopharmacology. 2008;200(1):59–70. https://doi.org/10.1007/s00213-008-1122-y.
Orio L, Alen F, Pavón FJ, Serrano A, García-Bueno B. Oleoylethanolamide, neuroinflammation, and alcohol abuse. Front Mol Neurosci. 2019;11:490. https://doi.org/10.3389/fnmol.2018.00490.
Sagheddu C, Torres LH, Marcourakis T, Pistis M. Endocannabinoid-like lipid neuromodulators in the regulation of dopamine signaling: relevance for drug addiction. Front Synaptic Neurosci. 2020;12:588660. https://doi.org/10.3389/fnsyn.2020.588660.
Bowen KJ, Kris-Etherton PM, Shearer GC, West SG, Reddivari L, Jones PJH. Oleic acid-derived oleoylethanolamide: a nutritional science perspective. Prog Lipid Res. 2017;67:1–15. https://doi.org/10.1016/j.plipres.2017.04.001.
Mennella I, Boudry G, Val-Laillet D. Ethanolamine produced from oleoylethanolamide degradation contributes to acetylcholine/dopamine balance modulating eating behavior. J Nutr. 2019;149(3):362–5. https://doi.org/10.1093/jn/nxy281.
Almási R, Szőke É, Bölcskei K, Varga A, Riedl Z, Sándor Z, Szolcsányi J, Pethő G. Actions of 3-methyl-N-oleoyldopamine, 4-methyl-N-oleoyldopamine and N-oleoylethanolamide on the rat TRPV1 receptor in vitro and in vivo. Life Sci. 2008;82(11–12):644–51. https://doi.org/10.1016/j.lfs.2007.12.022.
Wang X, Miyares RL, Ahern GP. Oleoylethanolamide excites vagal sensory neurones, induces visceral pain and reduces short-term food intake in mice via capsaicin receptor TRPV1: OEA activates vagal capsaicin receptors. J Physiol. 2005;564(2):541–7. https://doi.org/10.1113/jphysiol.2004.081844.
Fuchs RA, Evans KA, Ledford CC, Parker MP, Case JM, Mehta RH, See RE. The role of the dorsomedial prefrontal cortex, basolateral amygdala, and dorsal hippocampus in contextual reinstatement of cocaine seeking in rats. Neuropsychopharmacology. 2005;30(2):296–309. https://doi.org/10.1038/sj.npp.1300579.
Knackstedt LA, Trantham-Davidson HL, Schwendt M. The role of ventral and dorsal striatum mGluR5 in relapse to cocaine-seeking and extinction learning: MGluR5 and cocaine-seeking. Addict Biol. 2014;19(1):87–101. https://doi.org/10.1111/adb.12061.
McHugh MJ, Demers CH, Braud J, Briggs R, Adinoff B, Stein EA. Striatal-insula circuits in cocaine addiction: implications for impulsivity and relapse risk. Am J Drug Alcohol Abus. 2013;39(6):424–32. https://doi.org/10.3109/00952990.2013.847446.
Vorel SR, Liu X, Hayes RJ, Spector JA, Gardner EL. Relapse to cocaine-seeking after hippocampal theta burst stimulation. Science. 2001;292(5519):1175–8. https://doi.org/10.1126/science.1058043.
Jin P, Yu H-L, Tian-Lan, Zhang F, Quan Z-S. Antidepressant-like effects of oleoylethanolamide in a mouse model of chronic unpredictable mild stress. Pharmacol Biochem Behav. 2015;133:146–54. https://doi.org/10.1016/j.pbb.2015.04.001.
Lo Verme J, Fu J, Astarita G, La Rana G, Russo R, Calignano A, Piomelli D. The Nuclear receptor peroxisome proliferator-activated Receptor-α mediates the anti-inflammatory actions of Palmitoylethanolamide. Mol Pharmacol. 2005;67(1):15–9. https://doi.org/10.1124/mol.104.006353.
Thabuis C, Tissot-Favre D, Bezelgues J-B, Martin J-C, Cruz-Hernandez C, Dionisi F, Destaillats F. Biological Functions and Metabolism of Oleoylethanolamide. Lipids. 2008;43(10):887–94. https://doi.org/10.1007/s11745-008-3217-y.
Bilbao A, Blanco E, Luque-Rojas MJ, Suárez J, Palomino A, Vida M, Araos P, Bermúdez-Silva J, Fernández-Espejo E, Spanagel R, de Rodríguez F. Oleoylethanolamide dose-dependently attenuates cocaine-induced behaviours through a PPARα receptor-independent mechanism. Addict Biol. 2013;18(1):78–87. https://doi.org/10.1111/adb.12006.
González-Portilla M, Moya M, Montagud-Romero S, Rodríguez de Fonseca F, Orio L, Rodriguez-Arias M. Oleoylethanolamide attenuates the stress-induced conditioned rewarding properties of cocaine by modulating cerebellar TLR4 signaling pathway. Manuscript submitted for publication; 2022.
Bystrowska B, Frankowska M, Smaga I, Niedzielska-Andres E, Pomierny-Chamioło L, Filip M. Cocaine-Induced reinstatement of Cocaine seeking provokes changes in the endocannabinoid and N-Acylethanolamine levels in rat brain structures. Molecules. 2019;24(6):1125. https://doi.org/10.3390/molecules24061125.
Bystrowska B, Smaga I, Frankowska M, Filip M. Changes in endocannabinoid and N-acylethanolamine levels in rat brain structures following cocaine self-administration and extinction training. Prog Neuropsychopharmacol Biol Psychiatry. 2014;50:1–10. https://doi.org/10.1016/j.pnpbp.2013.12.002.
de Fonseca R, Navarro F, Gómez M, Escuredo R, Nava L, Fu F, Murillo-Rodríguez J, Giuffrida E, LoVerme A, Gaetani J, Kathuria S, Gall S, C., Piomelli D. An anorexic lipid mediator regulated by feeding. Nature. 2001;414(6860):209–12. https://doi.org/10.1038/35102582.
Antón M, Alén F, Gómez de Heras R, Serrano A, Pavón FJ, Leza JC, García-Bueno B, de Fonseca R, F., Orio L. Oleoylethanolamide prevents neuroimmune HMGB1/TLR4/NF-kB danger signaling in rat frontal cortex and depressive-like behavior induced by ethanol binge administration: OEA blocks ethanol TLR4 signaling. Addict Biol. 2017;22(3):724–41. https://doi.org/10.1111/adb.12365.
Plaza-Zabala A, Berrendero F, Suarez J, Bermudez-Silva FJ, Fernandez-Espejo E, Serrano A, Pavon F-J, Parsons LH, De Fonseca FR, Maldonado R, Robledo P. Effects of the endogenous PPAR-Î± agonist, oleoylethanolamide on MDMA-induced cognitive deficits in mice. Synapse. 2010;64(5):379–89. https://doi.org/10.1002/syn.20733.
Sayd A, Anton M, Alen F, Caso JR, Pavon J, Leza JC, de Fonseca R, Garcia-Bueno F, B., Orio L. Systemic administration of Oleoylethanolamide protects from Neuroinflammation and Anhedonia Induced by LPS in rats. Int J Neuropsychopharmacol. 2015;18(6):pyu111–1. https://doi.org/10.1093/ijnp/pyu111.
Zhou H, Yang W, Li Y, Ren T, Peng L, Guo H, Liu J, Zhou Y, Zhao Y, Yang L, Jin X. Oleoylethanolamide attenuates apoptosis by inhibiting the TLR4/NF-κB and ERK1/2 signaling pathways in mice with acute ischemic stroke. Naunyn-Schmiedeberg’s Archives of Pharmacology. 2017;390(1):77–84. https://doi.org/10.1007/s00210-016-1309-4.
Franklin KBJ, Paxinos G. The mouse brain in stereotaxic coordinates compact. Amsterdam Heidelberg: Elsevier Academic Press; 2008.
Daza-Losada M, Rodríguez-Arias M, Aguilar MA, Miñarro J. Acquisition and reinstatement of MDMA-induced conditioned place preference in mice pre-treated with MDMA or cocaine during adolescence. Addict Biol. 2009;14(4):447–56. https://doi.org/10.1111/j.1369-1600.2009.00173.x.
Mascia P, Pistis M, Justinova Z, Panlilio LV, Luchicchi A, Lecca S, Scherma M, Fratta W, Fadda P, Barnes C, Redhi GH, Yasar S, Le Foll B, Tanda G, Piomelli D, Goldberg SR. Blockade of nicotine reward and reinstatement by activation of alpha-type peroxisome proliferator-activated receptors. Biol Psychiatry. 2011;69(7):633–41. https://doi.org/10.1016/j.biopsych.2010.07.009.
Adamczyk P, McCreary AC, Przegalinski E, Mierzejewski P, Bienkowski P, Filip M. The effects of fatty acid amide hydrolase inhibitors on maintenance of cocaine and food self-administration and on reinstatement of cocaine-seeking and food-taking behavior in rats. Acta Physiol Pol. 2009;12(3):119.
Anderson SM, Schmidt HD, Pierce RC. Administration of the D2 dopamine receptor antagonist sulpiride into the shell, but not the core, of the nucleus accumbens attenuates cocaine priming-induced reinstatement of drug seeking. Neuropsychopharmacology. 2006;31(7):1452–61. https://doi.org/10.1038/sj.npp.1300922.
Alleweireldt AT, Weber SM, Kirschner KF, Bullock BL, Neisewander JL. Blockade or stimulation of D1 dopamine receptors attenuates cue reinstatement of extinguished cocaine-seeking behavior in rats. Psychopharmacology. 2002;159(3):284–93. https://doi.org/10.1007/s002130100904.
Hasbi A, Perreault ML, Shen MYF, Fan T, Nguyen T, Alijaniaram M, Banasikowski TJ, Grace AA, O’Dowd BF, Fletcher PJ, George SR. Activation of dopamine D1-D2 receptor complex attenuates Cocaine reward and reinstatement of Cocaine-Seeking through inhibition of DARPP-32, ERK, and ∆FosB. Front Pharmacol. 2018;8:924. https://doi.org/10.3389/fphar.2017.00924.
Milivojevič N, Krisch I, Sket D, Živin M. The dopamine D1 receptor agonist and D2 receptor antagonist LEK-8829 attenuates reinstatement of cocaine-seeking in rats. Naunyn-Schmiedeberg’s Archives of Pharmacology. 2004;369(6):576–82. https://doi.org/10.1007/s00210-004-0937-2.
Schmidt HD, Pierce RC. Cooperative activation of D1-like and D2-like dopamine receptors in the nucleus accumbens shell is required for the reinstatement of cocaine-seeking behavior in the rat. Neuroscience. 2006;142(2):451–61. https://doi.org/10.1016/j.neuroscience.2006.06.004.
Tellez LA, Medina S, Han W, Ferreira JG, Licona-Limón P, Ren X, Lam TT, Schwartz GJ, de Araujo IE. A gut lipid Messenger Links excess Dietary Fat to dopamine Deficiency. Science. 2013;341(6147):800–2. https://doi.org/10.1126/science.1239275.
Musella A, De Chiara V, Rossi S, Prosperetti C, Bernardi G, Maccarrone M, Centonze D. TRPV1 channels facilitate glutamate transmission in the striatum. Mol Cell Neurosci. 2009;40(1):89–97. https://doi.org/10.1016/j.mcn.2008.09.001.
You I-J, Hong S-I, Ma S-X, Nguyen T-L, Kwon S-H, Lee S-Y, Jang C-G. Transient receptor potential vanilloid 1 mediates cocaine reinstatement via the D1 dopamine receptor in the nucleus accumbens. J Psychopharmacol. 2019;33(12):1491–500. https://doi.org/10.1177/0269881119864943.
Kofalvi A. Involvement of cannabinoid receptors in the regulation of Neurotransmitter Release in the Rodent Striatum: a combined immunochemical and pharmacological analysis. J Neurosci. 2005;25(11):2874–84. https://doi.org/10.1523/JNEUROSCI.4232-04.2005.
Martín AB, Fernandez-Espejo E, Ferrer B, Gorriti MA, Bilbao A, Navarro M, de Fonseca R, F., Moratalla R. Expression and function of CB1 receptor in the rat striatum: localization and Effects on D1 and D2 dopamine receptor-mediated motor behaviors. Neuropsychopharmacology. 2008;33(7):1667–79. https://doi.org/10.1038/sj.npp.1301558.
García C, Palomo-Garo C, Gómez-Gálvez Y, Fernández-Ruiz J. Cannabinoid-dopamine interactions in the physiology and physiopathology of the basal ganglia: cannabinoid-dopamine interactions in basal ganglia. Br J Pharmacol. 2016;173(13):2069–79. https://doi.org/10.1111/bph.13215.
Melis M, Pillolla G, Luchicchi A, Muntoni AL, Yasar S, Goldberg SR, Pistis M. Endogenous fatty acid Ethanolamides suppress Nicotine-Induced activation of mesolimbic dopamine neurons through Nuclear receptors. J Neurosci. 2008;28(51):13985–94. https://doi.org/10.1523/JNEUROSCI.3221-08.2008.
Ho W-S, Barrett DA, Randall MD. Entourage’ effects of N -palmitoylethanolamide and N -oleoylethanolamide on vasorelaxation to anandamide occur through TRPV1 receptors: Effect of congeners on anandamide vasorelaxation. Br J Pharmacol. 2008;155(6):837–46. https://doi.org/10.1038/bjp.2008.324.
Galan-Rodriguez B, Suarez J, Gonzalez-Aparicio R, Bermudez-Silva FJ, Maldonado R, Robledo P, de Fonseca R, F., Fernandez-Espejo E. Oleoylethanolamide exerts partial and dose-dependent neuroprotection of substantia nigra dopamine neurons. Neuropharmacology. 2009;56(3):653–64. https://doi.org/10.1016/j.neuropharm.2008.11.006.
We wish to thank Guillem Chuliá for his English language editing.
This work was supported by the following Grants: PID-2020-112672RB-100 by MCIN/AEI/ https://doi.org/10.13039/501100011033 and ERDF A way of making Europe; Instituto de Salud Carlos III, Atención primaria, cronicidad y promoción de la salud, RED DE INVESTIGACIÓN EN ATENCIÓN PRIMARIA DE ADICCIONES (RIAPAd) RD21/0009/0005 and Unión Europea, ERDF A way of making Europe. Generalitat Valenciana, Conselleria de Educación, Dirección General de Universidades, Grupos de Investigación de excelencia PROMETEO (CIPROM/2021/080). MGP received the FPU Grant 18/06005.
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González-Portilla, M., Mellado, S., Montagud-Romero, S. et al. Oleoylethanolamide attenuates cocaine-primed reinstatement and alters dopaminergic gene expression in the striatum. Behav Brain Funct 19, 8 (2023). https://doi.org/10.1186/s12993-023-00210-1
- Gene expression