A, Characteristic increases in [Ca2+]i produced by BK (20 nM) in Ca2+-free saline, in the absence and presence of lysosomal disruptor bafilomycin A1 (Baf); IP3R inhibitors xestospongin C (XeC) and 2-APB; or ryanodine receptor blocker, ryanodine (Avemary and Diener). B, Comparison of the effects of BK on [Ca2+]i induced by the treatments indicated in A, in cardiac vagal neurons; n = 6 neurons for each condition. P < 0.05 compared with the effect of BK alone or in the presence of Baf or Ry (*), and compared with the effect of BK alone and in the presence of other antagonists (Baf, XeC + 2-APB) (**).