The Basolateral Amygdala in Mechanisms of Stress Resistance in Rats: The Role of Oligopeptides

Resumo

In order to study the role of the lateral amygdala in the peptidergic mechanisms of stress resistance in rats, we measured the levels of beta-endorphin and substance P in the blood and hypothalamus of stress-resistant and stress-responding rats during emotional stress under conditions of a functional blockade of the basolateral amygdala by anodic polarization. Emotional stress was created by immobilization of rats within narrow chambers, with additional aperiodic electrocutaneous stimulation. It was found that lateral areas of the amygdala play an important role in the maintenance of stress-resistance mechanisms in rats. Their bilateral blockade decreased the resistance to stress. As well, in our experiment we found reciprocal relationships between blood plasma and hypothalamic levels of peptides (substance P and beta-endorphin) both in stress-resistant and stress-responding rats. Thus, peptidergic mechanisms of stress resistance are associated with functioning of the amygdala.