Increased sodium–proton antiporter activity in patients with obstructive sleep apnoea

• Published in: Journal of sleep research Vol. 9; no. 3; pp. 285 - 291
• Main Authors: Tepel, Martin, Sanner, Bernd M., Van Der Giet, Marcus, Zidek, Walter
• Format: Journal Article
• Language: English
• Published: Oxford UK Blackwell Science Ltd 01.09.2000
• Subjects: Aged; Antiporters - blood; Cytosol - metabolism; Electromyography; Female; fluorescent dye; Fluorescent Dyes; Humans; Hydrogen-Ion Concentration; Ion Transport - physiology; lymphocytes; Lymphocytes - metabolism; Male; Middle Aged; obstructive sleep apnoea; Polysomnography; Protons; Sleep - physiology; Sleep Apnea, Obstructive - blood; Sodium Chloride - blood; sodium–proton antiporter
• ISSN: 0962-1105; 1365-2869
• DOI: 10.1046/j.1365-2869.2000.00207.x

Cytosolic pH (pHi) and the activity of the sodium–proton antiporter (Na+/H+ antiporter) were measured in lymphocytes from 22 patients with obstructive sleep apnoea and from 24 age‐matched healthy subjects (Controls). The cellular Na+/H+ antiporter was measured spectrophotometrically using a pH‐sensitive fluorescent dye after intracellular acidification using sodium propionate. Resting pHi was similar in lymphocytes from patients with obstructive sleep apnoea and from controls (7.36 ± 0.20, n=22; vs. 7.35 ± 0.19, n=24; mean ± SD). The Na+/H+ antiporter activity was significantly higher in patients with obstructive sleep apnoea than in controls (11.87 ± 3.26 × 10–3 pHi/s vs. 4.38 ± 1.40 × 10–3 pHi/s; P < 0.0001). The apparent affinity of the Na+/H+ antiporter was not significantly different between the groups (6.90 ± 0.23 vs. 6.87 ± 0.20). In patients with obstructive sleep apnoea the activity of the Na+/H+ antiporter remained stable during the night. The activity of the Na+/H+ antiporter was 13.49 ± 4.80 × 10–3 pHi/s at 20.00 and 13.26 ± 6.13 × 10–3 pHi/s at 02.00. From the present results it is concluded that an increased cellular Na+/H+ antiporter activity may be a genetic marker for patients who are predisposed to obstructive sleep apnoea.