Brudzynski_1984_Behav.Brain.Res_14_247

Unilateral injections of carbachol (CCh, 10 micrograms) into the anterior hypothalamic/preoptic area of cats caused an inhibition of locomotor activity measured in two different ways in 4-field and 100-field activity boxes. This inhibition was accompanied by crouched posture of the cat's body, general arousal with increased number of searching head movements, autonomic manifestations, and vocalization. Recordings of the growling component of vocalization, serving as a quantitative index of CCh-induced emotional-aversive response, showed that the period of maximal inhibition of locomotor activity coincided with the peak values of vocalization. We conclude that direct injections of CCh into the anterior hypothalamic/preoptic area in cats activate a central mechanism responsible for an inhibition of locomotor activity. This inhibition seems to be one of the natural components of defensive responses, further supporting the suggestion that the CCh-induced emotional-aversive response is equivalent to naturally occurring defensive behavior in cats.