Ion transport in human cecum, transverse colon, and sigmoid colon in vitro

Hubel, Kenneth A.; Renquist, Kathleen E; Shirazi, Siroos S.

doi:10.1016/0016-5085(87)90148-x

Cited by 52 publications

(13 citation statements)

References 13 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Histological (acetylcholinesterase staining; Browning, Hardcastle, Hardcastle & Sanford, 1977) and functional (ACh release; Wu, Kisslinger & Gaginella, 1982) evidence for the presence of cholinergic nerve endings in the colonic mucosa of the rat has been reported. Furthermore, the observation in the present study that the ISC responses to EFS were partly diminished by atropine directly indicates cholinergic innervation adjacent to the epithelium of the rat colon, as demonstrated in the guinea-pig (Kuwahara et al 1987) and human colon (Hubel, Renquist & Shirazi, 1987).…”

Section: Secretory Reflexsupporting

confidence: 71%

Luminal propionate‐induced secretory response in the rat distal colon in vitro.

Yajima

1988

The Journal of Physiology

View full text Add to dashboard Cite

SUMMARY1. The stimulatory action of propionate on colonic electrolyte transport and involvement of the enteric reflex in this was studied in vitro using an Ussing chamber in the rat. The short-circuit current (I.,) and bidirectional fluxes of Na+ and Cl-were measured. Mucosa-submucosa preparations, containing the submucosal nerve, from the distal colon were used in most cases.2. Mucosal application of propionate caused transient increases in the transmural potential difference, with the mucosal side negative, ISc and conductance. Serosal application of the acid had no effect.3. Adaptation of the ISC response occurred when the acid was applied to the bathing solution cumulatively without washing out the first dose. If tissues were washed and held more than 20 min before the next application, the response was almost completely restored.4. The increase in IS. in response to propionate was concentration dependent, with a 50% effective concentration of approximately 7 x 10-5 M.5. Two other short-chain fatty acids (SCFAs), n-butyrate and n-valerate, but not acetate, increased ISC when added to the mucosal bathing solution.6. Bumetanide (3 x 10-5 M) and the serosal chloride-free condition, but not amiloride (10-M), inhibited the responses of ISC to propionate. Propionatestimulated Cl-secretion resulted mainly from an increase in unidirectional serosalto-mucosal C1-movement. Propionate did not affect the Na+ flux.7. Tetrodotoxin (10-7 M), somatostatin (10-7 M) and hexamethonium (10-4 M) inhibited the propionate-evoked increase in ISC by 40, 70 and 30°%, respectively.8. Atropine (10-5 M) also inhibited the I,,-increase response to propionate more than 90 %.9. Pre-treatment (2 min) of the mucosal surface with procaine (5 x 10-M)inhibited the propionate-evoked increase in IS. by 90°%.10. The results suggest that luminal propionate transiently stimulated the colonic chloride secretory response that is not due to direct action on colonocytes, but due in large part to release of acetylcholine at neuro-colonocyte junctions, probably via an enteric reflex involving a mucosal sensory mechanism, cholinergic motor nerves and submucosal ganglia.

show abstract

Section: Secretory Reflexsupporting

confidence: 71%

Luminal propionate‐induced secretory response in the rat distal colon in vitro.

Yajima

1988

The Journal of Physiology

View full text Add to dashboard Cite

show abstract

“…Newer understanding of the role of corticosteroids in the regulation of colonic electrolyte transport has raised the possibility that the antidiarrheal action of these steroids in inflammatory bowel disease may also be related to their proabsorptive effect on electrolyte movement (1,29). The results of this present study together with the recent demonstration that sodium and chloride are actively absorbed throughout the normal human colon predominantly by electroneutral transport mechanisms (30)(31)(32) may have important therapeutic implications for inflammatory bowel disease. An ultrapure glucocorticoid receptor-specific agonist such as RU 28362 may provide greater efficacy with fewer side effects than the presently used "glucocorticoids" which manifest significant mineralocorticoid agonist activity.…”

Section: Discussionmentioning

confidence: 53%

Regulation of active sodium and potassium transport in the distal colon of the rat. Role of the aldosterone and glucocorticoid receptors.

Turnamian¹,

Binder²

1989

J. Clin. Invest.

View full text Add to dashboard Cite

To determine whether mineralocorticosteroids and glucocorticosteroids have specific effects on colonic electrolyte transport, we compared the effect of aldosterone and RU 28362, a glucocorticoid receptor-specific agonist that does not bind to the aldosterone receptor, on unidirectional Na, Cl, and K fluxes across isolated mucosa of the rat distal colon. Continuous infusion of aldosterone for 7 d produced changes in four specific transport processes: induction of both active electrogenic, amiloride-sensitive sodium absorption and active electrogenic potassium secretion, enhancement of active electroneutral potassium absorption, and inhibition of electroneutral Na-Cl absorption, the predominant transport process in this epithelium. In contrast, continuous infusion of RU 28362 for 1-11 d produced a sustained increase in electroneutral Na-Cl absorption. This glucocorticoid receptor-specific agonist did not induce electrogenic sodium absorption nor affect either potassium absorption or secretion. These studies demonstrate that aldosterone (i.e., mineralocorticoid) and glucocorticoid receptors modulate separate and specific changes in active sodium and potassium transport. These results suggest that other glucocorticoids (e.g., dexamethasone, methylprednisolone) are not glucocorticoid receptor-specific and that their effects on electrogenic sodium absorption and potassium transport most likely represent the binding of these agonists to the aldosterone receptor.

show abstract

“…In a flux chamber study of ion transport in the human colon, sodium was absorbed throughout entire colon, but maximally in the transverse colon (Hunbel et al 1987). In addition, not only mineralocorticoids but also glucocorticoids are considered to promote active transport in the colon (Halevy et al 1988).…”

Section: Discussionmentioning

confidence: 99%