In vitro behavior of human intestinal mucosa. The influence of acetyl choline on ion transport.

Abstract

A B S T R A C T The possibility that the autonomic nervous system may influence the function of intestinal mucosa was investigated by assessing the effect of acetyl choline on ion transport in human intestine. Isolated pieces of stripped ileal mucosa were mounted in Perspex flux-chambers and bathed in isotonic glucose Ringer's solution. Acetyl choline caused a rise in mean potential difference (8.8-12.3 mV, P < 0.002) and short circuit current (287.7-417.2 A'A -cm-2, P < 0.01) (n = 12), observable at a concentration of 0.01 mM and maximal at 0.1 mM. This effect was enhanced by neostigmine and blocked by atropine. Isotopic flux determinations revealed a change from a small mean net Cl absorption (+ 0.58) to a net Cl secretion (-4.3 Aeq-cmf'-h P < 0.001) due predominantly to an increase in the serosal to mucosal unidirectional flux of Cl (10.63-14.35 ueq. cm . h-' P < 0.05) and a smaller reduction in the mucosal to serosal flux (11.22 to 10.02 /Aeq cm-' h' P < 0.05). Unidirectional and net Na transport was unaffected. A similar electrical and ion transport response was observed in a single study of two pieces of jejunal mucosa. In the absence of glucose net chloride secretion was produced and again an insignificant effect on net sodium transport was noted. Acetyl choline did not provoke a sustained effect on mucosal cyclic adenine nucleotide levels although a short-lived cyclic adenine nucleotide response was seen in some tissues 20-30 s after drug addition.These studies demonstrate that acetyl choline does influence human intestinal ion transport by stimulating chloride secretion and suggest a possible mechanism by A preliminary report of this work was presented at the British Society of Gastroenterology, Southampton, April 1975 and at the European Society for Clinical Investigation, Rotterdam, April, 1975. Received for publication 20 August 1975 and in revised formn 13 May 1976. which the parasympathetic nervous system could be concerned in the control of ion transport. INTRODUCTION It has long been thought that the autonomic nervous system may influence intestinal absorption and secretion. Sympathetic denervation in the dog and the cat caused an intestinal secretion which was blocked by atropine(1) and the spontaneous secretion of Thirty-Vella loops of dog ileum was similarly prevented by atropine (2).More recently Caren and co-workers (3) showed that the secretion provoked by tactile stimulation in such isolated loops was inhibited by atropine and hexamethonium. Pilocarpine (4) and eserine (5) caused intestinal secretion and bethanechol, a cholinergic agent, was shown to induce a net secretion of chloride in dog jejunum (6). In view of these suggestive pieces of evidence the present investigations were undertaken to examine in more detail the influence of acetyl choline on human intestinal ion transport. The results indicate that acetyl choline does influence ion transport in vitro and suggest a possible mechanism by which the parasympathetic nervous system could be involved in the control of intestina...

Choline Acetyltransferase (ChAT) Immunoreactivity in Paraffin Sections of Normal and Diseased Intestines

“…In human tissues we often observed a few linear bands of staining in the mucosa, but in view of the strong vascular staining seen elsewhere, we interpreted this as endothelial immunoreactivity. Although functional, pharmacological, and physiological evidence suggests that a population of cholinergic nerves innervate the mucosa (Isaacs et al 1976;Cooke 1984; Figure 4 ChAT IR in normal human colon. (A) Strong staining of the epithelial brush border (asterisk) with much weaker staining of epithelial cell cytoplasm.…”

“…Bars ϭ 100 m. Chandan et al 1991a,b;Javed and Cooke 1992), we are unaware of any reports providing conclusive histological evidence. Reports using AChE histochemistry on normal mucosa either have dubious specificity (Isaacs et al 1976) or report few or no cholinergic nerve fibers (Lake et al 1978). Studies with ChAT immunohistochemistry on whole mounts have traced ChAT IR nerve processes to the mucosa but have not demonstrated ChAT IR nerve fibers in this compartment (Furness et al 1985).…”

“…The pattern of epithelial ChAT IR seen in both human and rat may be connected to the role of acetylcholine in mucosal ion transport (Isaacs et al 1976;Cooke 1984;Chandan et al 1991a,b;Javed and Cooke 1992). In this context, it is interesting to note that acetylcholinesterase activity is present in some epithelia, including large bowel (Sine et al 1991), epidermis (Grando et al 1993), and amniotic epithelial cells (Sakuragawa et al 1997), and that ChAT is also capable of hydrolyzing acetylcholine (Molenaar 1990).…”

“…Cholinergic nerves mediate increased gut activity, such as contraction (Debas and Mulvihill 1991), and are associated with mucosal ion transport (Isaacs et al 1976;Cooke 1984;Chandan et al 1991a,b;Javed and Cooke 1992). At present, acetylcholinesterase (AChE) activity is the usual marker of cholinergic nerves and has become a widely accepted technique for diagnosis of Hirschsprung's disease (Lake et al 1978), in which extrinsic nerve fibers penetrate the full thickness of the aganglionic segment of colon (Mackenzie and Dixon 1987;Tam and Boyd 1990).…”

The effects of Clostridium difficile crude toxins and purified toxin A on stripped rabbit ileal mucosa in Ussing chambers

“…The activity for 22Na multiplied by a factor for the relative efficiency of the two counters for 22Na was subtracted from the total radioactivity to yield the counts due to 36Cl. Unidirectional and net ion fluxes were calculated by the method of Isaacs et al (1976).…”