Diverse Actions of Calcitonin Gene-Related Peptide on Intracellular Free Ca2+ Concentrations in UMR 106 Osteoblastic Cells
| Autor: | T, Kawase, G A, Howard, B A, Roos, D M, Burns |
|---|---|
| Rok vydání: | 1995 |
| Předmět: |
Calcitonin
Osteosarcoma Osteoblasts Potassium Channels Histology Dose-Response Relationship Drug Physiology Calcitonin Gene-Related Peptide Pinacidil Vasodilator Agents Endocrinology Diabetes and Metabolism Colforsin Bone Neoplasms Guanidines Rats Adenosine Triphosphate Spectrometry Fluorescence Glyburide Potassium Tumor Cells Cultured Animals Calcium Fura-2 Egtazic Acid |
| Zdroj: | Bone. 16:379S-384S |
| ISSN: | 8756-3282 |
| DOI: | 10.1016/8756-3282(95)00016-7 |
| Popis: | Calcitonin gene-related peptide (CGRP) was examined for its effects on intracellular free Ca2+ concentration ([Ca2+]i) in UMR 106 osteoblast-like cells. Cells loaded with the Ca2+ dye FURA-2 dose-dependently responded to CGRP (1-100 nM) with transient two-fold increases in [Ca2+]i. An intracellular source for this Ca2+ transient was suggested by the failure of membrane depolarization with high extracellular K+ or acute depletion of extracellular Ca2+ ([Ca2+]e) with EGTA to attenuate this response. After cells were incubated for 45 min with 0.1 mM extracellular Ca2+ to deplete intracellular Ca2+ stores, CGRP produced a 25-30% decrease in [Ca2+]i rather than a transient increase. This calcium decrease was mimicked by membrane depolarization or by pinacidil, a specific activator of adenosine triphosphate (ATP)-sensitive potassium (KATP) channels, and blocked by glybenclamide, a specific blocker of KATP channels. Our data suggest that CGRP has diverse Ca2+ regulatory effects in UMR 106 cells, mobilizing Ca2+ from intracellular stores via classical signaling while possibly promoting cellular Ca2+ efflux or inhibiting uptake through voltage-dependent Ca2+ channels via KATP-mediated hyperpolarization. |
| Databáze: | OpenAIRE |
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