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
