Cardiovascular and motor components of the defence reaction elicited in rats by electrical and chemical stimulation in amygdala.

In rats anesthetized with Saffan, electrical and chemical (D,L-homocysteic acid, DLH) stimulation in amygdala complex induced vasodilation in the hindlimb muscle, renal vasoconstriction and tachycardia. Chemical stimulation of cell bodies was effective only in the basolateral nucleus, while electrical stimulation produced the response from a larger area: central, basolateral and basomedial nuclei of amygdala. In non-anaesthetized rats, electrical stimulation in these nuclei elicited arching of the back, piloerection, sitting up and boxing with the forepaws or running, jumping or squealing. It is concluded that the area within the amygdala complex controlling the defence reaction is probably restricted to the basolateral nucleus, responses obtained from neighbouring nuclei might be due to activation of the afferent or efferent pathways leading to or from the basolateral nucleus.