Bulbocapnine's ability to antagonize the adrenergic inhibitory action of dopamine and analogs

Dopamine in the presence of cocaine, 5,6-dihydroxy-2-dimethylaminotetralin (M-7), apomorphine and N,N-dimethyldopamine produced dose dependent inhibition on the heart rate increase due to stimulation of the right cardioaccelerator postganglionic nerves. Inhibitory actions of these compounds were antagonized by bulbocapnine. Also bulbocapnine antagonized the blood pressure increase due to N,N-dimethyldopamine but did not antagonize the pressor response of dopamine.