Glutamate metabotropic receptor activation in neonatal rat cerebral cortex by sulphur-containing excitatory amino acids.
The sulphur-containing acidic amino acids (SAAs) display neuroexcitatory actions similar to those of L-glutamate and are widely regarded as bona fide transmitter candidates. In this study, L-cysteine sulphinic acid, L-cysteic acid, DL-homocysteic acid and L-homocysteine sulphinic acid were investigated for their ability to stimulate phosphatidylinositol hydrolysis in rat pup cerebrocortical slices and compared with L-glutamate and the selective agonist (1S,3R)-1-aminocyclopentane-1,3-dicarboxylic acid ((1S,3R)-ACPD). Each of the SAAs possessed agonist activity at metabotropic glutamate receptors (mGluRs) and, although they exhibited lower efficacy than L-glutamate, they were more potent (EC50s of 401-487 microM compared with 791 microM for L-glutamate). These data are consistent with the possibility that SAAs may have a physiological role as endogenous activators of metabotropic (and presumably ionotropic) excitatory amino acid receptors.
Department of Physiology and Pharmacology, University of Southampton, UK.
R H
RH
Porter
P J
PJ
Roberts
D000603:Amino Acids, Sulfur / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn / Q000378:metabolism*; D001711:Biotransformation / Q000187:drug effects; D002540:Cerebral Cortex / Q000187:drug effects / Q000378:metabolism*; D003515:Cycloleucine / Q000031:analogs & derivatives / Q000494:pharmacology; D066298:In Vitro Techniques; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D017470:Receptors, Glutamate / Q000187:drug effects / Q000378:metabolism*
D000603:Amino Acids, Sulfur; D019269:Phosphatidylinositol 4,5-Diphosphate; D010716:Phosphatidylinositols; D017470:Receptors, Glutamate; D003515:Cycloleucine; C036361:1-amino-1,3-dicarboxycyclopentane