The ryanodine receptor mediates early zymogen activation in pancreatitis

AUTOR(ES)
FONTE

National Academy of Sciences

RESUMO

Acute pancreatitis is characterized by the pathologic activation of zymogens within pancreatic acinar cells. The process requires a rise in cytosolic Ca2+ from undefined intracellular stores. We hypothesized that zymogen activation is mediated by ryanodine receptor (RYR)-regulated Ca2+ release, because early zymogen activation takes place in a supranuclear compartment that overlaps in distribution with the RYR. Ca2+ signals in the basolateral, but not apical, region of acinar cells observed during supraphysiologic agonist stimulation were dependent on RYR Ca2+ release. Inhibition of RYR or depletion of RYR-sensitive Ca2+ pools each reduced pathologic zymogen activation in isolated acinar cells, but neither treatment affected amylase secretion. Inhibition of RYR also inhibited zymogen activation in vivo. We propose that Ca2+ release from the RYR mediates zymogen activation but not enzyme secretion. The findings imply a role for the RYR in acute pancreatitis.

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