Diverse actions of calcitonin gene-related peptide on intracellular free Ca2+ concentrations in UMR 106 osteoblastic cells

T. Kawase, G. A. Howard, B. A. Roos, D. M. Burns

Research output: Contribution to journalArticle

23 Scopus citations

Abstract

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.

Original languageEnglish (US)
Pages (from-to)S379-S384
JournalBone
Volume16
Issue number4 SUPPL.
DOIs
StatePublished - Apr 1995

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Keywords

  • ATP-dependent potassium channel
  • Calcitonin gene-related peptide
  • Intracellular free calcium
  • Osteoblast-like cells
  • Osteosarcoma cells

ASJC Scopus subject areas

  • Physiology
  • Endocrinology, Diabetes and Metabolism
  • Histology
  • Hematology

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