Nitric oxide regulates excitatory amino acid release in a biphasic manner in freely moving rats

Segieth, J., Getting, S.J., Biggs, C.S. and Whitton, P.S. (1995) Nitric oxide regulates excitatory amino acid release in a biphasic manner in freely moving rats. Neuroscience Letters, 200 (2). pp. 101-104. 10.1016/0304-3940(95)12088-L.

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DOI: 10.1016/0304-3940(95)12088-L

Abstract

The effect of altering hippocampal nitric oxide levels on basal and N-methyl-D-aspartate (NMDA) receptor-evoked release of glutamate and aspartate has been studied in freely moving rats. NMDA increased extracellular glutamate and aspartate in a concentration dependent manner. The nitric oxide synthase inhibitor L-nitro-arginine-methyl ester (L-NAME; 100 μM) increased basal glutamate and aspartate release, and also enhanced release of these amino acids evoked by NMDA (100μM) compared with the same concentration of NMDA infused alone. L-NAME at 200μM increased basal dialysate glutamate, but not aspartate; to a lesser extent than the 100μM concentration of the drug, and the NMDA-induced release of glutamate and aspartate was decreased. L-NAME at 1.0 mM did not significantly alter basal extracellular glutamate but significantly decreased dialysate aspartate, while abolishing the NMDA-evoked release of both amino acids. The actions of L-NAME were not mimicked by its much less active isomer D-nitro-arginine-methyl ester. The nitric oxide donor drag S-nitroso-N-penicillamine decreased dialysate glutamate and aspartate at a 500 μM concentration but increased the extracellular level of both amino acids when infused at 1.0 mM and 2.0 mM concentrations. These data suggest that nitric oxide may mediate both excitatory and inhibitory functions, according to the level of nitric oxide production in vivo.

Item Type:Article
Departments, units and centres:Department of Pharmacology > Department of Pharmacology
ID Code:3131
Journal or Publication Title:Neuroscience Letters
Deposited By:Library Staff
Deposited On:27 Apr 2012 17:53
Last Modified:27 Apr 2012 17:53

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