Pattern of Ca2+ increase determines the type of secretory mechanism activated in dog pancreatic duct epithelial cells.

摘要: Intracellular calcium concentration ([Ca2+]i) is a key factor controlling secretion from various cell types. We investigated how different patterns of [Ca2+]i signals evoke salt via ion transport mechanisms and mucin exocytosis in dog pancreatic duct epithelial cells (PDEC). Activation P2Y2 receptors by UTP generated two change: 2–10 μm induced oscillations, whereas 100 sustained increase, both the micromolar range. As monitored carbon-fibre amperometry, increase stimulated larger than despite their similar amplitude. In contrast, patch-clamp recordings revealed that oscillations synchronously activated K+ current as efficiently increase. This was mediated intermediate-conductance Ca2+-activated channels (32 pS at −100 mV) which were sensitive to charybdotoxin resistant TEA. these Ca2+-dependent hyperpolarized plasma membrane resting potential −40 mV −90 mV, perforated whole-cell configuration, turn enhancing Na+-independent, Cl−-dependent DIDS-sensitive HCO3− secretion, through changes intracellular pH. PDEC therefore encode concentrations purinergic agonists changes, differentially stimulate channels, Cl−–HCO3− exchanger, exocytosis. Thus, addition amplitude, temporal pattern increases an important mechanism for transducing extracellular stimuli into physiological effects.