[Effect of microenvironment on the conformation of m-cholinoreceptors in brain synaptic membranes]

Sensitivity of m-cholinergic receptor of synaptic membranes to SH-reagents (PChMB and NEM) was compared before and after its solubilization with detergents. PChMB blocked specific binding of m-antagonist QNB to both forms of the receptor in equal extent, while NEM was effective only after solubilization. After the membranes modification with butanol or arachidonic acid the membrane-bound receptor became sensitive to NEM. The solubilized receptor lost its ability to allosteric inhibition by acid. It is suggested that the receptor conformation is under the control of the membrane microenvironment.