An NMDA receptor on isolated secretory nerve endings.
While the presence of post-synaptic NMDA receptors in the CNS is well-established, the present study addressed the question of whether NMDA receptors may also be present on secretory nerve endings. Using microspectrofluorometry of fura-2 loaded isolated neurohypophysial nerve endings of the rat, we found that both glutamate (EC50 = 50 microM) and NMDA (EC50 = 30 microM) induced a rapid rise in (Ca2+]i. These responses were glycine-dependent and abolished by 1 mM Mg2+, 1 microM dizocilpine, and removal of extracellular Ca2+. Responses were not significantly affected by treatment with Ca2+ channel blockers or 10 microM CNQX.
Giovannucci
D R
DR
Department of Physiology, University of Michigan Medical School, Ann Arber 48109, USA.
Stuenkel
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EL
D000818:Animals; D002118:Calcium / Q000378:metabolism; D016291:Dizocilpine Maleate / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000494:pharmacology; D008297:Male; D016202:N-Methylaspartate / Q000494:pharmacology*; D009411:Nerve Endings / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism* / Q000502:physiology*
D016194:Receptors, N-Methyl-D-Aspartate; D018698:Glutamic Acid; D016202:N-Methylaspartate; D016291:Dizocilpine Maleate; D002118:Calcium