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Pflügers Archiv

, Volume 428, Issue 1, pp 69–75 | Cite as

Ca2+-dependent unidirectional vesicular release detected with a carbon-fibre electrode in rat pancreatic acinar cell triplets

  • Yukinari Tomita
  • Gen Inooka
  • Hitoshi Shimada
  • Yoshio Maruyama
Transport Processes, Metabolism and Endocrinology; Kidney, Gastrointestinal Tract, and Exocrine Glands

Abstract

An amperometric constant-voltage method for detection of serotonin oxidation currents was applied to pancreatic acinar cell triplets to determine the site of release of granular content following an increase in [Ca2+]i. The carbon fibre electrode, fabricated to be compatible with a conventional patch-clamp amplifier, was voltage-clamped at 600 mV exceeding the serotonin oxidation voltage, 300 mV. The electrode was placed on the different regions of cell surface of acinar cell triplets loaded with exogenous serotonin. Transient oxidation currents were detected only when the electrode was placed on the acinar lumen after stimulation with a Ca2+ ionophore, A23187, but never observed on the basal or lateral cell surface, or paracellular clefts. No such current responses were observed in the acinar cells without serotonin loading. The results indicate that the A23187-induced sustained increase in [Ca2+]i discharges serotonin specifically into the lumen, and provides direct evidence for the presence of Ca2+-dependent unidirectional release of granular contents in pancreatic acinar cells.

Key words

Polarized secretion Pancreatic acinar cells Oxidation currents Carbon fibre electrode Ca2+-dependent exocytosis 

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Copyright information

© Springer-Verlag 1994

Authors and Affiliations

  • Yukinari Tomita
    • 1
  • Gen Inooka
    • 1
  • Hitoshi Shimada
    • 1
  • Yoshio Maruyama
    • 1
  1. 1.Department of PhysiologyJichi Medical SchoolTochigiJapan

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