Inhibition by the serotonin1A agonist, 8-hydroxy-2- (di-n-propylamino)tetralin, of antidromically identified paraventricular nucleus neurons in the rat.
Experiments were performed using urethane-anesthetized rats to delineate the role of serotonin (5-hydroxytryptamine, 5-HT) receptors of the 5-HT1A subtype in the neural regulation of hypothalamo-pituitary-adrenocortical (HPA) secretion. The activity of single paraventricular nucleus (PVN) neurons antidromically identified as projecting to the median eminence was recorded following injection of the 5-HT1A agonist, 8-hydroxy-2-(di-n-propylamino)tetralin (8-OH-DPAT). Intraperitoneal administration of increasing doses of 8-OH-DPAT caused dose-dependent decreases in the spontaneous activity of all neurons tested. The data yielded an ED50 value of 0.19 mumol/kg for this effect. The decreases in PVN neuronal activity were accompanied by sustained decreases in mean arterial blood pressure, with an ED50 of 0.18 mumol/kg. These results provide evidence for an inhibitory role of 5-HT1A receptors in the regulation of PVN neuronal activity and support the suggestion that 5-HT may inhibit HPA secretory activity.
Saphier
D
D
Department of Pharmacology, Louisiana State University Medical Center, Shreveport 71130-3932.
Zhang
K
K
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000008:administration & dosage / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D003346:Corticotropin-Releasing Hormone / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D004594:Electrophysiology; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000378:metabolism; D007274:Injections, Intraperitoneal; D007478:Iontophoresis; D008297:Male; D008473:Median Eminence / Q000187:drug effects / Q000502:physiology; D008839:Microelectrodes; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D010286:Paraventricular Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010913:Pituitary-Adrenal System / Q000187:drug effects / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D011985:Receptors, Serotonin / Q000187:drug effects / Q000502:physiology; D017366:Serotonin Receptor Agonists / Q000494:pharmacology*
D011985:Receptors, Serotonin; D017366:Serotonin Receptor Agonists; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin; D003346:Corticotropin-Releasing Hormone