Noradrenaline modulation of the responses of the cerebellar Purkinje cell to afferent synaptic activity.

Noradrenaline, applied by microiontophoresis to rat cerebellar Purkinje neurones, selectively depressed spontaneous neuronal discharge. Simple spike and complex spike excitations, evoked by stimulation of the mossy and climbing fibres, were relatively preserved during the inhibition of spontaneous activity, and the number of full-sized action potentials in the complex spike increased. Inhibition mediated by the basket and stellate cells was augmented. Thus, relative to the change in spontaneous activity, noradrenaline increased the responsiveness of the Purkinje cell to afferent input.