. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Na-free B +60 -20 -40 mV , 030- 015- 005- D 100 Quinine O OS- 'S m 06- 0 1 3 10 RA Concentration {(iM) 10 100 Carbenoxolone (|iM) Figure 1. (A) Depolarizing voltage steps from —40 mV to +60 mV (inset) fail to reveal kemichannel currents in a Xenopus oocyte expressing Cx38. With the cell hathed in modified Earth's (MB) solution, passive ounvard currents are elicited with voltages up to +20 mV: with further depolarization (> +30 mV) onl\ inward currents are seen. The MB solution contained [in mM]
. The Biological bulletin. Biology; Zoology; Biology; Marine Biology. Na-free B +60 -20 -40 mV , 030- 015- 005- D 100 Quinine O OS- 'S m 06- 0 1 3 10 RA Concentration {(iM) 10 100 Carbenoxolone (|iM) Figure 1. (A) Depolarizing voltage steps from —40 mV to +60 mV (inset) fail to reveal kemichannel currents in a Xenopus oocyte expressing Cx38. With the cell hathed in modified Earth's (MB) solution, passive ounvard currents are elicited with voltages up to +20 mV: with further depolarization (> +30 mV) onl\ inward currents are seen. The MB solution contained [in mM]: NaCl 188]. KCI [II. NaHCO, [], N-2-hydroxyethylpiperazine-N'- 2-ethanesulfonic acid (HEPES) [15], Ca(NO,)2 [], CaCl2 [], and MgSO4 []: 10 mg/liter gentamycin was added, and the solution titrated with NaOH to (B) After replacing the bath solution with Na+-free (choline substitution) MB solution, voltage steps a 20 mV evoke voltage- and time-dependent hemichannel currents of increasing magnitude. (C) Hemicurrents enhanced by 200 jiiM quinine show no voltage-activated Na+ current. (D) The dose-response data for the full range of concentrations tested (5-1000 /u,M) are plotted on log-linear coordinates and fit by the Hill equation with an EC^i, of 150 /nM and a Hill coefficient of Error bars = ± SEM fn = 41 (E) Hemichannel currents were recorded in Na* -free MB with a single step protocol (depolarization from —40 mV to +40 mV) in response to various concentrations of retinoic acid (RA). The bar graph shows the averaged results from four cells in which currents were normalized to the maximum obtained in N a*-free MB. Error bars = +SEM. Over this limited range of concentrations, there is a dose-dependent block of hemichannel activity with half-maximal effect at approximately 2 ju,M RA. (F) Log-linear plot of the dose-dependent blockage of hemichannel activity bv Carbenoxolone. The hemichannel currents in Carbenoxolone were normalized to the mean curr
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Keywords: ., bookauthorlilliefrankrat, booksubjectbiology, booksubjectzoology
