Distribution of acetylcholine receptors in the central nervous system of adult locusts.

A polyclonal antibody raised against nicotinic acetylcholine receptor protein from purified locust neuronal membrane was used to analyse the distribution of antigenic sites within the central nervous system of adult Schistocerca gregaria. Light microscopic examination showed that all principal neuropiles in the thoracic ganglia label with the antibody but that the major tracts and commissures do not. Analysis of this pattern of staining in the electron microscope reveals that the receptor is present on specific synaptic and extrajunctional neuronal membranes in the neuropile. Antigenic sites are also evident on the plasma membranes and within the cytoplasm adjacent to Golgi complexes of some neuronal somata, suggesting that these neurones synthesise nicotinic acetylcholine receptors. In addition to neuronal labelling, there is evidence that the receptor is also present on the membranes of three types of glial cells. The implications of this pattern of receptor distribution are discussed.