Fig. 4
From: Basal Nucleotide Levels, Release, and Metabolism in Normal and Cystic Fibrosis Airways
The effect of nasal submucosal gland secretions on ATP concentration. (A) The ATP concentration measured in nasal lavages (not corrected for dilution) collected after stimulating submucosal gland (SMG) secretion with methacholine was reduced dramatically (closed column), relative to basal lavages (open column). (B) Exogenous ATP (1000 nM) added to nasal lavages rapidly disappeared only in those obtained after stimulating submucosal gland secretion (squares), compared with baseline lavages (triangles). Boiling the secretion-rich lavage abolished this enzyme activity (circles). (C) High performance liquid chromatography (HPLC) chromatogram demonstrating hydrolysis of the terminal phosphate group from [33P]γATP (100 µM) in a nasal lavage enriched with SMG secretions. (D) The total concentration of adenine nucleotides present in lavages before (open column) and after (closed column) SMG stimulation was determined by rephosphorylating all AMP and ADP in the sample to ATP, followed by the luciferin-luciferase assay.