Fig. 5. ( A ) Bupivacaine (100 μm) reduced the current amplitude and the simultaneous application of retigabine (10 μm) and bupivacaine (100 μm) slowed the deactivation kinetic. Shown in the inset below the current recording is a scheme of the pulse protocol together with an original current trace elicited by the protocol. ( B ) The maximum current amplitude of the tail current under control conditions was −6.6 ± 3.5 nA; bupivacaine (100 μm) decreased the amplitude −4.0 ± 2.1 nA. Simultaneous application of bupivacaine (100 μm) and retigabine (10 μm) resulted in a current amplitude of −5.9 ± 2.5 nA (n = 6 paired experiments). ( C ) After simultaneous application of bupivacaine (100 μm) and retigabine (10 μm) the time constants for deactivation (85.8 ± 40.1 ms) were significantly larger than under control (13.4 ± 3.3 ms) as well as under bupivacaine (15.1 ± 2.9 ms) conditions (n = 10 paired experiments; P < 0.05). ( D ) The normalized charge (tail current versus time curve) under control conditions, under the influence of bupivacaine (100 μm), and during simultaneous application of retigabine (10 μm) and bupivacaine (100 μm) was plotted against the test potential.