The effects on surface cholinesterases and contractility of intact cat irides treated with echothiophate iodide in vitro have been studied. Echothiophate, in contrast to diisopropylfluoro phosphate (DFP), more selectively inhibits true cholinesterases (ChE) than pseudo-ChE. Significant enzymatic inhibition is seen even with doses of echothiophate as low as 5 × 10-8 M, whereas DFP has little effect on these enzymes below 10-6 M concentration. The effects of echothiophate iodide on the acetyl-β-methylcholine dose-response curve and surface ChEs were completely reversed by in vitro treatment with pralidoxime chloride at 10-3 M.
Harris LS, Shimmyo M, Mittag TW. Cholinesterases and Contractility of Cat IridesEffect of Echothiophate Iodide. Arch Ophthalmol. 1973;89(1):49-51. doi:10.1001/archopht.1973.01000040051012