Uptake, release, and metabolism of D- and L-alpha-aminoadipate by rat cerebral cortex.
Accumulation of L-alpha-aminoadipate by rat cerebral cortical slices is a stereospecific and Na+-dependent process. The uptake of this compound is also temperature-dependent, with a Km of 1.6 X 10(-4)M for the high-affinity system. D-alpha-Aminoadipate has characteristics similar to those displayed by the L-isomer but to a lesser degree. L-Glutamate and L-aspartate inhibit the uptake of L-alpha-aminoadipate. D- and L-alpha-Aminoadipate are, respectively, weak uncompetitive and weak competitive inhibitors for the uptake of L-glutamate and L-aspartate. Both enantiomers inhibit GABA uptake but in quite different ways. The release of L-alpha-aminoadipate from the cerebral cortical slices is stimulated by a high concentration of K+ ions in the presence of Ca2+ in the perfusion buffer; the D-isomer displays this property to a lesser degree. The omission of Ca2+ markedly reduces the release of these two compounds. Less than 10% of the preloaded D- and L-alpha-aminoadipate are metabolized by the cerebral cortex during 40 min of superfusion. The possibility of L-alpha-aminoadipate as a neurotransmitter candidate is discussed.
D015074:2-Aminoadipic Acid / Q000378:metabolism*; D000600:Amino Acids, Dicarboxylic / Q000378:metabolism*; D000818:Animals; D001224:Aspartic Acid / Q000378:metabolism; D001921:Brain / Q000378:metabolism*; D002118:Calcium / Q000502:physiology; D004347:Drug Interactions; D005971:Glutamates / Q000378:metabolism; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D011188:Potassium / Q000502:physiology; D051381:Rats; D013237:Stereoisomerism; D005680:gamma-Aminobutyric Acid / Q000378:metabolism
D000600:Amino Acids, Dicarboxylic; D005971:Glutamates; D015074:2-Aminoadipic Acid; D001224:Aspartic Acid; D005680:gamma-Aminobutyric Acid; D011188:Potassium; D002118:Calcium