Effect of CDP-choline on brain acetylcholinesterase and Na+,K+-ATPase in adult rats

Objective: The aim of this work was to investigate the effect of different cytidine-5'-diphosphocholine (GDP-choline) concentrations(0.1-1 mM) on acet ylcholinesterase (AChE), (Na+,K+)-ATPase and Mg2+-ATPase activities in homo genates of adult rat whole brain and in pure (nonmembrane bound) enzymes. Design and Methods: Tissues were homogenized, centrifuged at 1000 X g for 1 0 min, and in the supernatant AChE activity and Na+,K+-ATPase, Mg2+-ATPase activities were determined according to Ellman's method and Bowler's and Ti rri's, respectively. Results: After a 1-3 h CDP-choline preincubation, this substance induced a maximal stimulation of 20%-25% (p < 0.001) for AChE and 50-55% (p < 0.001) for Na+,K+-ATPase, but it did not influence Mg2+-ATPase activity. One mM ac etylcholine (ACh) resulted in an approximately 18% (p < 0.001) AChE inhibit ion by excess substrate in the brain homogenate, while 0.01 mM noradrenalin e did not influence Na+,K+-ATPase activity. Conclusions: CDP-choline can stimulate brain AChE and Naf,K+ ATPase indepen dently of ACh and noradrenaline. This enzymatic stimulation may be due to t he transformation of GDP-choline to membrane phophatidylcholine. The above data could explain in part the clinical effects of this substance in some n euronal disturbances. Copyright (C) 2000 The Canadian Society of Clinical C hemists.