MODULATION OF NEURONAL-ACTIVITY OF CEREBELLAR FASTIGIAL NUCLEUS BY LOCUS-COERULEUS STIMULATION IN THE RAT

The effects of stimulating locus coeruleus (LC) on neuronal activity o f cerebellar fastigial nucleus (FN) was investigated. Stimulation of L C elicited inhibitory, excitatory and biphasic (inhibition-excitation) responses from FN cells. The majority of responsive cells showed an i nhibitory response with a latency of less than 10 ms. Injection of a a drenoreceptor antagonists phentolamine ( IV) could block the inhibitor y response of FN cells to the LC stimulation, but propranolol (IV), a beta adrenoreceptor antagonist, could not. These results suggest that LC-cerebellar noradrenergic afferent fibers may be involved in the cer ebellar sensorimotor integration process by exerting their modulatory action on the cerebellar nuclear cells' activities.