Presynaptic glutamate receptors modulate dopamine release from striatal synaptosomes.
The wide-ranging neuronal actions of glutamate are thought to be mediated by postsynaptic N-methyl-D-aspartate (NMDA) and non-NMDA receptors. The present report demonstrates the existence of presynaptic glutamate receptors in isolated striatal dopaminergic nerve terminals (synaptosomes). Activation of these receptors, by NMDA in the absence of Mg2+ and presence of glycine and by non-NMDA agonists in the presence of Mg2+, results in Ca(2+)-dependent release of dopamine from striatal synaptosomes. The release stimulated by NMDA is blocked by Mg2+ and by selective NMDA antagonists, whereas the release stimulated by selective non-NMDA agonists is blocked by a non-NMDA antagonist but not by Mg2+ or NMDA antagonists. Thus, these presynaptic glutamate receptors, localized on dopaminergic terminals in the striatum, appear to be pharmacologically similar to both the NMDA and the non-NMDA postsynaptic receptors. By modulating the release of dopamine, these presynaptic receptors may play an important role in transmitter interactions in the striatum.
Wang
J K
JK
Program in Neurosciences, Tufts University School of Medicine, Boston, Massachusetts 02111.
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D003342:Corpus Striatum / Q000648:ultrastructure*; D004298:Dopamine / Q000378:metabolism*; D005998:Glycine / Q000494:pharmacology; D008274:Magnesium / Q000494:pharmacology; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D013574:Synaptosomes / Q000378:metabolism* / Q000648:ultrastructure; D014316:Tritium
D017470:Receptors, Glutamate; D017981:Receptors, Neurotransmitter; D014316:Tritium; D008274:Magnesium; D002118:Calcium; D005998:Glycine; D004298:Dopamine