Studies on the cause of changes of reactivity to hexobarbital in spontaneously hypertensive rats (SHR)

The hypnotic action of hexobarbital is weaker in spontaneously hypertensive rats (SHR) than in Wistar rats. The difference does not appear in young rats (up to the sixth week of life) and appears gradually concomitantly with maturation of animals. There was no correlation between the changes of reactivity to hexobarbital and development of hypertension. The rate of metabolism of hexobarbital was similar in SHR and Wistar rats. There is a close relationship between the changes in reactivity to hexobarbital and psychomotor activity: both are significantly higher in SHR than in Wistar rats. The results suggest that the main cause of a weaker action of hexobarbital in SHR is higher intensity of stimulatory processes in the central nervous system.