Characteristics of acid‐sensing ion channel currents in male rat muscle dorsal root ganglion neurons following ischemia/reperfusion

Figures

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  FIGURE 1. ASIC currents in rat muscle DRG neurons. (a) The representative traces of ASIC1a‐like currents (left) and ASIC3‐like currents (right) in rat muscle DRG neurons at pH 6.7 before and after 30 nM PcTx1 (antagonist to ASIC1a channels), and 1 μM APETx2 (antagonist to ASIC3 channels) applied for 10 s. PcTx1 and APETx2 were pre‐applied for 1 min, followed by application of pH 6.7 for 10 s, respectively. (b) The aligned plot of the current density of ASIC1a‐like currents before and after 30 nM PcTx1 applied. *p < 0.05, comparing between pH 6.7 and pH 6.7 plus antagonist with a paired t‐test analysis. (c): The aligned plot of the current density of ASIC3‐like currents before and after 1 μM APETx2 applied. *p < 0.05, comparing between pH 6.7 and pH 6.7 plus antagonist with a paired t‐test analysis. (d) The inactivation time constants of ASIC1a‐like currents and ASIC3‐like currents at pH 6.7 before and after application of 30 nM PcTx1 and 1 μM APETx2, respectively. NS indicates no significant difference (analyzed with a paired t‐test) observed in inactivation time constants of ASIC1a and ASIC3 currents before and after the application of their respective antagonists.

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  FIGURE 2. Effect of hindlimb I/R and ischemia on the distribution of IB4+ and IB4− muscle DRG neurons. (a) The representatives of IB4+ muscle DRG neurons (orange), IB4− muscle DRG neurons (red), and IB4+ DRG neurons with no DiI label (green). Scale bar: 50 μm. (b) The histogram shows the proportion of IB4+ and IB4− muscle DRG neurons in the control, I/R, and FAO groups. IB4+ and IB4− muscle DRG neurons were randomly numbered from 20 version fields in five coverslips. The number of IB4+, IB4− neurons, and total counted neurons was listed in histogram. No significant difference among the groups when analyzed with chi‐squared test.

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  FIGURE 3. Effect of hindlimb I/R and ischemia on the distribution of ASIC1a and ASIC3 currents in rat muscle DRG neurons. (a, b) The distribution of ASIC currents in IB4− and IB4+ rat muscle DRG neurons at pH 6.7 and pH 5.5 in the control, I/R, and ischemia groups. The number of ASIC neurons and total recorded neurons were shown in histograms. *p < 0.001 between IB4− neurons and IB4+ neurons in each group when analyzed with chi‐squared test. (c, d) The distribution of ASIC1a‐ and ASIC3‐like currents in IB4− and IB4+ muscle DRG neurons in the control, I/R, and FAO groups. *p < 0.05 between the two groups indicated, using analysis of chi‐squared test.

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  FIGURE 4. Effect of hindlimb I/R and ischemia on the activities of ASIC currents in rat muscle DRG neurons. (a) The histogram of the averaged current density of ASIC1a‐like currents in IB4− and IB4+ muscle neurons at pH 6.7 (left) and pH 5.5 (right) in the control, I/R, and FAO rats. When analyzed with ANOVA, results show no significant difference observed among the three groups either application of pH 6.7 or pH 5.5 solution. (b) The histogram of the averaged current density of ASIC3‐like currents in IB4− and IB4+ muscle neurons at pH 6.7 (left) and pH 5.5 (right) in the control, I/R, and ischemic rats. *p < 0.05 between the two groups when analyzed with ANOVA. There was no significant difference in current density of ASIC3‐like currents in IB4+ DRG neurons observed among the three groups either application of pH 6.7 or pH 5.5 solution. Note that the induced inward currents >50 pA when pH 6.7 or 5.5 applied were analyzed.

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  FIGURE 5. Representative traces of ASIC1a‐like currents and ASIC3‐like currents in IB4− muscle DRG neurons of the control, I/R, and FAO groups. Each trace was recorded from one individual muscle DRG neuron of control, I/R, and FAO.