Molecular keys to the problems of cerebral vasospasm

THE MECHANISMS RESPONSIBLE for subarachnoid hemorrhage (SAH)-induced vasosp asm are under intense investigation but remain incompletely understood. A c onsequence of SAM-induced vasospasm, cerebral infarction, produces a nonrec overable ischemic tissue core surrounded by a potentially amenable penumbra . However, successful treatment has been inconsistent. In this review, we s ummarize the basic molecular biology of cerebrovascular regulation, describ e recent developments in molecular biology to elucidate the mechanisms of S AH-induced vasospasm, and discuss the potential contribution of cerebral mi crocirculation regulation to the control of ischemia. Our understanding of the pathogenesis of SAH-induced vasospasm remains a major scientific challe nge; however, molecular biological techniques are beginning to uncover the intracellular mechanisms involved in vascular regulation and its failure. R ecent findings of microvascular regulatory mechanisms and their failure aft er SAH suggest a role in the development and size of the ischemia. Progress is being made in identifying the various components in the blood that caus e SAH-induced vasospasm. Thus, our evolving understanding of the underlying molecular mechanism may provide the basis for improved treatment after SAH -induced vasospasm, especially at the level of the microcirculation.