Control of K+ conductance by cholecystokinin and Ca2+ in single pancreatic acinar cells studied by the patch-clamp technique.
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 X 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 X 10(-8) M to 10(-7) and 5 X 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.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002766:Cholecystokinin / Q000494:pharmacology*; D004553:Electric Conductivity; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects; D010179:Pancreas / Q000166:cytology / Q000502:physiology*; D011188:Potassium / Q000378:metabolism*; D013552:Swine
D007473:Ion Channels; D002766:Cholecystokinin; D011188:Potassium; D002118:Calcium