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

Segieth, Joanna and Getting, Stephen J. and Biggs, Christopher S. and Whitton, Peter S. (1995) Nitric oxide regulates excitatory amino acid release in a biphasic manner in freely moving rats. Neuroscience Letters, 200 (2). pp. 101-104. ISSN 0304-3940

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Official URL: http://dx.doi.org/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 ?M) increased basal glutamate and aspartate release, and also enhanced release of these amino acids evoked by NMDA (100 ?M) compared with the same concentration of NMDA infused alone. l-NAME at 200 ?M increased basal dialysate glutamate, but not aspartate, to a lesser extent than the 100 ?M 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 drug S-nitroso-N-penicillamine decreased dialysate glutamate and aspartate at a 500 ?M 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
Subjects: University of Westminster > Science and Technology > Life Sciences, School of (No longer in use)
Depositing User: Rachel Wheelhouse
Date Deposited: 24 Jul 2012 10:15
Last Modified: 24 Jul 2012 10:15
URI: http://westminsterresearch.wmin.ac.uk/id/eprint/10906

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