pH and smooth muscle: regulation and functional effects

Wray, Susan; Bullock, Anthony J.; Buttell, N.; Duquette, Robert A.

doi:10.1017/cbo9780511542640.014

Cited by 1 publication

(1 citation statement)

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“…Thus our findings are not dependent upon the method used to induce the pH change. Studies in other cell types have indicated that three sarcolemmal ion transporters may mediate acid-equivalent efflux: Na + /H + exchange, Na + -HCO 3 -co-transport and Na-dependent Cl -/HCO 3 -exchange [39]. As there was little previous data for gastric myocytes, we concentrated our investigation on non-HCO 3 --based mechanisms.…”

Section: Regulationmentioning

confidence: 99%

pH regulation and buffering power in gastric smooth muscle

Duquette

Wray

2001

Pflügers Arch - Eur J Physiol

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Intracellular pH can have profound effects on tissue function, but little is known about how pH is regulated, buffered or affects the function of gastric smooth muscle. As the pH of gastric myocytes may alter with pathophysiological disturbance of the gastric lining, or reduction in blood flow to the stomach, these parameters were investigated. Intracellular pH was measured in strips of corpus from rats and guinea-pigs and pH perturbed by the addition of Na butyrate. pH regulation was investigated using pharmacological inhibitors and ionic substitutions. Resting pH was found to be around 7.0, and buffering power relatively high, compared to other muscles in both species. In the guinea-pig amiloride, EIPA and HOE694 prevented pH regulation from an acid load, but amiloride- and EIPA-insensitive pH-regulating mechanisms were found in the rat. The pH-regulatory mechanism present in the rat was also insensitive to DIDS, SITS and removal of external Cl-, but inhibited by Na+ substitution and HOE694. Acidification reduced gastric tone in both species. We conclude that pH alteration will significantly affect gastric contractility, despite a high capacity of the tissue to buffer and regulate pH change. The sensitivity to NHE inhibitors differs between rat and guinea-pig, suggesting that Na+/H+ exchanger isoform expression differs between gastric tissue.

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Section: Regulationmentioning

confidence: 99%