Influence of hypothalamically‐elicited emotional behaviours on the circulating plasma volume, plasma levels of catecholamines, ACTH and cortisol

Abstract

Influence of hypothalamically-induced emotional behaviours on the plasma volume, plasma levels of epinephrine (E), norepinephrine (NE), dopamine (DA), ACTH and cortisol were examined in cats. The emotional behaviours consisting of restlessness, threat and searching-biting (S-B) were elicited intermittently for 6 h by electrical stimulation of the anterior, ventromedial, and lateral hypothalamus, respectively in awake and free-moving conditions. The blood was sampled three times immediately before, 1 h after and 6 h after the start of stimulation. The E level increased in both restlessness and threat after 1 h, then the levels tended to decrease after 6 h, whereas the NE level increased in both restlessness and threat after 1 h and furthermore increased after 6 h. The plasma ACTH once increased after 1 h in all behaviours thereafter, the level tended to decrease after 6 h. The plasma cortisol level increased in both restlessness and threat behaviours both after 1 and 6 h. The plasma volume in S-B behaviour increased after 6 h, while in restlessness and threat behaviours it decreased markedly and tended to decrease more in threat than in restlessness after 1 h. These results indicate that the hypothalamically-induced threat and restlessness behaviours elicited marked activation of sympatho-adrenomedullary and pituitary adrenocortical systems and hemoconcentration, whereas the S-B behaviour hardly produced such stress responses.