Effect of physostigmine on cholinesterase activity in different parts of rat brain.

Inhibition of acetylcholinesterase (AChE) in the whole brain, cerebellum, pons, frontal cortex, basal ganglia and medulla oblongata of rat brain by physostigmine (CAS 57-47-6) in vitro was studied. Constants characterizing this inhibition namely: binding constant (KI) and bimolecular rate constant (K'2) were determined. The highest values of K'2 were obtained in the cases of pons and medulla oblongata, the parts responsible for the respiratory and vital centers. The difference in the inhibition of AChE in the different parts of the brain could be due to the difference in the grey and white matters contents in these parts.