Figure 5. N-desmethyl tamoxifen inhibits DRG action potential amplitude and frequency.
A) Exemplar action potentials recorded from an isolated DRG neuron in control and ND-Tam-treated conditions using a 1 second, 80 pA injection of current. After the experiment was complete, drug was washed out of the bath for five minutes and recovery from inhibition was retested. Consistent with previous reports, the resting membrane potential of the DRG neurons was −59.2 ± 5 mV (Error is equal to S.D., n = 109)(Wang et al., 1994). B, C) The potency of ND-Tam inhibition on DRG action potential frequency and peak amplitude. Open symbols represent responses from individual cells while filled symbols represent average response per concentration. Error is equal to S.E.M. and the number of cells evaluated per treatment group is indicated within the parentheses. D, E) A comparison of the potency of lidocaine (Lid.), cannabidiol (CBD) and carbamazepine (CBZ) inhibition on action potential frequency and peak amplitude. Drug concentration-INa inhibition relationships are fit to the Hill equation. The corresponding half-maximal inhibitory concentrations (IC50) for each drug are listed in Supplemental Table 3. Open symbols represent responses from individual cells and filled symbols represent average response per concentration. Error is equal to S.E.M. and the number of cells evaluated per treatment group are indicated within the parentheses.