Immunocytochemical Study on the Distribution Pat- tern of Corticotropin Releasing Factor and Norepi- nephrine in the Middle Lobe of Monkey Cerebellum

= Abstract = Immunocytochemical methods, employing a specific antiserum against human corticotropin releasing factor (CRF) and dopamine beta hydroxylase, were applied to investigate the distribution pattern of CRF and norepinephrine fibers in the cerebellar cortex of squirrel monkey. CRF fibers were present mainly in the molecular layer throughout the major regions of cerebellar cortex. Howeeer, the most intensely labeled axons were strikingly clustered within particular regions and parasagittal domains. In the vermis and intermediate zone, intensely labeled axons were present only within parasagittal zones similar in location to those defined by climbing fiber innervation from the medial accessory olive, Intensely labeled axons were also densely but uniformly distributed within the uvula, the medial region of the dorsal paraflocculus, and the dorsal region of the pyramis, areas that recetee their climbing input primarily from the medial accessory olive. Labeled fibers were much less dense and were not clustered in the lateral hemispheres. Norepinephrine fibers were found throughout the cerebellar cortex, and the prominent population of norepinephrine fibers in cerebellar cortex was localized within the granular layer and Purkinje cell layer. In the vermis, the great density is seen in posterior lobules, especially lobules VII-X In the hemispheric region, a dense plexus of norepinephrine fibers was present throughout the granule cell layer, and the immunoreactive density in this region was greater than the density in the vermis. These results indicate that (l) CRF is the main neurotransmitter in the molecular layer and norepinephrine is the important transmitter in the granular layer (2) there were significant differences in the laminar distribution in different lobules of the cerebellum between CRF and norepinephrine.