Neurotransmitter modulation of corticotropin releasing factor secretion into the hypophysial-portal circulation.
Secretion of corticotropin releasing factor (CRF) from the hypothalamic paraventricular nuclei into the hypophysial-portal circulation is modulated by a variety of neuronal afferents. Effects of intracerebroventricular acetylcholine (ACH), gamma-aminobutyric acid (GABA) and epinephrine (EPI) on immunoreactive (ir) CRF concentration in portal plasma were directly evaluated in urethanized male rats. ACH (0.1-10 nmole) administration was associated with a dose-dependent elevation of portal irCRF which was attenuated by pretreatment with either muscarinic or nicotinic receptor antagonists. GABA (0.1-10 nmole) also caused inhibition of irCRF concentration in the portal plasma which was prevented by bicuculline pretreatment. Finally, EPI (0.1-10 nmole) facilitated irCRF secretion via alpha 1- and beta-adrenergic mechanisms. These observations provide the first direct information on possible neurotransmitter actions on hypothalamic CRF secretion.
D000109:Acetylcholine / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001640:Bicuculline / Q000494:pharmacology; D002552:Cerebral Ventricles / Q000187:drug effects / Q000502:physiology*; D003346:Corticotropin-Releasing Hormone / Q000097:blood / Q000378:metabolism*; D004837:Epinephrine / Q000008:administration & dosage / Q000494:pharmacology*; D007030:Hypothalamo-Hypophyseal System / Q000098:blood supply*; D007276:Injections, Intraventricular; D008297:Male; D009474:Neurons / Q000502:physiology; D010286:Paraventricular Hypothalamic Nucleus / Q000187:drug effects / Q000378:metabolism*; D010393:Pempidine / Q000494:pharmacology; D011433:Propranolol / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D012601:Scopolamine / Q000494:pharmacology; D015016:Yohimbine / Q000494:pharmacology; D005680:gamma-Aminobutyric Acid / Q000008:administration & dosage / Q000494:pharmacology*
D015016:Yohimbine; D005680:gamma-Aminobutyric Acid; D003346:Corticotropin-Releasing Hormone; D011433:Propranolol; D012601:Scopolamine; D010393:Pempidine; D000109:Acetylcholine; D001640:Bicuculline; D004837:Epinephrine