Electrometric measurement of plasma and tissue cholinesterase activities of four wild birds in Iraq ASHRAF S. ALIAS and FOUAD K. MOHAMMAD* Department of Physiology, Biochemistry and Pharmacology, College of Veterinary Medicine, University of Mosul, P.O. Box 11136, Mosul, Iraq Abstract Determination of cholinesterase activity is an important tool for biomonitoring environmental exposure of wild birds to cholinesterase inhibiting pesticides such as organophosphates and carbamates. In the present study an electrometric method is described and used for measurement of cholinesterase activities in the plasma, brain, liver and pectoralis muscle of four indigenous wild birds commonly found in Northern Iraq. The birds examined were quail (Coturnix coturnix), large pin-tailed sand grouse (Perocles alchata caudacutus), starling (Sturnus vulgaris) and rock dove (Columba livia gaddi). The mean values of cholinesterase activity (ΔpH/30 min) in the plasma, brain, liver and pectoralis muscle of the birds were, respectively, as follows: quail (1.23, 0.39, 0.19 and 0.06), large pin-tailed sand grouse (1.81, 0.37, 0.06 and 0.07), starling (1.1, 0.24, 0.08 and 0.08) and rock dove (1.28, 0.59, 0.12 and 0.08). Using the technique of in vitro cholinesterase inhibition by quinidine sulfate, the estimated percentages of true cholinesterase activity in the plasma of the quail, large pin-tailed sand grouse, starling, and rock dove were 77, 69, 71 and 73%, respectively. These findings are the first report of plasma and tissue cholinesterase activities of the four wild birds in Iraq, using the described electrometric method. The electrometric values of cholinesterase activity of the wild birds could be used as reference points for future studies concerning biomonitoring of exposure of these birds to anticholinesterase pesticides.   < back .