Activation of the inositol trisphosphate second messenger system by cAMP in a mouse fibroblast cell line |
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Authors: | Valerie J Horn Paul A Sheehy Miriam B Goodman Indu S Ambudkar |
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Institution: | (1) Clinical Investigations and Patient Care Branch, NIDR, National Institutes of Health, 20892 Bethesda, MD, USA;(2) Laboratory of Neurophysiology, NINCDS, National Institutes of Health, 20892 Bethesda, MD, USA;(3) Building 10, Room lA05, NIDR, NIH, 20892 Bethesda, MD, USA |
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Abstract: | Intracellular Ca2+ mobilization events were assessed in mouse L cells, which contain native prostaglandin E1 receptors and transfected human 2 adrenergic receptors. Both Fura2 (single cell measurements) and Quin 2, (cuvette assays) were used to determine Ca2+]i levels. Our results demonstrate that in the transfected cells there is a dose-dependent increase in Ca2+]i in response to isoproterenol (0.1 nM–100 nM), which is inhibited by the -adrenergic antagonist, propranolol, and is a result of intracellular Ca2+ release. Ca2+]1 in these cells was also increased by prostaglandin E1, 8 bromo cyclic AMP, and aluminum fluoride. Both 8 bromo cAMP and isoproterenol induced a rapid increase in the levels of IP1, IP2, and IP3. The data presented demonstrate that the elevation of intracellular cyclic AMP induces an increase in IP3 production which leads to an elevation in Ca2+];. We propose that this cyclic AMP dependent activation of the IP3 generating system occurs at a post-receptor site.Abbreviations cAMP
Adenosine Cyclic 3-5-Monophosphate
- Ca2+]i
intracellular Ca2+]i
- 8 Br cAMP
8 Bromo Adenosine Cyclic 3-5-Monophosphate
- DAG
Diacylglycerol
- EGTA]
Ethylene Bis (oxyethylenenitrilo)] Tetracetic acid
- BSA
Bovine Serum Albumin
- HBSS-H
Hanks' Balanced Salt Solution buffered with HEPES to pH 7.4
- HEPES
4-(2-Hydroxyethyl)-1-piperazineethanesulfonic acid
- PIP2
Phosphatidylinositol 4,5-bisphosphate
- IP2
Inositol 4 Phosphate
- IP2
Inositol 4,5 Bisphosphate
- IP3
Inositol Trisphosphate
- PGE1
Prostaglandin E1
- PBS
Phosphate Buffered Saline Solution |
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Keywords: | cAMP inositol trisphosphate calcium mobilization fibroblasts receptor cross-talk |
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