Distinct cellular expression of pertussis toxin-sensitive GTP-binding proteins in rat cerebellum

Abstract

Immunohistochemical localization of pertussis toxin-sensitive GTP-binding proteins in rat cerebellum was investigated using antibodies raised against purified G αo and synthetic peptides corresponding to specific sequences of G αi1, G αi2 and G αi3. G αo was detected mostly in the molecular layer but not in the cell body of the Purkinje cells. G αi1 and G αi2 were found predominantly in the molecular layer and in addition in the cell body of the Purkinje cells. G αi3 was not detected in rat cerebellum. Immunoblot analysis demonstrated that in the cerebellum membrane G α0 was most abundant and surprisingly the amount of G αi2 was much higher than that of G αi1. Thus, each pertussis toxin substrate was found to be expressed differently in rat cerebellum. The different patterns of expression imply that each subtype of GTP-binding proteins may have a specific function in modulating the neuronal activity in rat cerebellum.