Non-competitive inhibition of serum acetylcholinesterase (E.C.3.1.1.7) by vacor (N-3-pyridyl methyl-N'-P-nitrophenyl urea) in bandicoot rats.

Single dose (1 mg/rat) administration of VACOR (N-3-pyridyl methyl-N'-nitrophenyl urea) produced significant paralytic symptoms in rats. Such rats which lived for one week were sacrificed and serum AChE was extracted and purified by Sephadex column chromatography. The serum enzyme from the normal rats showed the existence of two isozymes on polyacrylamide gels which could be resolved through column chromatography. Both the isozymes showed non-competitive inhibition with VACOR in vitro; but to a varied degree. The ACh concentration increased by 70-75% in serum and 95-100% in erythrocytes of the poisoned rats. VACOR thus affects ACh hydrolysis thereby causing an accumulation of ACh in the serum of poisoned rats.