Japanese quail acute exposure to methamidophos: Experimental design, lethal, sub-lethal effects and cholinesterase biochemical and histochemical expression

► We examined the effects of methamidophos to Japanese quail in an acute oral test. ► We estimated ChE activity in various tissues using various substrate-inhibitors. ► Changes concerning the activity of plasma, brain and liver ChEs, were reversible. ► Cyto-architectural and histochemical changes were persistent. ► We assessed enteric neuronal function in a major absorption site, the duodenum.