Fig. 6. Effect of concanamycin A on 5-HT-induced pH changes for salivary glands with HAF in their apical membrane domain. (A) Incubation in 1 µmol l^–1 concanamycin A/0.02% DMSO (ConA) inhibited the 5-HT-induced changes in F₄₇₀/F₄₁₀ ratio almost completely. (B) Control gland, exposed to the same experimental conditions but treated with DMSO only. (C) Quantitative analysis of the effect of concanamycin A (ConA) or 0.02% DMSO (Control) on the basal F₄₇₀/F₄₁₀ ratio. Values (means ± s.d., N=6) represent the difference in F₄₇₀/F₄₁₀ ratio before and after exposure to concanamycin A or DMSO, but before the second 5-HT stimulus. (D) Quantitative analysis of the effect of concanamycin A on the 5-HT-induced acidification. Response to 5-HT in the presence of concanamycin A/0.02% DMSO (ConA) or 0.02% DMSO only (Control) was normalized to the response induced by the initial 5-HT stimulus. Values represent means ± s.d. (N=6).