Inhibiting calcium release from internal stores occludes the effect of ACh on mEPSCs onto Hcrt+ neurons. A, B, mEPSCs recorded at baseline (A) and after 30 min incubation with the ryanodine receptor antagonist dantrolene (50 μM) and the IP3 receptor antagonist (−)-Xestospongin C (5 μM; B). C, D, Mean values of amplitude (C) and instantaneous frequency (D) of mEPSCs at baseline, after 30 min incubation with dantrolene (Dan) and XeC and upon subsequent ACh puff in the continued presence of dantrolene and XeC. n = 3 cells. Both amplitude and instantaneous frequency were significantly decreased by dantrolene+XeC, but there was no significant difference between mEPSC recordings in the presence of dantrolene and XeC and upon subsequent ACh puffs in the continued presence of these inhibitors. **p < 0.01; NS, not significant (p > 0.05).