Second messengers involved in genetic regulation of the number of calcium channels in bovine adrenal chromaffin cells in culture
| Autor: | C.H. Brennan, J.M. Littleton |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
Dihydropyridines
G protein Inositol Phosphates Gene Expression Biology Pertussis toxin Second Messenger Systems Cellular and Molecular Neuroscience chemistry.chemical_compound Adrenal Glands Phorbol Esters medicine Animals Inositol Virulence Factors Bordetella Inositol phosphate Protein kinase C Cells Cultured Pharmacology chemistry.chemical_classification Dihydropyridine 3-Pyridinecarboxylic acid 1 4-dihydro-2 6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)- Methyl ester Up-Regulation Kinetics medicine.anatomical_structure chemistry Biochemistry Pertussis Toxin Chromaffin cell Second messenger system Chromaffin System Cattle Calcium Channels medicine.drug |
| Zdroj: | Neuropharmacology. 29(7) |
| ISSN: | 0028-3908 |
| Popis: | Bovine adrenal chromaffin cells in culture show an increased formation of [3H]inositol phosphates (after preloading with [3H]inositol) on depolarisation with increased extracellular K+. This increased breakdown of inositol lipid is further increased by the dihydropyridine Ca2+ channel activator BAY K 8644 at nM concentrations, implying that proteins which bind dihydropyridines are involved in this mechanism. Further, pretreatment of adrenal cells with pertussis toxin (100 ng ml−1) prevented the K+-induced breakdown of inositol lipids, arguing the involvement of a pertussis toxin-sensitive G protein in the effect. Chronic exposure of bovine adrenal chromaffin cells to a concentration of ethanol which inhibits K+-induced breakdown of inositol phospholipid, caused a 70–100% increase in the binding of [3H]DHP sites. In these experiments it was found that excess extracellular Ca2+ would considerably reduce this up-regulation, whereas growth of cells in pertussis toxin closely mimicked the up-regulation obtained by growth of cells in ethanol. These experiments suggest that inhibition of membrane Ca2+ flux, through a G protein-associated channel, is closely involved in the ethanol-induced regulation of [3H]dihydropyridine binding sites. The inositol lipid-protein kinase C second messenger system is also implicated in this regulation, by experiments in which inhibitors of protein kinase C (chronic treatment with phorbol myristyl acetate, or with sphingosine) up-regulated binding sites for [3H]dihydropyridine to a similar extent as that seen with growth in ethanol. |
| Databáze: | OpenAIRE |
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