N‐methyl‐d‐Aspartic Acid Differentially Regulates Extracellular Dopamine, GABA, and Glutamate Levels in the Dorsolateral Neostriatum of the Halothane‐Anesthetized Rat: An In Vivo Microdialysis Study

Publisher Website
Google Scholar
Abstract
The effects of local perfusion with the glutamate receptor agonist NMDA and the noncompetitive NMDA receptor antagonist dizolcipine (MK-801) on extracellular dopamine (DA), GABA, and glutamate (Glu) levels in the dorsolateral striatum were monitored using in vivo microdialysis in the halothane-anesthetized rat. In addition, the sensitivity of both the basal and NMDA-induced increases in levels of these neurotransmitter substances to perfusion with tetrodotoxin (TTX; 10−5 M) and a low Ca2+ concentration (0.1 mM) was studied. The results show that the local perfusion (10 min) with both the 10−3 and 10−4 M dose of NMDA increased striatal DA and GABA outflow, whereas only the (10−3 M) dose of NMDA was associated with a small and delayed increase in extracellular Glu levels. The NMDA-induced effects were dose-dependently counteracted by simultaneous perfusion with MK-801 (10−6 and 10−5 M). Both the basal and NMDA (10−3 M)-induced increase in extracellular striatal DA content was reduced in the presence of TTX and a low Ca2+ concentration, whereas both basal and NMDA-stimulated GABA levels were unaffected by these treatments. Both the basal and NMDA-stimulated Glu levels were enhanced following TTX treatment, whereas perfusion with a low Ca2+ concentration reduced basal Glu levels and enhanced and prolonged the NMDA-induced stimulation. These data support the view that NMDA receptor stimulation plays a role in the regulation of extracellular DA, GABA, and Glu levels in the dorsolateral neostriatum and provide evidence for a differential effect of NMDA receptor stimulation on these three striatal neurotransmitter systems, possibly reflecting direct and indirect actions mediated via striatal NMDA receptors.

This publication has 50 references indexed in Scilit: