Reverse microdialysis of ionotropic glutamate receptor agonists in the rat globus pallidus increased extracellular dopamine.
The globus pallidus (GP) receives a prominent dopamine (DA) input by collaterals from the nigrostriatal pathway. However, the neurochemical regulation of extracellular DA in the GP is unknown at present. In the present study we investigated whether activation of ionotropic glutamate receptors by reverse microdialysis of NMDA and AMPA elicits changes in extracellular DA in the GP. Results show that reverse microdialysis of 70 microM AMPA and of 1 mM NMDA produced a significant and reversible increase of dialysate DA levels to about 130% and 160%, respectively. These data provide evidence that ionotropic glutamate receptors in the GP exert excitatory actions on DA release which might be brought about by actions on presynaptic ionotropic glutamate receptors in the GP or involve stimulation of midbrain DA neurons through trans-synaptic pathways.
Abteilung Tierphysiologie, Biologisches Institut, Universität Stuttgart, Pfaffenwaldring 57, D-70550 Stuttgart, Germany.
Holger
H
Fuchs
Wolfgang
W
Hauber
D000818:Animals; D004298:Dopamine / Q000378:metabolism*; D018690:Excitatory Amino Acid Agonists; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005917:Globus Pallidus / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D017551:Microdialysis / Q000379:methods*; D016202:N-Methylaspartate / Q000494:pharmacology*; D051381:Rats; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology*
D018690:Excitatory Amino Acid Agonists; D016202:N-Methylaspartate; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D004298:Dopamine