Ouabain antagonism of noradrenaline inhibitions of cerebellar purkinje cells and dopamine inhibitions of caudate neurones

Abstract

As a test of the hypothesis that catecholamines exert their inhibitory effects on neuronal activity via stimulation of an electrogenic ion pump, the ability of iontophoretically applied ouabain, a known inhibitor of neuronal Na-K adenosine triphosphatase, to antagonize noradrenaline and γ-aminobutyric acid inhibitions of Purkinje cells and dopamine and γ-aminobutyric acid inhibitions of caudate cells was examined. Ouabain exhibited antagonistic activity toward amine inhibitions on both types of cells while leaving the amino acid inhibition intact. The results are interpreted as being consistent with a “pump” hypothesis of catecholamine inhibition of neuronal excitability.