The use of auto-anti-idiotypes for the visualization of acetylcholine receptors in an invertebrate skeletal muscle.

Polyclonal auto-anti-idiotypic antibodies (AAIs), detected in antisera of rabbits immunized with acetylcholine conjugate, have already been characterized. In this paper, we report on a cytochemical application of these AAIs on skeletal muscle motor endplates of an invertebrate. We have shown that there is a non-uniformly distributed reaction in the synaptic cleft. The deposits seem to be associated with the muscular plasma membrane. The specificity of the cytochemical method is discussed. On this kind of muscle, the AAIs are able to detect, at the ultrastructural level, acetylcholine binding sites which most likely are acetylcholine receptors.