Open AccessCholinergic-induced anion secretion in murine jejunal enteroids involves synergy between muscarinic and nicotinic pathways
Author(s) -
Kelli Johnson,
Jianyi Yin,
Julie In,
Subhash Kulkarni,
Pankaj J. Pasricha,
Chung Ming Tse,
Mark Donowitz
Publication year - 2020
Publication title -
american journal of physiology. cell physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.432
H-Index - 181
eISSN - 1522-1563
pISSN - 0363-6143
DOI - 10.1152/ajpcell.00179.2020
Subject(s) - hexamethonium , nicotinic agonist , muscarinic acetylcholine receptor , muscarinic antagonist , endocrinology , carbachol , muscarinic acetylcholine receptor m3 , medicine , chemistry , cholinergic , bethanechol , nicotinic antagonist , acetylcholine , biology , microbiology and biotechnology , receptor , biochemistry
Acetylcholine induces robust electrogenic anion secretion in mammalian intestine and it has long been hypothesized that it mediates the epithelial response through the M 3 and, to a lesser extent, the M 1 muscarinic receptors in the mouse. However, nicotinic receptors have recently been identified in intestinal enterocytes by quantitative real-time (qRT)-PCR/RNAseq, although any direct influence on intestinal transport has not been identified. We tested the hypothesis that cholinergic-induced anion secretion in the intestine is a result of both muscarinic and nicotinic pathways that are intrinsic to the intestinal epithelia. We developed a method to generate mouse jejunal enteroid monolayers which were used to measure active electrogenic anion secretion by the Ussing chamber/voltage-clamp technique. Here, we show that the cholinergic agonist carbachol (CCh) and the muscarinic agonist bethanechol (BCh) stimulate short-lived, concentration-dependent anion secretion in the epithelial cell-only enteroid monolayers. The muscarinic antagonist atropine completely inhibited CCh- and BCh-induced secretion, while the nicotinic antagonist hexamethonium reduced the CCh response by ~45%. While nicotine alone did not alter anion secretion, it increased the BCh-induced increase in short-circuit current in a concentration-dependent manner; this synergy was prevented by pretreatment with hexamethonium. In addition to being sensitive to hexamethonium, monolayers express both classes of cholinergic receptor by qRT-PCR, including 13 of 16 nicotinic receptor subunits. Our findings indicate that an interaction between muscarinic and nicotinic agonists synergistically stimulates anion secretion in mouse jejunal epithelial cells and identify a role for epithelial nicotinic receptors in anion secretion.