Actions of N-methyl aspartate and its antagonist aminophosphonovalerate on the A5 catecholamine cell group in rat.

When N-methyl-D,L-aspartic acid was injected into the A5 catecholamine cell group of the rat, a dose-dependent decrease in blood pressure and heart rate was obtained. These cardiovascular changes were subsequently blocked by the (-) and (+) isomers of the aspartate receptor blocker 2-amino-5-phosphonovalerate (2-amino-5-phosphonopentanoic acid). The (-) isomer was 2-4 times more potent than the (+) form.