Novel neural modulators.
The discovery that nitric oxide (NO) is produced by neurons and regulates synaptic activity has challenged the definition of a neurotransmitter. NO is not stored in synaptic vesicles and does not act at conventional receptors on the surface of adjacent neurons. The toxic gases carbon monoxide (CO) and hydrogen sulfide (H2S) are also produced by neurons and modulate synaptic activity. D-serine synthesis and release by astrocytes as an endogenous ligand for the "glycine" site of N-methyl D-aspartate (NMDA) receptors defy the concept that a neurotransmitter must be synthesized by neurons. We review the properties of these "atypical" neural modulators.
Boehning
Darren
D
Department of Neuroscience, Johns Hopkins University School of Medicine, 725 N. Wolfe Street, Baltimore, Maryland 21205, USA. dboehnin@jhmi.edu
Snyder
Solomon H
SH
D000596:Amino Acids / Q000378:metabolism*; D000818:Animals; D002248:Carbon Monoxide / Q000378:metabolism*; D006162:Guanylate Cyclase; D006801:Humans; D006862:Hydrogen Sulfide / Q000378:metabolism; D009130:Muscle, Smooth / Q000502:physiology; D009474:Neurons / Q000378:metabolism*; D018377:Neurotransmitter Agents / Q000145:classification / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism*; D018160:Receptors, Cytoplasmic and Nuclear / Q000378:metabolism; D000071756:Soluble Guanylyl Cyclase; D013569:Synapses / Q000378:metabolism*; D009435:Synaptic Transmission
D000596:Amino Acids; D018377:Neurotransmitter Agents; D018160:Receptors, Cytoplasmic and Nuclear; D009569:Nitric Oxide; D002248:Carbon Monoxide; D006162:Guanylate Cyclase; D000071756:Soluble Guanylyl Cyclase; D006862:Hydrogen Sulfide