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.
Cervetto
Chiara
C
Department of Experimental Medicine, Pharmacology and Toxicology Section, University of Genoa, Genoa, Italy.
Maura
Guido
G
Marcoli
Manuela
M
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