MODIFICATIONS OF A CHOLINESTERASE METHOD FOR DETERMINATION OF ERYTHROCYTE CHOLINESTERASE ACTIVITY IN WILD MAMMALS

A method to determine erythrocyte cholinesterase (ChE) activity was mo dified for use in wild mammals. Erythrocyte ChE of California voles (M icrotus californicus) was primarily acetylcholinesterase (AChE), which was similar to the brain and unlike plasma which was primarily butyry lcholinesterase (BChE). Triplicate erythrocyte AChE analyses from indi vidual animals of several species of wild rodents revealed a mean coef ficient of variation of 8.7% (SD = 4.3%). Erythrocyte ChE activity of several wild mammals of California revealed that mule deer (Odocoileus hemionus) had the highest erythrocyte AChE activity (1,514.5 mU/ml) a nd dusky-footed woodrats (Neotoma fuscipes) had the lowest activity (5 24.3 mU/ml). No ChE activity was found in erythrocytes of several spec ies of birds and fish.