Modulation of the number of muscarinic receptors in mouse neuroblastoma cells by soman.

Long-term preincubation at 37 degrees of mouse neuroblastoma cells (clones NS-20 and N1E-115) with soman, a potent and irreversible cholinesterase inhibitor, resulted in a significant decrease in the number of [3H]N-methylscopolamine binding sites and in the inhibition of carbamylcholine-induced cyclic GMP formation. The disappearance of surface muscarinic receptors and the desensitization of the receptor-mediated response seem to occur via accumulation of acetylcholine in the culture medium. The significance of these findings is discussed.