Gap junctional conductance tunes phase difference of cholecystokinin evoked calcium oscillations in pairs of pancreatic acinar cells.
Using the double whole-cell recording technique we measured the gap junctional conductance (gj), while simultaneously monitoring the cytoplasmic free calcium concentration ([Ca2+i]) in isolated acinar cell pairs from the pancreas of mouse. Physiological concentrations of the secretagogue cholecystokinin-octapeptide (CCK-OP) elicited [Ca2+i] oscillations and after a delay in the minute range reduced gj. The results provide the first evidence suggesting that gj regulates the phase difference (delta phi) of [Ca2+i] oscillations between neighbouring cells not in an all or none process, but with decreasing absolute value of gj delta phi monotonically increases. CCK-OP induced electrical uncoupling as well as the corresponding increase of delta phi could be blocked completely by the protein kinase C inhibitor polymyxin B. The data support the hypothesis that Ca2+ flow through gap junctions synchronizes [Ca2+i] oscillations between jap junctional coupled cells.
Ngezahayo
A
A
University of Konstanz, Faculty of Biology, Germany.
Kolb
H A
HA
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002766:Cholecystokinin / Q000494:pharmacology*; D007365:Intercellular Junctions / Q000187:drug effects / Q000502:physiology*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D051379:Mice; D010179:Pancreas / Q000166:cytology / Q000378:metabolism / Q000502:physiology*
D002766:Cholecystokinin; D002118:Calcium