Immunocytochemical evaluation of a cholinergic-specific ganglioside antigen (Chol-1) in the central nervous system of the rat.

Previous work from this laboratory has identified gangliosidic surface markers specific for cholinergic neurons. Antibodies to these markers, collectively designated Chol-1, induce complement-mediated lysis of the cholinergic subpopulation of synaptosomes and provide the basis for a new immunocytochemical method for staining cholinergic neurons in rat, guinea pig and human material. The specification and localization of immunocytochemical staining for Chol-1 was investigated in selected areas of the rat central nervous system. The antigen was typically expressed on all neurons previously identified as being cholinergic using monoclonal antibodies to choline acetyltransferase. At spinal levels Chol-1 was present on large and smaller cell bodies in the ventral horn motoneuron area. The preganglionic sympathetic neurons in the thoracic intermediolateral nucleus were also Chol-1-positive. Nerve terminal-like staining was observed in association with stained large Chol-1 positive and smaller unstained Chol-1 negative neurons, and in lamina I and III of the dorsal horn. In the mesencephalon, motoneurons of the oculomotor and trochlear nucleus, as well as neurons within the pedunculopontine tegmental nucleus and the red nucleus were Chol-1-positive. In addition visceromotoneurons of the Edinger-Westphal nucleus were stained with anti-Chol-1 antibodies. In the basal forebrain the antibodies gave a positive reaction on well known cholinergic neurons in the vertical and horizontal limbs of the diagonal bands of Broca and the medial forebrain bundle. In agreement with studies using antibodies to choline acetyltransferase, a small subpopulation of neostriatal neurons (1-2%) was Chol-1-positive. In the rat retina, both anti-Chol-1 and anti-choline acetyltransferase antibodies gave rise to a nerve terminal-like staining in the same bands within the inner plexiform layer. The anti-Chol-1 antibodies also stain normal and pathological human material and could have a useful application in human neuropathology.