The effect of chronic conflict on the blood pressure of rats with a genetic susceptibility to experimental hypertension.

Rats with a genetic susceptibility to experimental hypertension were exposed daily for 13 weeks to a conflict situation that resulted in food deprivation and the application of electric shock. Other subjects were either food deprived, shocked, both food deprived and shocked but without conflict, or not experimentally manipulated (control). Despite weekly fluctuations, a pattern emerged wherein subjects exposed to conflict usually exhibited the highest systolic blood pressures followed in order by subjects exposed to food deprivation and shock without conflict, rats food deprived, rats exposed to shock, and control subjects. Following this 13 week period, some of the rats in each group were allowed a 13 week stress-free-recovery period while the rest of the subjects were treated as before. During the recovery period most subjects' blood pressure returned to control levels. However, there was some indication in a few rats that elevations could persist for extended periods after the aversive treatment had been terminated. There is probably a genetic component involved in the reaction to stress that promotes the development of hypertension, just as there is to other hypertensinogenic stimuli.