Kinins and central effects of the acetylcholine.

The interaction between kinins formed in central nervous system and acetylcholine was studied. Endogenous ACh in excess acted psychodepressively on the animal's behavior as evaluated with Lat's test. This effect was more intense in those rats in which the activity of kinin-forming enzymes in the nervous tissue had been increased with either kallikrein or bradykinin. Both kallikrein and bradykinin intensified the psychodepressive action of exogenous ACh given into the brain ventricle. Results show that kinins can enhance the inhibitory central action of ACh.