NMDA, kainate, and AMPA depolarize nondopamine neurons in the rat ventral tegmentum.
The possible existence of N-methyl-D-aspartate (NMDA) and non-NMDA receptors on electrophysiologically identified nondopamine neurones in the ventral tegmental area (VTA) was tested in rat midbrain slice preparations. NMDA, kainate (KA), and AMPA (alpha-amino-3-hydroxy-5-methyl-4-isoxazole propionic acid) depolarized the membrane potential of nondopamine neurons in a dose-dependent manner. The NMDA effect was blocked by the selective NMDA receptor antagonist, CGS 19755 (cis-4-phosphonomethyl-2-piperidine carboxylate), but not by the non-NMDA receptor antagonist, NBQX [2,3-dihydroxy-6-nitro-7-sulfamoyl-benzo(F)quinoxaline]. In contrast, the effects of KA and AMPA were antagonized by NBQX, but not by CGS 19755. The rank order potency of the three agonists was AMPA > KA > NMDA, with thresholds of 0.1, 0.3, and 3 microM, respectively. These results provide clear electrophysiological evidence that nondopamine neurons in the ventral tegmental area possess both NMDA and non-NMDA receptors.
Wang
T
T
Department of Pharmacology, University of Arizona, College of Medicine, Tucson 85724.
French
E D
ED
D000818:Animals; D004594:Electrophysiology; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000494:pharmacology*; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology*; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D051381:Rats; D017207:Rats, Sprague-Dawley; D013681:Tegmentum Mesencephali / Q000166:cytology / Q000502:physiology*; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology*
D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D007608:Kainic Acid