A, summary of the DHPG-induced calcium-current facilitation in the presence of calcium store-depleting drugs, thapsigargin (thap: n= 10; DMSO control: n= 9), CPA (CPA: n= 9; DMSO control: n= 9), caffeine (caffeine: n= 9; control: n= 8) and BaCl2 (BaCl2: n= 7; CaCl2 control: n= 7). *P < 0.05. B, time course of the DHPG (horizontal bar)-induced calcium-current facilitation in the presence (filled circles) and the absence (open circles) of caffeine. C, the DHPG-induced calcium-current facilitation in the presence (filled circles; n= 9) and the absence (open circles; n= 8) of 2-APB, an InsP3R inhibitor. D, the DHPG-induced calcium-current facilitation in the presence (filled circles; n = 7) and the absence (open circles; n= 7) of TMB-8, a RyR inhibitor.