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  • Innervation of enteric mast cells by primary spinal afferents in guinea pig and human small intestine.

Innervation of enteric mast cells by primary spinal afferents in guinea pig and human small intestine.

American journal of physiology. Gastrointestinal and liver physiology (2014-08-26)
Guo-Du Wang, Xi-Yu Wang, Sumei Liu, Meihua Qu, Yun Xia, Bradley J Needleman, Dean J Mikami, Jackie D Wood
ABSTRACT

Mast cells express the substance P (SP) neurokinin 1 receptor and the calcitonin gene-related peptide (CGRP) receptor in guinea pig and human small intestine. Enzyme-linked immunoassay showed that activation of intramural afferents by antidromic electrical stimulation or by capsaicin released SP and CGRP from human and guinea pig intestinal segments. Electrical stimulation of the afferents evoked slow excitatory postsynaptic potentials (EPSPs) in the enteric nervous system. The slow EPSPs were mediated by tachykinin neurokinin 1 and CGRP receptors. Capsaicin evoked slow EPSP-like responses that were suppressed by antagonists for protease-activated receptor 2. Afferent stimulation evoked slow EPSP-like excitation that was suppressed by mast cell-stabilizing drugs. Histamine and mast cell protease II were released by 1) exposure to SP or CGRP, 2) capsaicin, 3) compound 48/80, 4) elevation of mast cell Ca²⁺ by ionophore A23187, and 5) antidromic electrical stimulation of afferents. The mast cell stabilizers cromolyn and doxantrazole suppressed release of protease II and histamine when evoked by SP, CGRP, capsaicin, A23187, electrical stimulation of afferents, or compound 48/80. Neural blockade by tetrodotoxin prevented mast cell protease II release in response to antidromic electrical stimulation of mesenteric afferents. The results support a hypothesis that afferent innervation of enteric mast cells releases histamine and mast cell protease II, both of which are known to act in a diffuse paracrine manner to influence the behavior of enteric nervous system neurons and to elevate the sensitivity of spinal afferent terminals.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
Anti-Tryptase Antibody, Mast Cell, clone G3, clone G3, Chemicon®, from mouse
Supelco
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Capsaicin, European Pharmacopoeia (EP) Reference Standard
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Anti-S-100 antibody produced in rabbit, IgG fraction of antiserum, buffered aqueous solution
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Capsaicin, ≥95%, from Capsicum sp.
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Anti-Chymase Antibody, clone B7, clone B7, 2.4 mg/mL, Chemicon®
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Anti-Calcitonin Gene Related Peptide Antibody, α hCGRP a.a. 28-37, clone CD8, clone CD8, Chemicon®, from mouse
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Capsazepine, ≥98% (HPLC), solid
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