Involvement of amygdalar alpha adrenoceptors in hypothalamo-pituitary-adrenocortical responses.
We have previously demonstrated that the facilitatory effect of the amygdala on the hypothalamo-pituitary-adrenocortical (HPA) axis responses to photic stimulation depends on the presence of norepinephrine (NE) in this region. In the present study we investigated the effect of alpha 1- and beta-adrenoceptor blockers, injected into the central amygdala nucleus, on the HPA responses. In intact freely moving rats, short photic stimulation caused depletion of CRH-41 from the median eminence, due to its release into the portal circulation and a rise in serum ACTH and corticosterone levels. This effect was markedly inhibited by injection of prazosin, an alpha 1-adrenoceptor blocker, but atenolol, a beta 1 blocker, had no effect. These data further indicate that amygdala NE plays a role in the activation of the HPA axis following neural stimuli and that this effect is mediated by alpha 1-adrenoceptors in the central amygdala.
Feldman
S
S
Department of Neurology, Hadassah University Hospital, Jerusalem, Israel.
Weidenfeld
J
J
D000302:Adrenal Cortex / Q000187:drug effects / Q000502:physiology*; D000316:Adrenergic alpha-Agonists / Q000494:pharmacology; D000317:Adrenergic alpha-Antagonists / Q000008:administration & dosage / Q000494:pharmacology; D000679:Amygdala / Q000187:drug effects / Q000502:physiology*; D000818:Animals; D001262:Atenolol / Q000008:administration & dosage / Q000494:pharmacology; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology*; D007150:Immunohistochemistry; D007267:Injections; D008297:Male; D009638:Norepinephrine / Q000494:pharmacology; D010775:Photic Stimulation; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000502:physiology*; D011224:Prazosin / Q000008:administration & dosage / Q000494:pharmacology; D051381:Rats; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*
D000316:Adrenergic alpha-Agonists; D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; D001262:Atenolol; D009638:Norepinephrine; D011224:Prazosin