Dyspnea sensation and chemical control of breathing in adult twins.
To examine possible genetic influence on the sensation of dyspnea and on load compensation, we conducted a twin study using healthy adult pairs (10 monozygotes, MZ, and 9 dizygotes, DZ). The ventilatory response to progressive hypercapnia (HCVR) was examined under three different conditions: hyperoxia (PETO2 > 150 mm Hg), hypoxia (PETO2 maintained at 50 to 55 mm Hg), and hyperoxia with an inspiratory flow-resistive load (17 mm H2O/L/s), with simultaneous assessment of the dyspnea sensation by visual analog scale (VAS). Although the VDZ/VMZ ratio (VMZ and VDZ are within-pair variances in MZ and DZ, respectively) for the slope value of the minute ventilation-PETCO2 regression line was not different from 1 in hyperoxia either with or without an inspiratory load, it was significantly larger than 1 in hypoxia (F = 5.17, p < 0.05), suggesting that a genetic influence on HCVR existed only in the presence of hypoxia. During 3% CO2 inhalation, the VDZ/VMZ ratio for the tidal volume (VT) was larger than 1 in hyperoxic HCVR with loading (F = 7.89, p < 0.01), and that for respiratory frequency (f) was larger than 1 only in hypoxic HCVR (F = 3.59, p < 0.05). At a PETCO2 of 55 mm Hg, the VT ratio was larger than 1 under all conditions (F = 5.91, p < 0.05; F = 6.99, p < 0.05; F = 3.75, p < 0.05; respectively), and the f ratio was significantly larger than 1 again only in hypoxic HCVR (F = 3.48, p < 0.05).(ABSTRACT TRUNCATED AT 250 WORDS)
Kobayashi
S
S
First Department of Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
Nishimura
M
M
Yamamoto
M
M
Akiyama
Y
Y
Kishi
F
F
Kawakami
Y
Y
D000328:Adult; D000368:Aged; D002245:Carbon Dioxide / Q000502:physiology*; D004417:Dyspnea / Q000235:genetics* / Q000503:physiopathology; D006801:Humans; D008875:Middle Aged; D010100:Oxygen / Q000502:physiology*; D012119:Respiration / Q000502:physiology*; D015656:Respiratory Mechanics; D012677:Sensation / Q000235:genetics*; D014427:Twins
D002245:Carbon Dioxide; D010100:Oxygen