Distinct Characteristics of Receptor-Operated Ca2+ Influx and Refilling in Pancreatic Acinar Cells

Author: Tsunoda Y.   Tashiro Y.  

Publisher: Elsevier

ISSN: 0006-291X

Source: Biochemical and Biophysical Research Communications, Vol.256, Iss.3, 1999-03, pp. : 579-583

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Abstract

Ca2+ influx from the extracellular space in nonexcitable cells occurs via receptor-operated and refilling processes. However, they showed different characteristics with respect to the Mn2+ permeability, depletion of intracellular Ca2+ stores, and sensitivity to the K+ ionophore valinomycin in rat pancreatic acinar cells. While Mn2+ did not enter into the cells during the refilling phase, the opposite was true in receptor-operated Ca2+ influx (ROCI) evoked by carbachol (CCh). ROCI occurred in the absence of intracellular Ca2+ release from the stores. Valinomycin abolished the second response of Ca2+ elicited by CCh, whereas it had no effect on ROCI. These observations suggest that receptor-operated Ca2+ channels (ROCCs) and refilling channels may be different in rat pancreatic acinar cells.

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