Butyrylcholinesterase distribution in the mouse gastrointestinal tract: An immunohistochemical study

Butyrylcholinesterase (BChE) is a hydrolytic enzyme that together with acetylcholinesterase (AChE) belongs to the cholinesterase family. Whereas AChE has a well‐established role in regulating cholinergic neurotransmission in central and peripheral synapses, the physiological role of BChE remains elusive. In this morphological immunohistochemical and double‐label confocal microscopy study we investigated the distribution of BChE in the mouse gastrointestinal tract. BChE‐positive cells were detected in the liver (both in hepatocytes and cholangiocytes), in the keratinised layers of the squamous epithelium of the oesophagus and forestomach, in the oxyntic mucosa of the stomach, in the mucus‐secreting cells of duodenal Brunner glands and the small and large intestinal mucosa. Interestingly, BChE‐positive cells were often detected close to gastrointestinal proliferative niches. In the oxyntic mucosa, the close proximity of ghrelin‐producing and BChE‐positive parietal cells suggests that BChE may be involved in ghrelin hydrolysation through paracrine action. To our knowledge, this is the first comprehensive morphological study performed to gain insight into the physiological role of BChE in the gastrointestinal tract.