Alpha-adrenergic activity of N,N-dimethyldopamine (DMDA).
The autonomic and cardiovascular activity of N,N-dimethyldopamine (DMDA) was studied in the dog and rabbit. DMDA appears to be a postganglionic sympathetic alpha-adrenoceptor agonist since it consistently caused vasconstriction in several isolated vascular beds, even in the presence of ganglionic blockade. The pressor activity of DMDA was attenuated by the alpha-adrenergic antagonist phentolamine. Calculated pA2 values for phentolamine against both DMDA and norepinephrine in isolated rabbit arteries were in close agreement. DMDA inhibits cardioaccelerator nerve stimulation induced chronotropic responses by a mechanism which appears to be alpha-adrenergic in the dog.
Alpha-adrenergic activity of N,N-dimethyldopamine (DMDA). The autonomic and cardiovascular activity of N,N-dimethyldopamine (DMDA) was studied in the dog and rabbit. DMDA appears to be a postganglionic sympathetic alpha-adrenoceptor agonist since it consistently caused vasconstriction in several isolated vascular beds, even in the presence of ganglionic blockade. The pressor activity of DMDA was attenuated by the alpha-adrenergic antagonist phentolamine. Calculated pA2 values for phentolamine against both DMDA and norepinephrine in isolated rabbit arteries were in close agreement. DMDA inhibits cardioaccelerator nerve stimulation induced chronotropic responses by a mechanism which appears to be alpha-adrenergic in the dog.