Carbachol stimulation of gastric acid secretion and its effects on the parietal cell

Abstract

1 The acid secretagogue eect of gastrin is mainly mediated by the release of enterochroman-like (ECL) cell histamine, but the mechanism of muscarinic stimulation of acid secretion remains unclear. The results of studying aminopyrine uptake in isolated parietal cells, and histamine release in isolated ECL cells suggest that muscarinic agents may act both directly on the parietal cell and indirectly via histamine release from ECL cells. 2 We examined parietal and ECL cell responses to the muscarinic agent carbamylcholine (carbachol) in conscious rats and in rat isolated vascularly perfused stomachs. 3 Intravenous carbachol stimulated acid secretion in conscious gastric ®stula rats and increased H + K + ATPase mRNA abundance, indicating activation of parietal cells. In these experiments there was no increase in portal venous histamine, or in oxyntic mucosal histidine decarboxylase (HDC) enzyme activity and HDC mRNA abundance. 4 In rat isolated stomachs stimulated with carbachol in the dose range 10 nM ± 1 mM only the 1 mM concentration increased venous histamine signi®cantly. 5 We concluded that the muscarinic agent carbachol stimulates acid secretion and H + K + ATPase mRNA in vivo by a direct eect on the parietal cell, that does not depend on the release of ECL cell histamine.

ECL‐cell histamine mobilization in conscious rats: effects of locally applied regulatory peptides, candidate neurotransmitters and inflammatory mediators

“…Choline esters, such as acetylcholine and carbachol, have been claimed to mobilize histamine from rat and dog stomachs (Stubrin et al ., 1965; Sandvik et al ., 1988c; Gerber & Payne, 1992). On the other hand, there are reports demonstrating a lack of effect of choline esters on ECL‐cell histamine mobilization (Rosengren & Svensson, 1969; Sewing, 1969; Koyama et al ., 1987; Lindström et al ., 1997; Sandvik et al ., 1998; Lindström & Håkanson, 2001). In fact, in the present study, neither of the two choline esters stimulated histamine mobilization in vivo , nor did they inhibit gastrin‐stimulated histamine release.…”

The regulation of gastric acid secretion – clinical perspectives

“…Neither the cholinergic agent carbachol (Sandvik et al . ) nor electrical vagal stimulation (Norlen et al . ) releases histamine directly.…”

Menthol Ameliorates Secretagogue-Induced Gastric Acid Secretion in the Rat

“…In all cases, GAS is significantly reduced, indicating that there may be a significant depression in intracellular free Ca 2+ . It is generally accepted that gastrin acts mainly by releasing histamine from the enterochromaffin-like (ECL) cells in the oxyntic mucosa, so also from actions on parietal cells where they are equally distributed (Prinz, 1993(Prinz, , 1994aSandvik et al, 1998). Furthermore, it has been reported that prostaglandins do exert inhibitory effects on parietal cells (Soll, 1986).…”