Modulation of cerebellar CGRP binding sites induced by climbing fibre activation

The neuropeptide CGRP is transiently expressed at neonatal stages in the rat olivocerebellar system, while high affinity binding sites for the peptide are permanently expressed in the molecular layer of the adult cerebellum. In this study, an increase in the density of cerebellar high affinity binding sites for calcitonin gene-related peptide (CGRP) is induced by harmaline, given at a dose appropriate to induce tremor. The present results, taken together with the demonstration that harmaline is a potent stimulator of the olivocerebellar system, suggest that the expression of cerebellar CGRP receptors can be modulated by the level of activity in the cerebellar afferents.