An intermediate-conductance Ca²⁺-activated K⁺ channel is important for secretion in pancreatic duct cells

TY - JOUR

T1 - An intermediate-conductance Ca2+-activated K+ channel is important for secretion in pancreatic duct cells

AU - Hayashi, Mikio

AU - Wang, Jing

AU - Hede, Susanne Edeling

AU - Novak, Ivana

PY - 2012/7/15

Y1 - 2012/7/15

N2 - Potassium channels play a vital role in maintaining the membrane potential and the driving force for anion secretion in epithelia. In pancreatic ducts, which secrete bicarbonate-rich fluid, the identity of K(+) channels has not been extensively investigated. In this study, we investigated the molecular basis of functional K(+) channels in rodent and human pancreatic ducts (Capan-1, PANC-1, and CFPAC-1) using molecular and electrophysiological techniques. RT-PCR analysis revealed mRNAs for KCNQ1, KCNH2, KCNH5, KCNT1, and KCNT2, as well as KCNN4 coding for the following channels: KVLQT1; HERG; EAG2; Slack; Slick; and an intermediate-conductance Ca(2+)-activated K(+) (IK) channel (K(Ca)3.1). The following functional studies were focused on the IK channel. 5,6-Dichloro-1-ethyl-1,3-dihydro-2H-benzimidazole-2-one (DC-EBIO), an activator of IK channel, increased equivalent short-circuit current (I(sc)) in Capan-1 monolayer, consistent with a secretory response. Clotrimazole, a blocker of IK channel, inhibited I(sc). IK channel blockers depolarized the membrane potential of cells in microperfused ducts dissected from rodent pancreas. Cell-attached patch-clamp single-channel recordings revealed IK channels with an average conductance of 80 pS in freshly isolated rodent duct cells. These results indicated that the IK channels may, at least in part, be involved in setting the resting membrane potential. Furthermore, the IK channels are involved in anion and potassium transport in stimulated pancreatic ducts.

AB - Potassium channels play a vital role in maintaining the membrane potential and the driving force for anion secretion in epithelia. In pancreatic ducts, which secrete bicarbonate-rich fluid, the identity of K(+) channels has not been extensively investigated. In this study, we investigated the molecular basis of functional K(+) channels in rodent and human pancreatic ducts (Capan-1, PANC-1, and CFPAC-1) using molecular and electrophysiological techniques. RT-PCR analysis revealed mRNAs for KCNQ1, KCNH2, KCNH5, KCNT1, and KCNT2, as well as KCNN4 coding for the following channels: KVLQT1; HERG; EAG2; Slack; Slick; and an intermediate-conductance Ca(2+)-activated K(+) (IK) channel (K(Ca)3.1). The following functional studies were focused on the IK channel. 5,6-Dichloro-1-ethyl-1,3-dihydro-2H-benzimidazole-2-one (DC-EBIO), an activator of IK channel, increased equivalent short-circuit current (I(sc)) in Capan-1 monolayer, consistent with a secretory response. Clotrimazole, a blocker of IK channel, inhibited I(sc). IK channel blockers depolarized the membrane potential of cells in microperfused ducts dissected from rodent pancreas. Cell-attached patch-clamp single-channel recordings revealed IK channels with an average conductance of 80 pS in freshly isolated rodent duct cells. These results indicated that the IK channels may, at least in part, be involved in setting the resting membrane potential. Furthermore, the IK channels are involved in anion and potassium transport in stimulated pancreatic ducts.

KW - Animals

KW - Cells, Cultured

KW - Female

KW - Humans

KW - Intermediate-Conductance Calcium-Activated Potassium Channels

KW - Male

KW - Membrane Potentials

KW - Mice

KW - Mice, Inbred BALB C

KW - Mice, Inbred C57BL

KW - Pancreatic Ducts

KW - Potassium Channel Blockers

KW - Rats

KW - Rats, Wistar

U2 - 10.1152/ajpcell.00089.2012

DO - 10.1152/ajpcell.00089.2012

M3 - Journal article

C2 - 22555847

SN - 0363-6143

VL - 303

SP - C151-C159

JO - American Journal of Physiology: Cell Physiology

JF - American Journal of Physiology: Cell Physiology

IS - 2

ER -