Investigation of the dependence of human middle cerebral artery contractile activity on the presence of an atherosclerotic patch.

In some cases, human middle cerebral artery segments reacted to vasoconstrictor stimuli, including noradrenaline, KCL, prostaglandin F2 alpha, and activated platelets and neutrophils, by showing abnormally long-term contraction. All the segments were atherosclerotic, the atherosclerotic patch constricting the lumen to 30%-50%. Vasodilator concentrations that remove the ordinary contraction of vessels, only slightly limited the abnormal spastic reaction. A positive interaction between nifedipine and prostacyclin was revealed, and their combined use had a more marked anti-spasmatic effect than when these agents were used separately.