Extracerebellar afferents of the cerebellar nuclei serotoninergic, noradrenergic, dopaminergic and peptidergic projections

EXTRACEREBELLAR AFFERENTS OF THE CEREBELLAR NUCLEI SEROTONINERGIC, NORADRENERGIC, DOPAMINERGIC AND PEPTIDERGIC PROJECTIONS 

Serotonin-like immunoreactivity resides in a fine network of varicose fibers in the neuropil of all cerebellar nuclei. This plexus is most dense in the hilar region of the lateral cerebellar nucleus of the rat (Takeuchi et al., 1982), among the small, intrinsic neurons of this region (Chan-Palay, 1977) and in the caudal and dorsal regions of the central nuclei of the opossum (Fig. 117) (Bishop et al., 1985). 

A heterogeneous population of terminals, containing large dense-core vesicles with a diameter of 900 A, were found to be labelled in the cerebellar nuclei after intraventricular infusions of H-serotonin in the rat. Few of these boutons show synaptic specializations (Chan-Palay, 1975, 1977). The ultrastructural morphology of nor- 

EM autoradiogram showing two climbing fiber boutons with spherical and pleomorphic vesicles, labelled from an injection with tritated leucine into the inferior olive make synaptic contact with a dendrite of a neuron of the fastigial nucleus of the cat. Van der Want and Voogd (1987). 

Neurons of the ventral tegmental area of the rat project to the cerebellar nuclei. These neurons do not contain tyrosine-hydroxylase and this projection, therefore, is non-dopaminergic, contrary to the projection of the dopaminergic AlO group located in the same area, to the cerebellar cortex of the rat (Ikai et al., 1992). 

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