Transient Metabolic and Vascular Volume Changes Following Rapid Blood Pressure Alterations Which Precede the Autoregulatory Vasodilation of Cerebrocortical Vessels

Abstract

Cerebral blood flow (CBF) is autoregulated which means that the flow does not change significantly in the range of arterial blood pressure of 50–200 mmHg (Harper 1966). Although great efforts have been devoted to understanding CBF autoregulation, its exact mechanism is till unknown. Fog (1937) showed that the diameter of the pial arteries first decreases and later increases after a transient decrease of arterial blood pressure. Since this initial observation not much attention has been devoted to the biphasic nature of the alterations in diameter of the pial vessels evoked by a rapid drop in arterial blood pressure. The present study was mainly focused on the transitory changes of cerebro-cortical vascular volume and NAD-NADH redox state during a rapid decrease of arterial blood pressure. The other aim of our study was to investigate the effect of phenoxybenzamine on these vascular and metabolic changes.