<正> Autoradiography of nicotinic acetytcholine receptors（N-ACHR）with the application ofhistochemical staining location of cholinesterase was used to observe the effect of soman onjunctional and extrajunctional N-AChR.Testing with the diaphragms and extensor digitorum longusmuscles of mice and rats

we found that soman mainly increased the number of extrajunctionalN-AChR.It did not alter the number of junctional N-AChR significantly

nor did it have any pro-nouneed effects on the gtycoprotein property and isoelectfic point（pI）of junctional andextrajunctional N-AChR.The change of extrajunctional N-AChR number caused by somanis similar to the phenomenon of increased extrajunctional N-AChR number and sensitivity resultingfrom denervation

but the mechanism of action is different from the latter.The increase ofN-AChR number is one of the important characteristics of soman poisoning which make it differ-ent from other nerve agents.To maintain the metabofic balance of N-AChR may be an importantnew approach to the treatment of soman poisoning.