Acute and conditioned blood pressure changes in relation to social and psychosocial stimuli in rats.

The naturally occurring tendency to compete with other rats for territorial space has been used to study individual behavior characteristics and blood pressure reactivity to social stimuli in adult male TMD-S3 rats. The competitive characteristics of the individual rats are consistent in two different social situations (victory and defeat). Blood pressure responses during the victory of home territory rats over intruders was more pronounced in the more competitive animals. In addition to defeat by a trained fighter rat, the experimentals were also psychosocially stimulated by the fighter while it was confined in a small wire mesh cage. The blood pressure response to this event was enhanced by the prior defeat of the test animal by the one now confined to the small cage. This response was more pronounced in competitive rats. This approach has potential as an animal model of etiological processes in socially induced hypertension.