Membrane potential of rat calvaria bone cells: Dependence on temperature

Massas, R.; Korenstein, Rafi; Bincmann, Dieter; Tetsch, P

doi:10.1002/jcp.1041440102

Cited by 10 publications

(2 citation statements)

References 21 publications

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“…These osteoblastic cells were originated and located at various anatomical sites of the skeleton. The calvarial osteoblasts were characterized by their response to PTH and their alkaline phosphatase level [Massas et al, 1993] as well as their membrane potential properties [Bingmann et al, 1988;Tetsch et al, 1989;Massas et al, 1990]. The marrow stromal osteoblasts were studied using the MBA-15 cell line.…”

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confidence: 99%

Estrogen modulation of osteoblastic cell-to-cell communication

1998

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Two osteoblastic cell populations, calvarial and marrow stromal cells, were exposed to estrogen derivatives in vitro. The hormonal effect was monitored by following intracellular Ca+2 levels [Ca+2]i and gap-junction communication. We measured fast changes in intracellular Ca+2 levels in response, of these cells, to the steroid hormones. The changes were dose dependent revealing maximal activity at 100 pM by 17-beta-Estradiol and 1 nM by estradiol-CMO. Additionally, the effect of estrogen, on functional coupling of the cells, was measured using fluorescence dye migration and counting the number of neighboring cells coupled by gap junctions. An uncoupling effect was demonstrated in response of these cells to estrogen treatment. The quick stereospecific effect was achieved in the presence of 17-beta-estradiol but not in the presence of 17-alpha-estradiol. These results suggest the involvement of plasma membrane receptors in addition to the already known nuclear receptors in transducing the hormone effects in the osteoblastic cells.

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confidence: 99%

Estrogen modulation of osteoblastic cell-to-cell communication

1998

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“…Bone cells in vivo exhibit cell-cell communication via gap junctions [1] which allow the exchange of ions and small molecules, such as second messengers, between neighboring cells [2] in response to hormonal or bioelectric signals [3][4][5][6][7][8]. Previous investigations revealed the structure of gap junctions between osteoblast-like cells (OB) in vitro by electron microscopic, immunocytochemical, and biochemical analysis [9].…”

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Dye and electric coupling between osteoblast-like cells in culture

Schirrmacher

Brümmer²,

Düsing

et al. 1993

Calcif Tissue Int

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Primary cultures of osteoblast-like cells (OB) derived from calvarial fragments of newborn rats and juvenile guinea pigs formed numerous gap junctions between neighboring cells in vitro. Intracellular injection of Lucifer yellow led to a staining of up to 30 adjacent cells. Parallel intracellular recordings showed that amplitudes of stimulated membrane potential changes (4-5 mV) were closely related between coupled cells. The coupling factor, which was derived from the ratio of these amplitudes, ranged between 0.1 and 0.8. The coupling factor (1) was not dependent on the membrane potential or the injected current strength; (2) strong acidosis (pH < 6.6) and hypercapnia (pCO2 > 80 mm Hg) did not affect electric or dye coupling; (3) elevation of intracellular cAMP level was ineffective; (4) rise of the extra- and intracellular Ca2+ concentration did not effect the electric coupling; (5) the anticonvulsant drugs carbamazepine and phenytoin impaired the coupling factor up to 59%. The findings show that cell-cell communication between OB via gap junctions proved stable under various conditions which, in other tissues, were found to reduce the coupling strength of gap junctions.

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Regulation of cell-cell communication in rat bone cells: The effect of phorbol esters

1999

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The skin tumor promoter 12-O-tetradecanoylphorbol-13-acetate (TPA) is a potent inhibitor of gap junctional intercellular communication. In the present study, the inhibition of cell-cell communication by TPA has been investigated in primary bone cells from newborn rat calvaria, with an emphasis on the involvement of intracellular pH (pH(i)) and cytosolic calcium ([Ca(+2)](i)) in this process. The results show that TPA (5 x 10(-)(8) M) caused a complete inhibition of intercellular communication within 40-60 min. The intercellular communication was fully restored after overnight incubation in the presence of TPA. This effect was found to be associated with an elevation of pH(i). However, neither an increase of pH(i) alone nor exposure to TPA, under conditions preventing pH(i)-shift, were found to affect intercellular communication. It is suggested that the inhibition of intercellular communication, in the presence of TPA, depends on the pH(i)-shift itself rather than on the absolute value of pH(i). In addition, elevation of cytosolic calcium by ionomycin led to the termination of intercellular communication after 30 min. This inhibitory effect was abolished when the cells were incubated for overnight with TPA and then intracellular calcium was elevated by the addition of ionomycin. These results indicate that shift of pH(i) and the increase of intracellular calcium are involved in repression of intercellular communication by TPA.

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Membrane potential of rat calvaria bone cells: Dependence on temperature

Cited by 10 publications

References 21 publications

Estrogen modulation of osteoblastic cell-to-cell communication

Estrogen modulation of osteoblastic cell-to-cell communication

Dye and electric coupling between osteoblast-like cells in culture

Regulation of cell-cell communication in rat bone cells: The effect of phorbol esters

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