Immunocytochemical localisation of caligulin-like immunoreactivity in rat tissues

The cellular localisation of caligulin-like immunoreactivity (caligulin-LI) in rat central and peripheral tissues was studied using antibodies against bovine brain caligulin raised in rabbits. Both immunofluorescence and immunoperoxidase techniques were used to demonstrate caligulin-LI in paraformaldehyde fixed tissues. Certain neurons in the cerebral cortex, basal ganglia and brain stem contained caligulin-LI. In the cerebellum a majority of Purkinje cells were labelled with immunoreactive material localised to dendrites, perikarya and axons. In the gastrointestinal tract some neurons in Auerbach's and Meissner's plexa contained caligulin-LI. Ligation of the sciatic nerve caused accumulation of immunoreactive material both proximal and distal to the crush. A non-neuronal localisation of caligulin-LI could also be demonstrated, e.g., in parts of the renal tubular system, in the islets of Langerhans and in certain enteroendocrine cells. The specific localisation of caligulin-LI in some but not all neurons of the rat brain and gastrointestinal tract suggests a specific function of caligulin in central and peripheral nervous mechanisms.