ABSTRACT
Studies of the pathophysiology of intracranial artery following vasospasm remains yet incomplete. The present investigation was undertaken for the purpose of elucidating ultrastructural changes in the cerebral arterial wall sequentially from 1 hour to 24 hours following subarachnoid hemorrhage. Experimental vasospasm was induced by injecting autogenous blood into the cisterna magna of cats. The following observations were made : 1) One hour after the induction of subarachnoid hemorrhage, endothelial cells in the intima became more round and their cellular surface was markedly corrugated, these changes culminated at 7 to 24 hours with intimal thickening(due to subendothelial tissue). 2) In the media, the smooth muscle cells were most consistently and severly affected showing degeneration of mitochondria and vacuoles containing fine particles. 3) Twelve hours following SAH, some endothelial cells in the intima were displaced or seemed to have partially broken apart from the adjoining cells. On the basis of the above findings, it was concluded that the ultrastructural changes in the cerebral arterial wall was observed after the induction of SAH with normal cat's blood occurred as a consequence of vasospasm of the intracranial arteries.