Physiologically Induced Alteration of Sulfate Penetration Into Brain

Abstract

THE MEASUREMENT of local cerebral blood flow using the principles of inert gas exchange between blood and tissue has been described by Kety.^1,2 The radioactive inert gas trifluoroidomethane (CF₃I¹³¹) has been used to map blood flow in the various regions of the cat brain in both the conscious and the anesthetized animal. With CF₃I¹³¹ the effect of increased functional activity on local blood flow has also been demonstrated. Sokoloff³ showed an increased autoradiographic density in the striate cortex and the lateral geniculate ganglia demonstrating an increased blood flow to these structures after photic stimulation. The usefulness of the inert gases in the evaluation of blood flow depends upon their free diffusibility from the vascular bed. Thus this characteristic of the gas, which is essential for the measurement of blood flow, makes CF₃I¹³¹ inadequate as a measure of local changes