Down-Modulation of Ca2+ Channels by Endogenously Released ATP and Opioids: from the Isolated Chromaffin Cell to the Slice of Adrenal Medullae
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Modifications in Ca2+ influx may lead to profound changes in the cell activity associated with Ca2+-dependent processes, from muscle contraction and neurotransmitter release to calcium-mediated cell death. Therefore, calcium entry into the cell requires fine regulation. In this context, understanding of the modulation of voltage-dependent Ca2+ channels seems to be critical. The modulatory process results in the enhancement or decrement of calcium influx that may regulate the local and global cytosolic Ca2+ concentrations. Here, we summarize the well-established data on this matter described in isolated chromaffin cells by our laboratory and others, and the new results we have obtained in a more physiological preparation: freshly isolated slices of mouse adrenal medullae.
KeywordsMouse adrenal slices Ca2+ channels Chromaffin cells Autocrine modulation Paracrine modulation ATP Methionine-enkephalin
The authors are indebted to Nicolás Jiménez for technical support and Claudia V. Rivera, head of the IFC Animal Facility for continuous advice. This work was supported by Instituto de Salud Carlos III (grant PI080227 to J. M. H.-G.), and DGAPA-UNAM (grant IN227910 to A. H.-C.), and CONACyT (grants 42662, 79763, and 102085 to A. H.-C.). P. S. receives a Ph.D. fellowship from CONACyT. A. H. a former postdoctoral fellow from CTIC-DGAPA, UNAM and presently postdoctoral fellow from CONACyT. E. A. receives a Ph.D fellowship from Fundación Teófilo Hernando. We also acknowledge financial support from the cooperation agreement between the National Autonomous University of México (UNAM) and the Autonomous University of Madrid (UAM), and CEAL-UAM-Banco de Santander.
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