Figure 2. BDNF enhances ASIC1a-mediated currents through activation of PI3K-Akt pathway. Perforated electrophysiological recordings were performed. A, The amplitude of the ASIC current (I6.0) in cultured mouse SDH neurons was enhanced by bath application of BDNF (20 ng/ml), but not a control standard extracellular solution (ES), for 5 min. Inset, Examples of ASIC current traces recorded from one neuron at different times before and after BDNF treatment. Data were normalized to the mean amplitude of I6.0 before BDNF treatment (dashed line here and in B–F). #p < 0.05, ###p < 0.001, n = 8–15, by Student's paired t test. B, Blockade of TrkB receptor with either K252a (n = 15) or by transfecting TrkB-T1 (n = 6) abolished the enhancement caused by BDNF treatment for 5 min (n = 15). ###p < 0.001, versus the amplitude of I6.0 before BDNF treatment, by Student's paired t test. **p < 0.01, ***p < 0.001, versus BDNF-treated group, by Student's unpaired t test. C, Summary of effects of various pharmacological treatments on I6.0 at 5 min after the onset of BDNF. **p < 0.01, ***p < 0.001 versus BDNF only (n = 4–15, Student's unpaired t test). NS, No significant difference. D, Blockade of Akt activity with either Akt inhibitor IV (n = 4) or by transfecting DN-Akt (n = 6) abolished the enhancement caused by BDNF. ###p < 0.001, versus before BDNF treatment, by Student's paired t test. *p < 0.05, ***p < 0.001, versus BDNF-treated group, by Student's unpaired t test. E, Sample traces and summary data showing that bath application of BDNF for 5 min (n = 7) enhanced ASIC1a current in CHO cells co-transfected with TrkB and ASIC1a, which was abolished by K252a (n = 7) and not seen if TrkB was omitted in the transfection (n = 6). ##p < 0.01, versus before BDNF treatment, by Student's paired t test. **p < 0.01, versus ASIC1a + TrkB without K252a, by Student's unpaired t test. F, Summary of effects of various pharmacological treatments on I6.0 at 5 min after the onset of BDNF in CHO cells that coexpressed ASIC1a and TrkB (same as in B). n = 5–9, **p < 0.01, versus BDNF only, by Student's unpaired t test.