title: Endothelin-3 directly affects neurons in the anteroventral third ventricle region and supraoptic nucleus of the rat hypothalamus in vitro.
abstract: Extracellular recordings were made from anteroventral third ventricle (AV3V) and supraoptic nucleus (SON) neurons of rat hypothalamus in slice preparations. ET-3 was applied at concentrations of 10(-10) to 3 x 10(-7) M. Of 119 AV3V neurons tested, 21 (18%) were excited, 8 (6%) were slightly inhibited, and 90 (76%) were unaffected. The threshold concentration to evoke responses was approximately 10(-8) M. Excitatory responses of the AV3V neurons to ET-3 remained in a Ca(2+)-free medium. Of 120 SON neurons tested, 46 were phasic (putative vasopressin neuron) and 74 were nonphasic (putative oxytocin neuron). Of 46 phasic neurons tested, 26 (56.5%) were inhibited by ET-3, 20 (43.5%) were nonresponsive, and none was excited. Of 74 nonphasic neurons tested, 14 (19%) neurons were inhibited by ET-3, 60 (81%) were nonresponsive, and none was excited. These results suggest that ET-3 has dual effects on AV3V and SON neurons and the mechanisms of the responses may be different in the AV3V and SON neurons.
authors.affiliation: First Department of Physiology, School of Medicine, University of Occupational and Environmental Health, Kitakyushu, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Yamashita
authors.forename: S
authors.initials: S
authors.lastname: Yamamoto
authors.forename: K
authors.initials: K
authors.lastname: Inenaga
authors.forename: H
authors.initials: H
authors.lastname: Kannan
mesh_terms: D000818:Animals; D002552:Cerebral Ventricles / Q000187:drug effects*; D004594:Electrophysiology; D016232:Endothelins / Q000494:pharmacology*; D007031:Hypothalamus / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D011919:Rats, Inbred Strains; D013495:Supraoptic Nucleus / Q000187:drug effects*
chemical_list: D016232:Endothelins