The convulsive action of pentylenetetrazol and electroshock in irradiated rats

Convulsive activity of pentylenetetrazol and electroshock was measured in rats irradiated 24 hr earlier with 800 R of X rays. At this time the content of "free" acetylcholine (ACh) was increased in the cerebral cortex, and the content of "bound" ACh was depressed in the brain stem. Irradiation facilitated the action of convulsogenic agents. Atropine did not prevent convulsions but facilitated them. An increase in the endogenous pool of ACh by eserine similarly to atropine facilitated the action of convulsogenic agents in control rats. In irradiated rats eserine shortened the duration of electrogenic convulsions, but it did not change significantly the latency of pentylenetetrazol convulsions. A causal relationship between the effects observed and post-irradiation modification of the content of "free" and "bound" ACh in the cerebral cortex and brain stem is discussed.