title: Release of neuroactive substances: homocysteic acid as an endogenous agonist of the NMDA receptor.
abstract: Sulfur containing amino acids such as homocysteic acid (HCA), cysteinsulfinic acid, homocysteinsulfinic acid are released by depolarization of slices from various rat brain regions in a Ca++-dependent manner. L-HCA excites caudate neurons through their N-methyl-D-aspartic acid (NMDA) receptor and potentiates their cortically evoked excitatory postsynaptic potentials. 35S-methionine can label the releasable pool of HCA, and thus appears as a precursor of HCA. Thus HCA is a transmitter candidate which acts predominantly on the NMDA receptor.
mesh_terms: D000818:Animals; D001224:Aspartic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D001921:Brain / Q000378:metabolism; D002851:Chromatography, High Pressure Liquid; D003545:Cysteine / Q000031:analogs & derivatives / Q000378:metabolism / Q000494:pharmacology; D006710:Homocysteine / Q000031:analogs & derivatives* / Q000378:metabolism / Q000494:pharmacology / Q000502:physiology; D016202:N-Methylaspartate; D018377:Neurotransmitter Agents / Q000378:metabolism*; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter / Q000502:physiology*; D014018:Tissue Distribution
chemical_list: D018377:Neurotransmitter Agents; D016194:Receptors, N-Methyl-D-Aspartate; D017981:Receptors, Neurotransmitter; D006710:Homocysteine; C007956:homocysteic acid; D001224:Aspartic Acid; C010982:homocysteinesulfinic acid; D016202:N-Methylaspartate; D003545:Cysteine; C013461:cysteine sulfinic acid