Fig. 6.
Acid-evoked currents recorded by whole cell patch clamp from muscle afferents are potentiated after muscle incision. (A) Representative currents evoked by indicated pH solutions from a control solution of pH 7.4 in labeled skeletal muscle afferents in primary dissociated culture of dorsal root ganglia neurons collected 2 weeks after injection of 1,1-dioctadecyl-3,3,3,3 tetramethylindocarbocyanine perchlorate (DiI) into the rat gastrocnemius muscle. (B) Median (interquartile range) peak amplitudes evoked by the indicated pH solutions in muscle afferents from control (sham) rats and rats having undergone muscle incision (n = 27 total cells from 5 sham rats, and n = 28 total cells from 5 incision rats). *P < 0.05 compared with sham data at the same pH. Dorsal root ganglia of afferents from incised rats were different from sham for pH 6.0 (P = 0.021), pH 6.5 (P = 0.039), pH 6.8 (P = 0.028), and pH 7.0 (P = 0.018). (C) Mean amplitudes of the sustained current evoked by the indicated pH solutions (measured at the end of a 5-s application) from sham and incision muscle afferents (n = 33). (D) The mean ratios of the sustained to the peak current amplitudes evoked by the indicated pH solutions from sham and incision muscle afferents (n = 28). *P < 0.05 compared with sham data at the same pH. (E) The mean ratios of pH 5-evoked current amplitudes in the presence of the acid-sensing ion channels, antagonist (amiloride 300 μm) or the transient receptor vanilloid receptor 1 antagonist (AMG9810 1 μm) compared with the amplitude of the previous pH 5 application in the absence of drug from sham and incision muscle afferents (n = 12). *P < 0.05 and **P < 0.01 compared with the previous pH 5 application in the absence of drug. P < 0.05 comparing amiloride inhibition in sham versus incision muscle afferents. (F) pH dose–response data for pH-evoked currents in sham and incision muscle afferents. Data were normalized to the peak currents evoked by pH 5. Lines are fits of the Hill equation of the means (n ≥ 28). (G) Mean time constants (τ) of desensitization as measured from single exponential fits to the falling phase of the transient currents evoked by the indicated pH solutions in sham and incision muscle afferents (n ≥ 28). (H) Mean recovery from desensitization data for sham and incision muscle afferents (n ≥ 12). Current was desensitized with a 7-s application of pH 6. Cells were then exposed to pH 7.4 solution for the indicated times before they were stimulated again with pH 6. Recovery is the percentage of current evoked by the second pH 6 application compared with the first. Lines are fits of single exponentials of the means (τ = 0.31 s and 0.30 s for sham and incision data, respectively). Desens. = desensitization; I = current; nA = nanoamp; Sust = sustained.

Acid-evoked currents recorded by whole cell patch clamp from muscle afferents are potentiated after muscle incision. (A) Representative currents evoked by indicated pH solutions from a control solution of pH 7.4 in labeled skeletal muscle afferents in primary dissociated culture of dorsal root ganglia neurons collected 2 weeks after injection of 1,1-dioctadecyl-3,3,3,3 tetramethylindocarbocyanine perchlorate (DiI) into the rat gastrocnemius muscle. (B) Median (interquartile range) peak amplitudes evoked by the indicated pH solutions in muscle afferents from control (sham) rats and rats having undergone muscle incision (n = 27 total cells from 5 sham rats, and n = 28 total cells from 5 incision rats). *P < 0.05 compared with sham data at the same pH. Dorsal root ganglia of afferents from incised rats were different from sham for pH 6.0 (P = 0.021), pH 6.5 (P = 0.039), pH 6.8 (P = 0.028), and pH 7.0 (P = 0.018). (C) Mean amplitudes of the sustained current evoked by the indicated pH solutions (measured at the end of a 5-s application) from sham and incision muscle afferents (n = 33). (D) The mean ratios of the sustained to the peak current amplitudes evoked by the indicated pH solutions from sham and incision muscle afferents (n = 28). *P < 0.05 compared with sham data at the same pH. (E) The mean ratios of pH 5-evoked current amplitudes in the presence of the acid-sensing ion channels, antagonist (amiloride 300 μm) or the transient receptor vanilloid receptor 1 antagonist (AMG9810 1 μm) compared with the amplitude of the previous pH 5 application in the absence of drug from sham and incision muscle afferents (n = 12). *P < 0.05 and **P < 0.01 compared with the previous pH 5 application in the absence of drug. P < 0.05 comparing amiloride inhibition in sham versus incision muscle afferents. (F) pH dose–response data for pH-evoked currents in sham and incision muscle afferents. Data were normalized to the peak currents evoked by pH 5. Lines are fits of the Hill equation of the means (n ≥ 28). (G) Mean time constants (τ) of desensitization as measured from single exponential fits to the falling phase of the transient currents evoked by the indicated pH solutions in sham and incision muscle afferents (n ≥ 28). (H) Mean recovery from desensitization data for sham and incision muscle afferents (n ≥ 12). Current was desensitized with a 7-s application of pH 6. Cells were then exposed to pH 7.4 solution for the indicated times before they were stimulated again with pH 6. Recovery is the percentage of current evoked by the second pH 6 application compared with the first. Lines are fits of single exponentials of the means (τ = 0.31 s and 0.30 s for sham and incision data, respectively). Desens. = desensitization; I = current; nA = nanoamp; Sust = sustained.

Close Modal
This Feature Is Available To Subscribers Only

or Create an Account

Close Modal
Close Modal