| Popis: |
It is generally accepted that physiologic autonomic and humoral influences which evoke powerful reactions in the peripheral circulation hardly affect that of the brain. Evidence is accumulating, however, that high concentrations of biogenic amines are capable of eliciting changes in cerebrovascular caliber, and that autonomic nerves may serve to modulate the response of cerebral vessels to more potent stimuli (5, 7). In addition, experimental blood-induced basilar artery spasm has been reversed by α-adrenergic blockers (2). |
