Role of medial forebrain bundle catecholaminergic fibers in the modulation of glucocorticoid negative feedback effects.
The possible role of medial forebrain bundle (MFB) catecholaminergic fibers in the previously observed MFB-mediated modulation of hypothalamic sensitivity to glucocorticoid negative feedback effects has been investigated. MFB catecholaminergic fibers were destroyed by bilateral MFB injections of 6-hydroxydopamine (6-OHDA) to adult male rats. The inhibitory effect of dexamethasone (10 micrograms, i.p., 4 h) upon the adrenocortical secretory response to ether stress, as estimated by serum corticosterone levels, was enhanced in the 6-OHDA-treated animals, as compared to vehicle-injected controls. This study suggests that MFB noradrenergic neurons are at least partially responsible for the MFB-mediated modulation of hypothalamic sensitivity to glucocorticoid hormones.
D000818:Animals; D002395:Catecholamines / Q000502:physiology*; D002799:Cholinergic Fibers / Q000502:physiology*; D003345:Corticosterone / Q000097:blood*; D003907:Dexamethasone / Q000494:pharmacology; D005246:Feedback; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007033:Hypothalamus, Middle / Q000502:physiology; D008297:Male; D008474:Medial Forebrain Bundle / Q000502:physiology*; D009115:Muridae; D009434:Neural Pathways / Q000502:physiology*; D010913:Pituitary-Adrenal System / Q000502:physiology*; D013312:Stress, Physiological / Q000097:blood; D009435:Synaptic Transmission / Q000187:drug effects
D002395:Catecholamines; D003907:Dexamethasone; D003345:Corticosterone