Table 4.

Effect of apical HCO₃⁻ on unidirectional ³⁶Cl⁻ fluxes across Calu-3 cells under open-circuit conditions

	Jsm	Jms	Jnet	Ieq	RT	VT
Control 25 HCO3−	0.85 ± 0.10	0.77 ± 0.16	0.08 ± 0.10	0.78 ± 0.11	364 ± 23	−7.61 ± 0.61
Forskolin 25 HCO3−	1.75 ± 0.18***	1.60 ± 0.18***	0.15 ± 0.17	2.70 ± 0.14***	266 ± 14***	−19.26 ± 0.63***
Forskolin 30 HCO3−	1.53 ± 0.12++	1.27 ± 0.10+++	0.25 ± 0.11++	2.71 ± 0.12	262 ± 16	−19.03 ± 0.74
Forskolin 50 HCO3−	2.77 ± 0.15†††	2.50 ± 0.10†††	0.27 ± 0.13	2.75 ± 0.14	254 ± 20	−18.73 ± 0.56

Monolayers were bathed with symmetrical 25 m HCO₃⁻, then with 30 or 50 mmol l⁻¹ HCO₃⁻ on the apical side; 10 μmol l⁻¹ forskolin was added to both sides. J_sm, J_ms, J_net, I_eq: μeq cm⁻² h⁻¹; R_t: ohms cm² h⁻¹. Values are mean ± SEM. ***P < 0.001, forskolin (25 HCO₃⁻) vs. control. ^{++, +++}, P < 0.01, P < 0.001, forskolin (30 HCO₃⁻) vs. forskolin (25 HCO₃⁻). ^†††P < 0.001, forskolin (50 HCO₃⁻) vs. forskolin (30 HCO₃⁻), control and forskolin (25 HCO₃⁻) (n= 8 each) and forskolin (30 HCO₃⁻) and forskolin (50 HCO₃⁻) (n= 4 each).