FACTORS AFFECTING THE SYNTHESIS OF ACETYLCHOLINE BY BRAIN SLICES

Abstract

The acceleration of the synthesis of ACh by rat brain slices by high K concn. was confirmed. At first, the rate tends to increase with time and synthesis continues at a high but variable rate for several hrs. Addition of ACh to the medium does not depress, but sometimes increases, the rate of synthesis. In the presence of high K concn., lack of Ca markedly inhibits ACh synthesis. Maximal synthesis occurs at about 1.3 m[image]. Ca, and further increase in Ca concn. is inhibitory. Mg has similar but much smaller effects. The CO2-bicarbonate buffer system is required for maximal synthesis. Any deviation from normal plasma concns. of CO2, bicarbonate, or H-ion, depresses synthesis. Pyruvate, oxaloacetate, and citrate, strongly inhibit synthesis in a glucose-containing medium.