Validation of an electrometric blood cholinesterase measurement in goats.
A modified electrometric method was described and validated for measurement of plasma and erythrocyte cholinesterase activities in 6-18 months old goats. The enzymatic reaction mixture contained 3 ml distilled water, 3 ml barbital-phosphate buffer (pH 8.1), 0.2 ml plasma or erythrocytes and 0.1 ml acetylthiocholine iodide (7.5%) as a substrate. The mixture was incubated at 37 degrees C for 40 minutes. The pH of the reaction mixture was determined by a pH meter before and after the incubation. The initial pH was measured before the substrate addition. The enzyme activity was expressed as DeltapH/40 min. The coefficients of variation of the described method in measuring plasma and erythrocyte cholinesterase activities were 4 and 2%, respectively. Preliminary reference values (n = 14) of the mean cholinesterase activity (DeltapH/40 min) and 95% confidence interval in the plasma were 0.194 and 0.184-0.204, respectively, and those of the erythrocytes were 0.416 and 0.396-0.436, respectively. The pseudocholinesterase activity of the plasma cholinesterase was 63.5% as determined by quinidine sulfate inhibition. The organophosphorus insecticides dichlorvos and diazinon at 0.5-4 microM and the carbamate insecticide carbaryl at 5-20 microM in the reaction mixture significantly inhibited plasma (13.7-85.5%) and erythrocyte (16.4-71.9%) cholinesterases in vitro in a concentration-dependent manner. The results suggest that the described electrometric method is simple, precise and efficient in measuring blood cholinesterase activity in goats.
Al-Jobory
M M H
MM
Department of Physiology, Division of Pharmacology and Toxicology, College of Veterinary Medicine, University of Mosul, Mosul, P. O. Box 11136, Iraq.
Mohammad
F K
FK
D000136:Acid-Base Equilibrium / Q000502:physiology; D000818:Animals; D012721:Carbaryl / Q000494:pharmacology; D002800:Cholinesterase Inhibitors / Q000494:pharmacology; D002802:Cholinesterases / Q000097:blood* / Q000187:drug effects; D003976:Diazinon / Q000494:pharmacology; D004006:Dichlorvos / Q000494:pharmacology; D004789:Enzyme Activation / Q000187:drug effects / Q000502:physiology; D004912:Erythrocytes / Q000378:metabolism; D006041:Goats / Q000097:blood*; D010949:Plasma / Q000378:metabolism
D002800:Cholinesterase Inhibitors; D004006:Dichlorvos; D002802:Cholinesterases; D012721:Carbaryl; D003976:Diazinon