Figure 6.

Application of 20 mM isoniazid depleted vesicular GABA over a period of 30–45 min. In the presence of 1 μM strychnine, IPSCs were evoked by extracellular stimulation. The traces illustrate an example of a recording of post-synaptic responses during the control period [trace (A)] and two epochs following isoniazid superfusion [traces (B) and (C)]. Mean responses are overlayed in black. Graph (D) plots the changes in amplitude, illustrating the time periods corresponding to (A–C), and shows a gradual but substantial reduction in current. The group data represented in graph (E) illustrates that evoked IPSCs in all motoneurons were progressively attenuated during the ∼40 min of isoniazid superfusion.