Nippostrongylus brasiliensis: Infection induces upregulation of acetylcholinesterase activity on rat intestinal epithelial cells

Expression of cholinesterases and muscarinic acetylcholine receptors in the jejunal mucosa has been investigated during infection of rats with the nem atode parasite Nippostrongylus brasiliensis. Selective expression of m3 rec eptors was observed on epithelial cells from uninfected rats and animals 7 days postinfection, and saturation binding with [H-3]quinuclidinyl benzilat e indicated that receptor expression on cell membranes was unaltered by inf ection. Butyrylcholinesterase was highly expressed in mucosal epithelia, bu t acetylcholinesterase was present at low levels in uninfected animals. In contrast, discrete foci of intense acetylcholinesterase activity were obser ved on the basement membrane of intestinal epithelial cells in animals infe cted with N. brasiliensis. This was demonstrated to be due to upregulation of expression of endogenous enzyme, which peaked at Day 10 postinfection an d subsequently declined to preinfection levels. It is suggested that this o ccurs in response to hyper-activation of the enteric nervous system as a re sult of infection, and may benefit the host by limiting excessive fluid sec retion due to cholinergic stimulation. (C) 2000 Academic Press.