Advertisement

Pflügers Archiv

, Volume 424, Issue 2, pp 195–197 | Cite as

Enhancers of cytosolic cAMP augment depolarization-induced exocytosis from pancreatic B-cells: evidence for effects distal to Ca2+ entry

  • Kevin D. Gillis
  • Stanley Misler
Short Communication Molecular and Cellular Physiology

Summary

We have investigated the effects of cAMP enhancing agents on depolarization-induced membrane capacitance increases (ΔCm in single rat pancreatic B-cells. Concentrations of IBMX, 8-CPT cAMP and forskolin, which enhance cAMP and insulin release, all enhance depolarization-induced ΔCm's seen in response to single voltage-clamp pulses and reduce the depression of ΔCm responses often seen with trains of pulses. These effects often occur in the absence of changes in peak Ca2+ current or the total Ca2+ charge entry during the depolarizing pulse. These data suggest that cAMP modulating maneuvers may directly affect the mechanism of insulin granule mobilization into a readily releasible store or fusion at a discharge site.

Keywords

Depression Human Physiology Forskolin Insulin Release Discharge Site 
These keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. Singer J, Goldberg HM (1970) Evidence for a role of cyclic AMP in neuromuscular transmission. Proc Natl Acad Sci (USA) 64:134–138.Google Scholar
  2. Artalego CR, Ariano MA, Perlman RL, Fox AP (1990) Activation of facilitation calcium channels by D1 dopamine receptors through cAMP/protein kinase A-dependent mechanism. Nature 348:239–242.Google Scholar
  3. Sikdar SK, Zorec R, Mason WT (1990) cAMP directly facilitates Ca2+-induced exocytosis in bovine lactotrophs. FEBS Lett 273:150–154.Google Scholar
  4. Malaisse WJ, Malaisse-Lagae F, Mayhew D (1967) A possible role for the adenylcyclase system in insulin secretion. J Clin Invest 46:1724–1734.Google Scholar
  5. Pipeleers DG, Schmit FC, In'tVeld PA, Maes E, Hooghe-Peters EG, Van de Winkel M, Gepts W (1985) Interplay of nutrients and hormones in the regulation of insulin release. Endocrinology 117:824–833.Google Scholar
  6. Gillis KD, Misler S (1992) Single cell assay of exocytosis from pancreatic islet B-cells. Pflügers Arch (Eur J Physiol) 420:121–123.Google Scholar
  7. Pipeleers D (1987) The biosociology of pancreatic B cells. Diabetologia 30:277–291.Google Scholar
  8. Schmit FC, Pipeleers DG (1985) Regulation of adenosine 3′5′ monophosphate levels in the pancreatic B cell. Endocrinology 117:834–840.Google Scholar
  9. Jones PM, Fyles JM, Howell SL (1986) Regulation of insulin secretion by cAMP in rat islets of Langerhans permeabilized by high voltage discharge. FEBS Lett 205:205–209.Google Scholar
  10. Ämmälä C, Ashcroft FM, Rorsman P (1993) Calcium-independent potentiation of insulin release by cyclic AMP in single B-cells. Nature (in press).Google Scholar
  11. Burgoyne RD (1991) Control of exocytosis in adrenal chromaffin cells. Biochim Biophys Acta 1071:174–202.Google Scholar
  12. Llinas R, Gruner JA, Sugimori M, McGuiness TL, Greengard P (1991) Regulation by synapsin I and Ca2+-calmodulin-dependent protein kinase II of transmitter release in squid giant synapse. J Physiol 436:257–282.Google Scholar

Copyright information

© Springer-Verlag 1993

Authors and Affiliations

  • Kevin D. Gillis
    • 1
  • Stanley Misler
    • 1
  1. 1.Departments of Medicine (Jewish Hospital) and Cell Biology/PhysiologyWashington University Medical CenterSt. LouisUSA

Personalised recommendations