THE SUBCELLULAR LOCALIZATION OF CARBAMYLCHOLINE‐STIMULATED PHOSPHATIDYL INOSITOL TURNOVER IN RAT CEREBRAL CORTEX <i>IN VIVO</i>

Abstract

Abstract— The intraventricular injection of 40 μCi of 32 P i (carrier free) into adult rats resulted in maximum incorporation of 32 P i into the phosphatidyl inositol of the whole cortex after 20 h. A further intraventricular injection of 2 nmol carbamylcholine plus 0.02 nmol eserine resulted in a 23% decrease in the specific activity of phosphatidyl inositol after 20 min. The specific radioactivities of phosphatidyl choline, phosphatidyl ethanolarmine and phosphatidyl serine were not changed. Cerebral cortex from rats treated in this way was subjected to an extensive subcellular fractionation. It was found that the specific radioactivity of the phosphatidyl inositol of the synaptic vesicle fraction showed a reduction of 60%. No other fractions showed effects of this magnitude.