Early effects of PRL on ion conductances in CHO cells expressing PRL receptor
| Autor: | Natalia Prevarskaya, C. Bignon, Bernard Dufy, R. Skryma, J Djiane, N Daniel, Pierre Vacher |
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| Přispěvatelé: | ProdInra, Migration, Unité de biologie cellulaire et moléculaire, Institut National de la Recherche Agronomique (INRA) |
| Rok vydání: | 1994 |
| Předmět: |
endocrine system
DNA Complementary Charybdotoxin Receptors Prolactin Physiology [SDV]Life Sciences [q-bio] Scorpion Venoms CHO Cells Tetrodotoxin Biology Transfection MICROFLUOROMETRIE Membrane Potentials 03 medical and health sciences 0302 clinical medicine Cricetinae Complementary DNA Animals Fluorometry Receptor ComputingMilieux_MISCELLANEOUS 030304 developmental biology 0303 health sciences Cell-Free System Chinese hamster ovary cell Electric Conductivity Intracellular Membranes Cell Biology Molecular biology Prolactin [SDV] Life Sciences [q-bio] Potassium Calcium hormones hormone substitutes and hormone antagonists 030217 neurology & neurosurgery |
| Zdroj: | American Journal of Physiology-Cell Physiology American Journal of Physiology-Cell Physiology, American Physiological Society, 1994, 267, pp.C554-C562 |
| ISSN: | 1522-1563 0363-6143 |
| DOI: | 10.1152/ajpcell.1994.267.2.c554 |
| Popis: | Chinese hamster ovary (CHO-K1) cells were stably transfected with prolactin (PRL) receptor cDNA. These cells (CHO-E32) expressed the long form of functional PRL receptor. Using microfluorimetric and patch-clamp techniques, we have investigated the effects of PRL on intracellular Ca2+ concentration ([Ca2+]i) and membrane ion conductances. Exposure of CHO-E32 cells to 5 nM PRL resulted in an increase in [Ca2+]i. Two types of response were observed: 1) a stimulation of Ca2+ entry and 2) an intracellular Ca2+ mobilization. As PRL inhibited voltage-activated Ca2+ current, the PRL-induced Ca2+ increase does not involve voltage-activated Ca2+ channels. PRL also increased a charybdotoxin-sensitive Ca(2+)-dependent K+ conductance. Simultaneous measurements showed that PRL hyperpolarized the membrane potential before increasing intracellular Ca2+ levels. In voltage clamp, hyperpolarizing voltage steps were associated with increased Ca2+ concentrations, whereas depolarizing voltage steps decreased [Ca2+]i. Cell-free patch-clamp experiments showed that PRL directly stimulates K+ channel activity. Our results suggest the existence of a regulatory complex involving a protein kinase tightly associated with the Ca(2+)-activated K+ channels and that PRL stimulates these channels by means of the activation of protein kinase. The resulting hyperpolarization stimulates Ca2+ entry, probably through voltage-insensitive nonspecific channels. |
| Databáze: | OpenAIRE |
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