SHRs show increased locomotor and rearing activity. Naïve SHR and WIS rats were exposed to an activity/open field box and their spontaneous motor activity was recorded for 1 h. (A) Distance traveled (meters) as a function of time during the 60 min open field test. (B) Representative tracks of movement patterns of SHR and WIS rats during the initial 10 min of testing and at the 50-60 min time interval of testing. Distance traveled and rearing activity are shown in brown and blue colors, respectively. (C) Number of rears as a function of time during the 60 min open field test. All data (A and C) are represented as mean ± S.M.E. (N = 5 animals per group). *P < 0.05, **P < 0.001 when compared to WIS rats.