Acid-sensing ion channel 2 (ASIC2) in the intestine of adult zebrafish.

Acid-sensing ion channels (ASICs) in mammals monitor acid sensing and mechanoreception. They have a widespread expression in the central and peripheral nervous system, including the gut. The distribution of ASICs in zebrafish is known only in larvae and at the mRNA level. Here we have investigated the expression and cell distribution of ASIC2 in the gut of adult zebrafish using PCR, Western blot and immunohistochemistry. ASIC2 mRNA was detected in the gut, and a protein consistent with predicted ASIC2 (64kDa molecular mass) was detected by Western blot. ASIC2 positivity was found in a subpopulation of myenteric neurons in the enteric nervous system, as well in enteroendocrine epithelial cells. These data demonstrate for the first time the occurrence of ASIC2 in the gut of adult zebrafish where it presumably acts as a chemosensor and a mechanosensor.