[The experimental study of the cerebral vasospasm--the micro-circulation on the hypothalamus and the brain stem...

The correlation between the cerebral vasospasm and the micro-circulation in the hypothalamus and brainstem was observed histologically and electronmicroscopically using the colloidal carbon infusion method through the right vertebral artery of dogs. The posterior communicating artery of the dog was ruptured with a fine needle, which resulted in subarachnoid hemorrhage. The colloidall infusion was done at 30 min., 48 hours, 1 week and 4 weeks after the subarachnoid hemorrhage. Results 1) The cerebral vasospasm was confirmed by vertebral angiography on all cases with 30 min., 48 hours, and 1 week after the subarachnoid hemorrhage., In 1 case out of 5 with 4 weeks after subarachnoid hemorrhage vasospasm was also observed. 2) In the period of early spasm, ischemic changes were observed in the anterior-hypothalamus especially in periventricular area of the 3rd ventricle, and supraoptic nucleus. 3) In the period of late spasm, the ischemic changes in the hypothalamus became more conspicous, and these changes propagated into the tectal region of the midbrain and the central gray substance of the aqueduct. 4) In cases of 4 weeks after subarachnoid hemorrhage the ischemic change similar to cases listed in 3) was observed in 1 case whose angiography showed vasospasm. Another 4 cases showed no ischemic lesion at all. 5) Electron microscopic study showed the vasogenic edema in the hypothalamus in the case with cerebral vasospasm. There might be the possibility that vasomoter mechanism in the hypothalamus and brainstem would be involved with the vasogenic edema produced by cerebral vasospasm, which in turn would give a bad influence upon the spasmogenic vessels.