Exposure to organophosphate (OP) chemical warfare agents (CWAs), pesticides, anesthetics, drugs such as cocaine, and a variety of therapeutic drugs including donepezil or rivastigmine for Alzheimer's disease reduces red blood cell acetylcholinesterase (RBC-AChE) or serum butyrylcholinesterase (BChE) activity. The activity of RBC-AChE and BChE can be used as potential biomarkers of suppressed and/or heightened function in the central and peripheral nervous systems. For instance, the toxicity of pesticides is well ...