Cardiac denervation supersensitivity produced in guinea pigs by 6-hydroxy-dopamine.

The effects of chemical sympathectomy with 6-hydroxydopamine (6-OH-DA) on the sensitivity of guinea-pig heart to catecholamines were studied. Heart rate at rest and chronotropic effects of catecholamines remained unchanged after chemical sympathectomy, while the arrhythmogenic effects of epinephrine, norepinephrine and isoprenaline were potentiated markedly. Our results indicate that chemical sympathectomy with 6-OH-DA produced post synaptic denervation supersensitivity in the heart ventricles.