Figure 3. Abolition of subthreshold oscillations by serotonin is mediated postsynaptically.
Under control conditions (Phase 1), the olivary neurone represented here had a membrane potential of -58 mV and showed 6 Hz subthreshold oscillations. In Phase 2, addition of 1 μM TTX did not significantly affect the resting potential or the oscillation. In Phase 3, application 50 μM serotonin and 1 μM TTX abolished the oscillations and depolarized the membrane to -48 mV. Returning the membrane potential to -58 mV did not restore the oscillation. In Phase 4, serotonin was removed from the bath and the oscillations returned.