title: alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionate receptors modulate dopamine release in rat hippocampus and striatum.
abstract: The effects of infusing the glutamate receptor agonist alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate (AMPA) on the release of dopamine (DA) has been studied in rat hippocampus and striatum in vivo. In hippocampus, AMPA (1-10 microM) produced a dose related increase in dialysate DA, but at 100 microM AMPA a sustained decrease in extracellular DA was observed. However, when samples were collected at 5-min intervals 100 microM AMPA infusion revealed a brief increase in hippocampal dialysate DA. Infusion of 100 microM AMPA and 500 microM diazoxide, which blocks AMPA receptor desensitization, led to a marked increase in extracellular DA, as did diazoxide alone, although to a lesser extent. The AMPA receptor antagonist 6-cyano-7-nitroquinoxaline-2,3,-dione (CNQX; 200 microM) reversed the effect of AMPA and/or diazoxide infusion on dialysate DA and when infused alone, CNQX also decreased hippocampal dialysate DA. AMPA (50-500 microM) increased striatal DA release. The effect of AMPA on extracellular DA was reversed by CNQX (200 microM). Diazoxide infusion caused a decrease in striatal DA release, and this was not affected by CNQX. These data suggest that hippocampal, but not striatal AMPA receptor desensitization may play a role in regulating DA release.
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000818:Animals; D003342:Corpus Striatum / Q000187:drug effects*; D003981:Diazoxide / Q000494:pharmacology; D004298:Dopamine / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D006624:Hippocampus / Q000187:drug effects*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D018091:Receptors, AMPA / Q000187:drug effects*; D013997:Time Factors; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology*
chemical_list: D018091:Receptors, AMPA; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D003981:Diazoxide; D004298:Dopamine