Excitatory action of a plant extract, stizolobic acid, in the isolated spinal cord of the rat.
Actions of stizolobic acid, stizolobinic acid and their derivatives were examined on the isolated spinal cord of the newborn rat. The responses were recorded from the ventral root. Stizolobic acid and its bromo-derivatives caused a depolarizing response in a dose-dependent manner. Stizolobinic acid was considerably less potent than stizolobic acid. Depolarizing responses to stizolobic acid and its bromo-derivatives were not affected by the existence of Mg2+ and specific N-methyl-D-aspartate (NMDA) antagonists. Kynurenate depressed responses to stizolobic acid. These results suggest that stizolobic acid is a new excitatory amino acid in the mammalian central neurons which binds preferably to other receptors than the NMDA-type receptor.
Ishida
M
M
Tokyo Metropolitan Institute of Medical Science, Japan.
Shinozaki
H
H
D000200:Action Potentials / Q000187:drug effects; D000596:Amino Acids / Q000494:pharmacology; D000600:Amino Acids, Dicarboxylic / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D066298:In Vitro Techniques; D010936:Plant Extracts / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains; D013116:Spinal Cord / Q000187:drug effects / Q000502:physiology*
D000596:Amino Acids; D000600:Amino Acids, Dicarboxylic; D010936:Plant Extracts; C013261:stizolobic acid