Specific polyclonal antibodies against M1 and M2 subtypes of cholinergic receptors were prepared in this laboratory.The M-cholinoceptor molecules in brain homogenate were solubilized with 1% digitonin and labelled with 3H-QNB prior to immumuprecipitation. One of the specific antibodies was then added to form antigen-antibody complex with the respective subtype and the complex was precipitated by the aid of a second antibody. Thus the receptor-ligand binding parameters of a single subtype were obtained from the radioactivities of the precipitates.Typical single- site saturation curves were obtained for both M1 and M2 subtypes.No influence of the antibodies on receptor-ligand binding was detected.Results of studies on the solubilization of menbrane receptors

the time course of antibody-antigen reaction

the optimal dilution factor and the reaction temperature are also presented in the paper.