This Article Full Text Full Text (PDF) All Versions of this Article: 145/8/3603    most recent Author Manuscript (PDF) Purchase Article View Shopping Cart Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Request Copyright Permission Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Shirakawa, T. Articles by Oguchi, H. Search for Related Content PubMed PubMed Citation Articles by Shirakawa, T. Articles by Oguchi, H.

Immobilization Induces Acute Nitric Oxide Production in the Rat Hypothalamus: A Role of Ionotropic Glutamate Receptors in the Paraventricular Nucleus

Center for Advanced Oral Medicine (T.S.), Hokkaido University Hospital, Sapporo 060-8586, Japan; and Departments of Oral Functional Science (M.M., T.K., W.N., S.O., T.H., H.O.) and Oral Pathobiological Science (M.S.), Graduate School of Dental Medicine, Hokkaido University, Sapporo 060-8586, Japan

Address all correspondence and requests for reprints to: Tetsuo Shirakawa, Ph.D., Center for Advanced Oral Medicine, Hokkaido University Hospital, N13W6 Kita-ku, Sapporo, 060-8586, Japan. E-mail: tshira{at}den.hokudai.ac.jp.

Abstract

Production of nitric oxide (NO) in the hypothalamic paraventricular nucleus (PVN) was examined by microdialysis in rats subjected to immobilization (IMO) stress. A dialysis probe was implanted in the posterior magnocellular subdivision of the PVN and nitrite (NO₂^–), an oxidized product of NO, was measured continuously. NO₂^– concentration in dialysate was enhanced to 156% after 30 min of IMO compared with the NO₂^– level before IMO. Intraperitoneal administration of N^G-monomethyl-L-arginine (10 mg/kg), a NO synthase inhibitor, before IMO completely inhibited the increase of NO production that IMO was to induce. Depletion of catecholamines innervating the PVN by an injection of 6-hydroxydopamine into the lateral ventricle before the microdialysis had no suppressive effect on the increase of NO production by IMO. In contrast, NO₂^– levels in the PVN were lowered by continuous perfusion of the solution containing the ionotropic glutamate receptor antagonists 2-amino-5-phosphonovaleric acid (500 µM) and 6-cyano-7-nitroquinoxaline-2, 3 dione (50 µM) through the dialysis probe, and the IMO-induced increase of NO production was attenuated by the treatment. These results suggest that catecholaminergic drive to the hypothalamus is not necessary for the IMO-induced increase of NO production and that ionotropic glutamate receptors play a role in the basal and IMO-induced NO production.

This article has been cited by other articles:

				S. Gingerich and T. L. Krukoff Estrogen in the Paraventricular Nucleus Attenuates L-Glutamate-Induced Increases in Mean Arterial Pressure Through Estrogen Receptor {beta} and NO Hypertension, December 1, 2006; 48(6): 1130 - 1136. [Abstract] [Full Text] [PDF]