Increase in ACh Release from the Rat Brain Cortex Slices by 3’,5’-Cyclic Adenosine Monophosphate

Abstract

ACh released into the medium during incubation for 15 min was estimated with eserinized abdominal muscle of Rana pipiens according to the method of Chang and Gaddum. The amount of ACh released from the rat brain cortex slices was increased by addition of 5 mM dibutyryl cyclic [c] AMP and 1 mM theophylline, although theophylline did not increase ACh release. Dibutyryl cAMP alone showed a stimulatory effect on the ACh release, but the effect seemed variable. The effect of dibutyryl cAMP on the slices immersed in high K+ medium was examined. The stimulatory effect of dibutyryl cAMP was observed also in the depolarized state, but its effect was not strengthened by a high K+ medium. cAMP may increase ACh release from the nerve endings of the CNS in a manner similar to the release from motor nerve endings.