Inhibition of presynaptic release-facilitatory kainate autoreceptors by extracellular cyclic GMP.
We found that both alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) and kainate autoreceptors were present on the glutamate-releasing terminals of cerebellar parallel/climbing fibers and that they functioned as facilitatory autoreceptors. Extracellular cGMP inhibited the neurotransmitter release evoked by presynaptic kainate receptor activation; the inhibitory effect of extracellular cGMP was selective for the kainate autoreceptor-mediated response and did not affect the AMPA autoreceptor-mediated response. Endogenously synthesized cGMP might be the physiological source for the extracellular cGMP modulating the response to kainate autoreceptor activation.
Department of Experimental Medicine, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy.
Chiara
C
Cervetto
Guido
G
Maura
Manuela
M
Marcoli
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D017660:Autoreceptors / Q000037:antagonists & inhibitors*; D002531:Cerebellum / Q000378:metabolism; D006152:Cyclic GMP / Q000378:metabolism / Q000502:physiology*; D004305:Dose-Response Relationship, Drug; D005110:Extracellular Space / Q000378:metabolism*; D018698:Glutamic Acid / Q000378:metabolism; D066298:In Vitro Techniques; D007608:Kainic Acid / Q000494:pharmacology; D008297:Male; D017729:Presynaptic Terminals / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D018091:Receptors, AMPA / Q000378:metabolism; D018092:Kainic Acid Receptors / Q000037:antagonists & inhibitors*; D013574:Synaptosomes / Q000378:metabolism
D001224:Aspartic Acid; D017660:Autoreceptors; D006152:Cyclic GMP; D018698:Glutamic Acid; D007608:Kainic Acid; D018091:Receptors, AMPA; D018092:Kainic Acid Receptors