Auditory startle in normotensive and hypertensive rats

In the present experiment auditory startle was examined in male and female rats of the spontaneously hypertensive (SHR) and Wistar-Kyoto normotensive (WKY) strains and borderline hypertensive rats (BHR) derived from cross-breeding SHR females with WKY males. The magnitude of auditory startle declined over trials and was significantly higher in WKYs than in both SHRs and BHRs which did not differ from each other. These data add to an increasing body of literature concerning behavioral differences between hypertensive and normotensive rats and are discussed as they relate to the possible strain differences in either behavioral reactivity or tonic fear.