Triggered exocytosis may not incorporate functional Cl(-)-channels into the luminal membrane in pancreatic acinar cells.
Pancreatic acinar cells secrete Cl- rich fluid and release digestive enzymes into the lumen. Ca(2+)-dependent Cl(-)-channels in the luminal membrane participate such unidirectional Cl- secretion after stimulation of basolateral surface receptors. Simultaneous recordings of increases in membrane capacitance (an estimate of granular fusion or of increase in membrane surface area) and conductance (reflecting activities of Cl- and Na/K nonselective cation channels) demonstrate that an increase in membrane capacitance (delta C) lags behind that of membrane conductance (delta G) after an increase in [Ca2+]i by muscarinic receptor stimulation and/or using A23187. The take-off of delta C never accompanies any notches or humps in the paired delta G-trace. The results suggest that granular fusion does not incorporate functional channels into the luminal membrane during the stimulation of secretagogues.
Maruyama
Y
Y
Department of Physiology, Jichi Medical School, Tochigi, Japan.
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002462:Cell Membrane; D018118:Chloride Channels / Q000502:physiology*; D005089:Exocytosis; D010179:Pancreas / Q000502:physiology*; D051381:Rats; D013997:Time Factors
D018118:Chloride Channels; D002118:Calcium