[Possible participation of potassium ions in the regulation of local cerebral blood flow].

The microinjections of mock spinal fluid with various potassium concentrations into the cat and monkey brain tissue were made in acute and chronic experiments. The vascular reactions as studied with the microphotography and H-clearance method were found to be linearly related to the potassium concentrations within the range of 0--12 mEq/1, being constrictory below 5 mEq/1 and dilatory above that. An interaction between MSF potassium and pH seems to be weak if any, since the slope of the potassium vascular activity diagram remains unchanged within 6.8--7.8 pH change. The data obtained suggest that potassium ions take part in rCBF control since potassium is known to escape from stimulated nerve cells and thus substantially increase an extracellular potassium concentration.