Epithelial distribution of neural receptors in the guinea pig small intestine

Abstract

Neural and paracrine agents, such as dopamine, epinephrine, and histamine, affect intestinal epithelial function, but it is unclear if these agents act on receptors directly at the enterocyte level. The cellular localization and villus-crypt distribution of adrenergic, dopamine, and histamine receptors within the intestinal epithelium is obscure and needs to be identified. Single cell populations of villus or crypt epithelial cells were isolated from the jejunum of adult guinea pigs. Enterocytes were separated from intraepithelial lymphocytes by flow cytometry and specific binding was determined using fluorescent probes. Alpha1-adrenergic receptors were located on villus and crypt intraepithelial lymphocytes and enterocytes. Beta-adrenergic receptors were found on villus and crypt enterocytes. Dopamine receptors were found on all cell types examined, whereas histamine receptors were not detected (<10% for each cell population). These studies demonstrated that (1) receptors for epinephrine and dopamine exist on epithelial cells of the guinea pig jejunum, (2) beta-adrenergic receptors are found primarily on villus and crypt enterocytes and (3) intraepithelial lymphocytes contain alpha1-adrenergic, but have few beta-adrenergic, receptors. The presence of neural receptors suggests that these agents are acting, at least in part, at the enterocyte or intraepithelial lymphocyte levels to modulate intestinal and immune function.

Expression of Bis in the mouse gastrointestinal system

“…The nerve terminals in the ENS could sense luminal contents, including nutrients via afferent fibers from mucosal cells, which contain specific chemoreceptors and initiate appropriate reactions, such as absorption, secretion and peristalsis [39, 40]. Moreover, the presence of receptors for small molecules, such as cholecystokinin, vasoactive intestinal peptide or nitric oxide, and receptors for peptide neurotransmitters, such as adregergic, cholinergic or dopaminergic receptors, have been demonstrated in the enteric epitheliums [41-45]. Finally, luminal perfusion studies with agonists and antagonists for adrengergic receptors indicate that the transport of glucose, amino acids or oligopeptide to enteric epithelial cells is, at least in part, under the neural control of intrinsic ENS [46-48].…”

Biogenic Amines: Signals Between Commensal Microbiota and Gut Physiology

“…Here, we provide a literature review of the expression of receptors of biogenic amines, especially focusing on intestinal epithelial cells. As summarized in Table 6, the expression of α1-adrenergic receptor on enterocytes was demonstrated by flow cytometry and binding assays (53, 54). Enterocytes from different species were also shown to harbor α2 adrenergic receptors, contributing to the net absorption of electrolytes and fluids (55–57).…”