Abstract
In vitro experiments were carried out to determine the inhibitory effects of several agents, especially a Ca++ -blocker, nifedipine, on hemoglobin-induced contractions of dog basilar arteries.
Agents tested included methysergide, phentolamine, mepyramine, and aspirin. None of these agents significantly inhibited hemoglobin-induced contractions. This indicates that serotonin, norepinephrine, histamine, and prostaglandins are not involved in the contractile activity of hemoglobin. The inhibitory effect of cyclic AMP on hemoglobin-induced contractions was slight even at high concentrations.
In Ca++-free solution, basilar arteries showed no response to hemoglobin. Nifedipine was found to be a highly potent inhibitor of hemoglobin-induced contractions. The inhibitory effect of nifedipine on hemoglobin-induced contractions was greater than that of papaverine.
These data suggest that nifedipine might be useful in the treatment of vasospasms following rupture of an aneurysm.
