Effect of soman on N-methyl-D-aspartate-stimulated [3H]norepinephrine release from rat cortical slices.

Effects of soman on N-methyl-D-aspartate (NMDA) evoked [3H]norepinephrine (NE) release were examined in rat brain cortical slices. NMDA increased [3H]NE release in a concentration-dependent manner. Soman could inhibit the increase evoked by NMDA, but carbachol, an agonist of cholinergic receptor, could potentiate the increase evoked by NMDA. Atropine (a selective muscarinic antagonist) attenuated the release of [3H]NE induced by NMDA in the presence of carbachol or acetylcholine (ACh), but had no effect on the release of [3H]NE induced by NMDA alone. Both d-tubocurarine (an antagonist of nicotinic receptor) and atropine had no effect on the release of [3H]NE induced by NMDA in the presence of soman. These results suggested that soman has a direct action at non-cholinergic sites, probably at NMDA receptors.