Fig. 8.

I_h block by 5 mM CsCl or 100 μm ZD7288 increases LP-evoked IPSP amplitude in the PD cell. A: PSP amplitude at the end of PD polarization under control conditions (left) and in the presence of the I_h blocker 5 mM CsCl (right). B and C: IPSP amplitudes at the end of the PD current injection under control conditions (IPSP_{late control}) and increased IPSP amplitudes during I_h blockade with 5 mM Cs²⁺ (IPSP_{late 5mM Cs}) or ZD7288 (IPSP_{late 100μM Z7288}). For Cs²⁺, this effect was partially reversible through washout (IPSP_{late wash}). ★P < 0.05, control vs. blocker. D: during block of I_h with Cs²⁺, almost no difference was seen between IPSP amplitudes at the beginning (IPSP_{early 5mM Cs}) and at the end (IPSP_{late 5mM Cs}) of PD cell polarization. E and F: I_h blockade with Cs²⁺ (E) or ZD7288 (F) caused a small increase of IPSP amplitudes at the beginning of polarizing current injection, indicating that a small fraction of I_h channels were open. IPSP_{early control}, early IPSPs under control condition; IPSP_{early 5mM CS}, early IPSPs during I_h block with Cs²⁺; IPSP_{early 100μM ZD7288}, early IPSPs during I_h block with ZD7288. ★P < 0.05.