Effect of VSOR/VRAC blocker tamoxifen on contractile activity of primary neonatal cardiomyocytes and isolated perfused heart

Figures

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  Fig. 1. Effect of tamoxifen on the VSOR/VRAC currents activated in neonatal cardiac myocytes upon osmotic swelling. A Time course of whole-cell current activation in response to cell swelling. Currents were elicited by application of alternating pulses from 0 to ± 40 mV (every 5 s). At the time points indicated by arrows the test pulses were applied as follows: the holding potential was 0 mV; after a pre-pulse to ‒100 mV (500 ms), currents were elicited by application of pulses (1000 ms) from ‒100 to + 100 mV in 20-mV increments. B Instantaneous current-to-voltage relationships of the VSOR/VRAC currents activated in neonatal cardiac myocytes upon osmotic swelling in the absence (Control) and presence of tamoxifen. Currents were measured at the beginning of the current responses to the test pulses (similar to those shown in panel A). (C) Average VSOR/VRAC currents measured at ± 40 mV in the absence (Control) and presence of tamoxifen. *Significantly different from Control at p < 0.05 (unpaired t-test)

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  Fig. 2. Effect of tamoxifen on contractile activity of neonatal cardiac myocytes. A phase-contrast image of the neonatal cardiac myocytes in primary culture. Red line marks the cell for which contractile activity is shown in (B). Yellow lines mark other contracting cells in the field. B Original recording of the contractile activity of single cardiomyocyte in before (Control) and after application of tamoxifen as indicated. C Contraction frequency of cardiomyocyte contraction before (Control) and after application of tamoxifen. D Average amplitude of cardiomyocyte contraction before (Control) and after application of tamoxifen. *Significantly different from Control at p < 0.05 (unpaired t-test)

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  Fig. 3. Effect of tamoxifen on contractile activity of Langendorff perfused hearts. A Original recording of the contractile activity of an isolated perfused heart before (Control) and after application of tamoxifen as indicated. B, C, D, E, F, G Parameters of the contractile activity of isolated perfused hearts before (Control) and after application of tamoxifen. The meaning of each parameter shown on the ordinates is explained in the Results section. *Significantly different from Control at p < 0.05 (paired t-test)