Calcitonin gene-related peptide-like immunoreactivity in neuronal elements of the cat cerebellum

Calcitonin gene-related peptide-like immunoreactivity (CGRP-LI) was found in many mossy fiber endings in the cat cerebellum. Some fine varicose fibers within the cerebellar nuclei also showed CGRP-LI. By injecting colchicine into the lateral ventricle of the cerebrum, CGRP-LI was further visualized in perikarya of many granule cells and some small neurons in the dentate and interpositus nuclei. Among the brainstem precerebellar nuclei, the largest number of neuronal cell bodies with CGRP-LI was found in the pontine nuclei. When a lesion was placed in the pontine brachium, mossy fiber endings with CGRP-LI reduced in number in the cerebellar hemisphere of the posterior lobe ipsilateral to the lesion. Fine varicose fibers with CGRP-LI within the dentate nucleus were also decreased in number ipsilaterally to the lesion. Thus, the majority of fiber endings with CGRP-LI in the hemisphere of the posterior lobe and the dentate nucleus of the cerebellum were assumed to originate from the contralateral pontine nuclei.