Control of K+ conductance by cholecystokinin and Ca2+ in single pancreatic acinar cells studied by the patch-clamp technique |
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Authors: | Yoshio Maruyama Ole H Petersen |
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Institution: | (1) MRC Secretory Control Research Group, The Physiological Laboratory, University of Liverpool, L69 3BX Liverpool, England |
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Abstract: | Summary The effect of cholecystokinin (CCK) and internal Ca2+ on outward K+ current in isolated pig pancreatic acinar cells has been investigated using the patch-clamp method for whole-cell current recording under voltage-clamp conditions. CCK (2 × 10–10
M) applied to the bath evoked a marked increase in the outward K+ current associated with depolarizing voltage steps, and this effect was fully reversible and acutely dependent on the presence of external Ca2+. When strongly buffered Ca2+-EGTA solutions were used inside the cells CCK failed to evoke an effect. Increasing the internal Ca2+ concentration (Ca2+]
i
) from 5 × 10–10
M to 10–7 and 5 × 10–7
M mimicked the effect of CCK. It would appear therefore that CCK controls K+ conductance in the acinar cells via changes in the internal free ionized Ca2+ concentration. |
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Keywords: | pancreatic acinar cells patch clamp whole cell recording single channel recording K+ channel Ca2– control cholecystokinin |
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