Table 1. Effect of ionophores and bafilomycin A1 upon NAADP-induced pH_L responses.

Acridine Orange-loaded homogenate was stimulated by 1 μM NAADP, either after no treatment (control) or after preincubation with the indicated agents: 20 μM FCCP, 1 μM bafilomycin A1 (Baf), 10 μM valinomycin alone (Val), 10 μM valinomycin plus 2 μM FCCP, or 10 μM valinomycin plus 2 μM FCCP plus bafilomycin A1. Results are normalised to NAADP control responses and expressed as means±S.E.M. for the number of replications given in parentheses. *P<0.02, ***P<0.001 compared with NAADP controls. Elevated baseline values when NAADP was added were 35±5% (20 μM FCCP) and 45±4% (Val+FCCP), when expressed as a percentage of the maximal NH₄Cl. The relative baseline was not determined for all three agents simultaneously as preincubation was carried out ‘offline’ (but see Figure 5).

Preincubation	NAADP response (fold control)
FCCP	0.71±0.09 (9)***
Baf	1.52±0.09 (16)***
Val	1.03±0.19 (8)
Val+FCCP	0.69±0.07 (13)*
Val+FCCP+Baf	1.92±0.10 (11)***