Fig. 4.

4R inhibits ACh-evoked currents from the α7 nAChR. ACh-evoked currents were recorded from SHSY5Y cells transfected with human α7 nAChR, using the patch-clamp technique as explained in Methods. The cells were exposed to 300 μM ACh for 350 ms; 90s washouts with the external buffer separated successive applications of the agonist. 300 μM ACh evoked robust inward currents (first two recordings to the left). The cells were then exposed to 25 μM 4R in the absence of ACh for 120s; this was followed by application of 25 μM 4R in the presence of 300 μM ACh for 350 ms. 25 μM 4R produced a profound inhibition of the ACh-evoked current with full recovery upon washout as shown by the last two recordings.