THE MECHANISM OF ACTION OF ANTICHOLINESTERASE COMPOUNDS ON THE PATELLAR REFLEX

¹ Pharmacology Branch, Chemical Corps Medical Laboratories, Army Chemical Center, Maryland

A correlation has been attempted between the effects of DFP and TEPP on a spinal reflex and on the acetylcholine and cholinesterase concentrations within the central nervous system. Biopsies of cat brain and of rat brain and spinal cord were taken (1) before poisoning while the knee-jerk was functional; (2) after poisoning when the reflex was absent; (3) later after the reflex reappeared and again after (4) cessation and during (5) recovery produced by a second dose of the poison. The acetylcholine and cholinesterase levels of the nervous tissue during these five periods were determined. There was a decrease in cholinesterase and an increase in free acetylcholine in sample 2, but functional changes thereafter did not correlate with changes in cholinesterase or acetylcholine. These results suggest that the effects of DFP and TEPP on the knee-jerk can involve actions other than inhibition of cholinesterase in the central nervous system.