FIG. 5.

ZD7288 and synaptic potentials in calyx afferents. A Evoked action potentials and spontaneous EPSPs recorded in current clamp in a calyx terminal. Action potentials typically occurred in response to (−100 pA, 20 ms duration) current injections presented every 1.2 s. Between spikes EPSPs were observed as upward deflections from rest (examples indicated by red arrows). B EPSPs were averaged before (black trace) and after (red trace) application of 100 μM ZD7288 to block I _h. Averages of a total of 171 events from three cells are shown. ZD7288 broadened mean EPSP width and increased the amplitude. C Action potentials were averaged before (21 action potentials, black trace) and after (17 action potentials, red trace) application of 100 μM ZD7288. D Spontaneous action potentials recorded in current clamp in a calyx terminal are followed by a slow hyperpolarization and subsequent depolarization to action potential threshold.