Comparison of the oxime-induced reactivation of rhesus monkey, swine and guinea pig erythrocyte acetylcholinesterase following inhibition by sarin or paraoxon, using a perfusion model for the real-time determination of membrane-bound acetylcholinesterase activity.
Recently, a dynamically working in vitro model with real-time determination of membrane-bound human acetylcholinesterase (AChE) activity was shown to be a versatile model to investigate oxime-induced reactivation kinetics of organophosphate- (OP) inhibited enzyme. In this assay, AChE was immobilized on particle filters which were perfused with acetylthiocholine, Ellman's reagent and phosphate buffer. Subsequently, AChE activity was continuously analyzed in a flow-through detector. Now, it was an intriguing question whether this model could be used with erythrocyte AChE from other species in order to investigate kinetic interactions in the absence of annoying side reactions. Rhesus monkey, swine and guinea pig erythrocytes were a stable and highly reproducible enzyme source. Then, the model was applied to the reactivation of sarin- and paraoxon-inhibited AChE by obidoxime or HI 6 and it could be shown that the derived reactivation rate constants were in good agreement to previous results obtained from experiments with a static model. Hence, this dynamic model offers the possibility to investigate highly reproducible interactions between AChE, OP and oximes with human and animal AChE.
Bundeswehr Institute of Pharmacology and Toxicology, Neuherbergstrasse 11, 80937 Munich, Germany.
Nadja M
NM
Herkert
Guy
G
Lallement
Didier
D
Clarençon
Horst
H
Thiermann
Franz
F
Worek
D000110:Acetylcholinesterase / Q000378:metabolism*; D000818:Animals; D002800:Cholinesterase Inhibitors / Q000494:pharmacology*; D002801:Cholinesterase Reactivators / Q000494:pharmacology*; D004789:Enzyme Activation / Q000187:drug effects; D004912:Erythrocytes / Q000201:enzymology*; D006168:Guinea Pigs; D007700:Kinetics; D008253:Macaca mulatta; D008297:Male; D010091:Oximes / Q000494:pharmacology*; D010261:Paraoxon / Q000494:pharmacology*; D010477:Perfusion; D012524:Sarin / Q000494:pharmacology*; D034421:Sus scrofa
D002800:Cholinesterase Inhibitors; D002801:Cholinesterase Reactivators; D010091:Oximes; D012524:Sarin; D000110:Acetylcholinesterase; D010261:Paraoxon