In vivo and in vitro effects of phospholine iodide on cat iris

The effects of phospholine iodide on the true and pseudo cholinesterases of cat iris were studied by administering this drug in drop form to cat eyes and by incubating cat irides in vitro with the identical drug. After both in vivo and in vitro administration, phospholine iodide was found to more significantly inhibit the true cholinesterases than the pseudo enzyme of cat iris. Maximum enzymatic inhibition after in vivo administration was found after the first day of drug administration, and did not increase even after administering this drug for five consecutive days. Significant inhibition of cholinesterases was also found in the untreated eye of experimental animals. This observation stresses the necessity for using separate animals as controls when studying the effects of drugs in small animals.