Does the hydrolysis of inositol phospholipids lead to the opening of voltage operated Ca2+ channels in guinea-pig ileum? Studies with fluoride ions and caffeine

Stephen P. Watson, Alison F. Stanley, Toshiyuki Sasaguri

Research output: Contribution to journalArticlepeer-review

12 Citations (Scopus)

Abstract

Fluoride ions (1 - 30 mM) stimulate phosphoinositide hydrolysis in guinea-pig ileum longitudinal smooth muscle slices, and this is not inhibited in the presence of indomethacin or nifedipine. This action is associated with a slow contractile response which peaks after approximately five minutes and then declines towards baseline; at this time the contractile response to a maximally effecive concentration of carbachol is also inhibited. Fluoride-induced contractions are inhibited completely in the presence of nifedipine. Similarly, contractions induced by caffeine, which releases Ca2+ from intracellular stores, are also inhibited by nifedipine. These data are consistent with a model in which the activation of a G-protein by F- ions leads to the following sequential events: activation of phospholipase C, release of intracellular Ca2+ opening of voltage operated (i.e. dihydropyridine sensitive) Ca2+ channels and contraction. The transient nature of the fluoride contraction and the inhibition of the carbachol contraction may be due to a slow elevation of cAMP levels induced by F-.

Original languageEnglish
Pages (from-to)14-20
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume153
Issue number1
DOIs
Publication statusPublished - May 31 1988
Externally publishedYes

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Biochemistry
  • Molecular Biology
  • Cell Biology

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