Cytosolic Ca2+ gradients triggering unidirectional fluid secretion from exocrine pancreas

Nature. 1990 Dec 20-27;348(6303):735-8. doi: 10.1038/348735a0.

Abstract

Exocrine gland cells secrete Cl(-)-rich fluid when stimulated by neurotransmitters or hormones. This is generally ascribed to a rise in cytosolic Ca2+ concentration ([Ca2+]i), which leads to activation of Ca2(+)-dependent ion channels. A precise understanding of Cl- secretion from these cells has been hampered by a lack of knowledge about the spatial distribution of the Ca2+ signal and of the Ca2(+)-dependent ion channels in the secreting epithelial cells. We have now used the whole-cell patch-clamp method and digital imaging of [Ca2+]i to examine the response of rat pancreatic acinar cells to acetylcholine. We found a polarization of [Ca2+]i elevation and ion channel activation, and suggest that this comprises a novel 'push-pull' mechanism for unidirectional Cl- secretion. This mechanism would represent a role for cytosolic Ca2+ gradients in cellular function. The cytosolic [Ca2+]i gradients and oscillations of many other cells could have similar roles.

Publication types

  • Research Support, Non-U.S. Gov't
  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Acetylcholine / pharmacology
  • Animals
  • Calcium / metabolism*
  • Chloride Channels
  • Chlorides / metabolism*
  • Cytosol / metabolism*
  • Electric Conductivity
  • Fluorescent Dyes
  • Fura-2
  • Ion Channels / physiology
  • Membrane Potentials
  • Membrane Proteins / physiology
  • Pancreas / drug effects
  • Pancreas / metabolism*
  • Pancreatic Juice / metabolism
  • Potassium / pharmacology
  • Rats
  • Rats, Inbred Strains
  • Signal Transduction / physiology

Substances

  • Chloride Channels
  • Chlorides
  • Fluorescent Dyes
  • Ion Channels
  • Membrane Proteins
  • Acetylcholine
  • Potassium
  • Calcium
  • Fura-2