1. Effects of acetazolamide and concanamycin A on 5-HT-induced pHi changes.
Effects of acetazolamide and concanamycin A on 5-HT-induced pHi changes. (A) Bath application of 500 μmol l–1 acetazolamide causes a cytoplasmic acidification, whereas 10 nmol l–1 5-HT, applied in the presence of acetazolamide, produces an alkalinization. (B) In the presence of acetazolamide, 10 μmol l–1 8-CPT-cAMP induces an intracellular alkalinization. (C,D) Inhibition of the apical V-ATPase by 1 μmol l–1 concanamycin A causes a small acidification. In preparations in which 10 nmol l–1 5-HT induces a monophasic acidification (C), this pH change is almost unaffected by concanamycin A. When 10 nmol l–1 5-HT induces a multiphasic pH change, concanamycin A blocks the alkalizing response component (D). (E) Acetazolamide and concanamycin A applied together cause additive acidifications, and 10 nmol l–1 5-HT causes an alkalinization in the presence of these two inhibitors (E). The alkalinization produced by 10 nmol l–1 5-HT in the presence of acetazolamide is significantly (P<0.05) smaller when the V-ATPase is simultaneously inhibited by concanamycin A (F). Data in F are means ± s.e.m., N=9.
Bettina Schewe et al. J Exp Biol 2008;211:
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