Nitric oxide increases interstitial excitatory amino acid release in the rat dorsomedial medulla oblongata

Abstract

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 KCI. Intracerebral administration of the nitric oxide (NO) donor S-nitroso-N-acetylpenicillamine (SNAP, 30 μM) 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 ..