Abstract
The relation between the anti-cholinergic drugs and brain cholinesterase (ChE) activity was studied in vitro as well as in vivo, in which ChE activity was determined by titration after Hall & Lucas' method. Result : Atropine sulphate, choiced as one of the anticholinergics, does not promote the ChE activity by itself, nevertheless, it is recognizable that the ChE activity is protected from the inhibitory action of DFP, eserine, and prostigmine after atropine (10-3-10-4 : mol) either in vitro or in vivo, while atropine protects the ChE activity from the inhibitory action of DFP after DFP. Analogous protections are also proved in vitro in each case of the following anti-cholinergics : hyoscyamine, eumydrine, homatropine, scopolamine, mydriatine, trasentine, ephedrine, banthine, parpon, parpon methobromide, benadryl, and 3015 R.P., especially being remarkably observed by the administration of quaternary ammonium salt : eumydrine, banthine, and parpon methobromide. The other drugs tested, such as cocaine, tropacocaine, benzoylcholine, urethane, and pilocarpine, exert no protecting ability for the ChE activity from DFP. From the results obtained it is concluded that (1) anti-cholinergic drugs possesses more or less some protecting ability for the ChE activity and (2) such an ability plays an important role in the antagonism between ChE inhibitors and anti-cholinergics.
