Atypical neural messengers.
Notions of what constitutes a neurotransmitter have changed markedly with the advent in the past decade of synaptic molecules, which satisfy key neurotransmitter criteria but differ radically from classical transmitters. Thus, NO and carbon monoxide are neither stored in synaptic vesicles nor released by exocytosis. These gases do not act via traditional receptors on postsynaptic membranes. In addition, zinc, stored together with glutamate in synaptic vesicles, appears to act as an 'antagonist' co-transmitter at the NMDA receptor, and although localized exclusively to glia, D-serine fulfills most neurotransmitter criteria as an endogenous ligand for the 'glycine' site of NMDA receptors.
Barañano
D E
DE
Johns Hopkins University School of Medicine, Dept of Neuroscience, 725 N. Wolfe Street, Baltimore, MD 21205, USA.
Ferris
C D
CD
Snyder
S H
SH
D000818:Animals; D002248:Carbon Monoxide / Q000378:metabolism; D018698:Glutamic Acid / Q000378:metabolism; D006801:Humans; D009457:Neuroglia / Q000378:metabolism; D018377:Neurotransmitter Agents / Q000378:metabolism; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000378:metabolism; D052248:Nitric Oxide Synthase Type I; D016194:Receptors, N-Methyl-D-Aspartate / Q000378:metabolism; D015290:Second Messenger Systems / Q000502:physiology*; D012694:Serine / Q000378:metabolism; D013572:Synaptic Vesicles / Q000378:metabolism; D015032:Zinc / Q000378:metabolism
D018377:Neurotransmitter Agents; D016194:Receptors, N-Methyl-D-Aspartate; D009569:Nitric Oxide; D018698:Glutamic Acid; D012694:Serine; D002248:Carbon Monoxide; C496320:NOS1 protein, human; D019001:Nitric Oxide Synthase; D052248:Nitric Oxide Synthase Type I; D015032:Zinc