Nitric oxide increases interstitial excitatory amino acid release in the rat dorsomedial medulla oblongata.
In vivo microdialysis was employed to measure release of the neuroactive amino acids L-glutamate (Glu) and L-aspartate (Asp) in the dorsomedial medulla oblongata of the anaesthetised rat. Basal levels of endogenous extracellular Glu and Asp were increased over 5-fold and 3-fold, respectively, following perfusion with a depolarising stimulus of KCl. Intracerebral administration of the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP, 30 microM) caused a 5-fold increase in extracellular Asp and a 2-fold increase in extracellular Glu, which was blocked by Methylene blue. These data suggest that NO, acting through guanylate cyclase, can affect excitatory amino acid neurotransmission in the dorsomedial medulla oblongata.
Lawrence
A J
AJ
Department of Pharmacology, Monash University, Clayton, Australia.
Jarrott
B
B
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology; D001933:Brain Stem / Q000187:drug effects / Q000378:metabolism; D002531:Cerebellum / Q000187:drug effects / Q000378:metabolism; D003956:Dialysis; D005110:Extracellular Space / Q000187:drug effects / Q000378:metabolism; D005971:Glutamates / Q000494:pharmacology; D018698:Glutamic Acid; D007276:Injections, Intraventricular; D008297:Male; D008526:Medulla Oblongata / Q000187:drug effects / Q000378:metabolism*; D008751:Methylene Blue; D009569:Nitric Oxide / Q000494:pharmacology*; D010396:Penicillamine / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D011921:Rats, Inbred WKY; D026423:S-Nitroso-N-Acetylpenicillamine
D000596:Amino Acids; D005971:Glutamates; D001224:Aspartic Acid; D009569:Nitric Oxide; D018698:Glutamic Acid; D026423:S-Nitroso-N-Acetylpenicillamine; D010396:Penicillamine; D008751:Methylene Blue