Two-way shuttle box and lever-press avoidance in the spontaneously hypertensive and normotensive rat

These experiments characterized behaviorally two strains of rat that have been selectively bred for blood pressure differences. Avoidance performances of the spontaneously hypertensive rat (SHR) and normotensive rat (WKYN) were examined under two conditions: a discrete-trial two-way shuttle box avoidance procedure and a discrete-trial lever-press avoidance procedure. The WKYN strain reached a higher level of acquisition in the two-way shuttle box task than the SHR strain, but this difference was confounded by an initial difference in pretest avoidance rate. In contrast, the SHR strain was superior in the lever-press avoidance procedure under all conditions employed. These data are interpreted as being consistent with a hypothesis offered by Satinder that strains selectively bred for some behavioral feature may also differ in central arousal which will interact with task difficulty to determine performance differences. The data clearly indicate that the selective breeding for high and low blood pressure has simultaneously influenced the behavioral properties of these two strains.