Effect of Bicarbonate on Potassium Conductance of Isolated Perfused Rat Pancreatic Ducts

Overview

Journal Pflugers Arch

Specialty Physiology

Date 1991 Aug 1

PMID 1945765

Citations 17

Authors

I Novak

R Greger

Affiliations

Soon will be listed here.

Abstract

The aim of this study was to investigate the role of the K+ conductance in unstimulated and stimulated pancreatic ducts and to see how it is affected by provision of exogenous HCO3-/CO2. For this purpose we have applied electrophysiological techniques to perfused pancreatic ducts, which were dissected from rat pancreas. The basolateral membrane potential PDbl of unstimulated duct cells was between -60 mV and -70 mV, and the cells had a relatively large K+ conductance in the basolateral membrane as demonstrated by (a) 20-22 mV depolarization of PDbl in response to increase in bath K+ concentration from 5 mmol/l to 20 mmol/l and (b) the effect of a K+ channel blocker, Ba2+ (5 mmol/l), which depolarized PDbl by 30-40 mV. These effects on unstimulated ducts were relatively independent of bath HCO3-/CO2. The luminal membrane seemed to have no significant K+ conductance. Upon stimulation with secretin or dibutyryl cyclic AMP, PDbl depolarized to about -35 mV in the presence of HCO3-/CO2. Notably, the K+ conductance in the stimulated ducts was now only apparent in the presence of exogenous HCO3-/CO2 in the bath solutions. Upon addition of Ba2+, PDbl depolarized by 13 +/- 1 mV (n = 7), the fractional resistance of the basolateral membrane, FRbl increased from 0.66 to 0.78 (n = 6), the specific transepithelial resistance, Rte, increased from 52 +/- 13 omega cm2 to 59 +/- 15 omega cm2 (n = 11), and the whole-cell input resistance, Rc, measured with double-barrelled electrodes, increased from 20 M omega to 26 M omega (n = 3).(ABSTRACT TRUNCATED AT 250 WORDS)

Citing Articles

Synergistic effects of agonists and two-pore-domain potassium channels on secretory responses of human pancreatic duct cells Capan-1.

Sorensen C, Trauzold A, Christensen N, Tawfik D, Szczepanowski M, Novak I Pflugers Arch. 2022; 475(3):361-379.

PMID: 36534232 PMC: 9908661. DOI: 10.1007/s00424-022-02782-9.

Proton Pump Inhibitors Reduce Pancreatic Adenocarcinoma Progression by Selectively Targeting H, K-ATPases in Pancreatic Cancer and Stellate Cells.

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PMID: 32164284 PMC: 7139746. DOI: 10.3390/cancers12030640.

Bicarbonate-rich fluid secretion predicted by a computational model of guinea-pig pancreatic duct epithelium.

Yamaguchi M, Steward M, Smallbone K, Sohma Y, Yamamoto A, Ko S J Physiol. 2016; 595(6):1947-1972.

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Proton Pump Inhibitors Inhibit Pancreatic Secretion: Role of Gastric and Non-Gastric H+/K+-ATPases.

Wang J, Barbuskaite D, Tozzi M, Giannuzzo A, Sorensen C, Novak I PLoS One. 2015; 10(5):e0126432.

PMID: 25993003 PMC: 4436373. DOI: 10.1371/journal.pone.0126432.

Potassium channels in pancreatic duct epithelial cells: their role, function and pathophysiological relevance.

Venglovecz V, Rakonczay Jr Z, Gray M, Hegyi P Pflugers Arch. 2014; 467(4):625-40.

PMID: 25074489 DOI: 10.1007/s00424-014-1585-0.

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