Figure 8.

Effects various concentrations of tramadol on inward currents induced by GABA in bovine adrenal chromaffin cells. To know the effects of tramadol on the other ligand-gated ion channels, GABA_A receptors instead of nicotinic receptors were examined in adrenal chromaffin cells. (A) Tracings obtained from a single adrenal chromaffin cell show the effect of tramadol (10 μM) on 1 μM GABA-induced currents. (B) Effects of tramadol (1–100 μM) on 1 μM GABA-induced inward currents. GABA was applied for 20 s with or without 2 min treatment with various concentrations of tramadol (1–100 μM). Membrane potential was voltage-clamped at −60 mV (n=6).