Figure 1. Effects of extracellular Cs⁺ on post-train DAPs.

A, chart recording from a supraoptic neurone impaled in a superfused hypothalamic explant. Individual vertical deflections are spike trains (full amplitude not shown) comprising 3 action potentials each, evoked by a brief current pulse (0.2 nA, 50 ms). Each train is followed by a slowly decaying DAP. Note that consecutive application of 2 mM (lower bar) and 4 mM (upper bar) Cs⁺ provokes an increasing depolarization (dashed line; −59 mV) associated with progressive inhibition of DAPs. The traces in B are excerpts of the recording shown in A (lettered arrows) showing the DAPs recorded before (a), in the presence of 4 mM Cs⁺ (b), and following washout (c).