Figure 3. TRAM-34 has no significant effects on the medium afterhyperpolarization (mAHP) or slow afterhyperpolarization (sAHP) in CA1 pyramidal cells.
(A) Brief spike trains (7 spikes/100 ms) were evoked by depolarizing current pulses from a holding potential of -70 mV. Black and red traces represent recordings from two pyramidal cells, in control medium and after incubation with TRAM-34 (1µM) for 30 minutes. Inset, showing mAHP(⚫) and sAHP (▲) at an enlarged scale. (B) mAHP and sAHP amplitudes were not significantly different between control and TRAM-34 treated groups. Data are given as, mean ± SEM. (C) Representative traces of the effect of TRAM-34 (1 µM, red) and noradrenaline (NA, 10 µM, blue) on the mAHP and sAHP in CA1 pyramidal neurons. (D) Time course of the sAHP amplitude measured in panel A. Bath application of TRAM-34 (1 µM) for 25 min did not significantly reduce the sAHP (n = 5). However, subsequent application of noradrenaline (NA, blue line) rapidly eliminated the sAHP. (E) Summary bar plots showing the sAHP amplitude averaged over a period of five minutes during control (black bar), TRAM-34 (red bar) and NA (blue bar) application. The averaged periods are represented by color bottom lines in panel D.