Vascular responses to REN-293 (2-amino-3[3, 5-dihydroxyphenyl]-1-propanol hydrochloride)--a new sympathomimetic agent.

In this study the effects of REN-293 have been examined on the rat tail artery "in situ'. It was found that the drug was totally dependent on the sympathetic nerves for its vasoconstrictor action. This action was blocked by phentolamine and attenuated by pre-treatment of the vessel with tyramine. When a comparative study of the vasoconstrictor effects of several sympathomimetics was performed, it was found that REN-293 was more potent than tyramine and ephedrine, but less so than etilefrine. It would appear that REN-293 is of interest as a pharmacological tool for examining sympathetic nerve function, but its usefulness in the therapy of orthostatic hypotension is likely to be limited, due to the very indirect nature of its sympathomimetic action.