Preventive Action of Cisternal Heparin Injection for Vasoconstriction After Experimental Subarachnoid Hemorrhage

We investigated the action of heparin in reducing the degree of vasoconstriction in the experimantal subarachnoid hemorrhage (SAH) models of rabbits. Heparin, injected intrathecally, reduced the degree of constriction significantly. On the other hand, systemic heparin injection or physiological saline cisternal injection did not reveal any preventive effect on constriction. From this experiment, we suppose that heparin might neutralize thrombin which was activated in the CSF after SAH and considered to be one of the constrictive factors producing vasospasm.