Figure 5.

Acute Morphine Challenge Does Not Alter the Voltage Dependence of Activation of TTX-R Na⁺ Channels

Relative conductances (G/G_max) of TTX-R Na⁺ channels at baseline (black) and following acute morphine challenge (3 μM, red). Values transformed from I-V curves are plotted as a function of the step potential and fit with a Boltzmann function (see Transparent Methods). No significant shifts in the voltage of half-maximum (V_1/2) activation, slope factor (k), or Boltzmann fit parameters are noted in any of the treatment cohorts following acute morphine challenge. PP + SAL (N = 7, n = 7), PP + VAN (N = 4, n = 6), MP + SAL (N = 7, n = 9), MP + VAN (N = 5, n = 7), analyzed by two-way repeated-measures ANOVA with Bonferroni post hoc analysis and ordinary least squares non-linear regression; data expressed as mean ± SEM (see Table S3 for additional values).