Human G protein beta3 subunit variant does not alter hypercarbic or hypoxic ventilatory response.
Hypercarbic respiratory drive is mainly determined by PCO(2) and pH with activity of the intracellular Na+/H+ exchanger (NHE) playing an important role in maintaining intracellular pH and respiratory drive. Because NHE activity varies with genetically different G-protein beta3 subunits (GNB3) (C/T polymorphism at nucleotide position 825) different genotypes might alter respiratory regulation. To test the hypothesis that short-term ventilatory responses vary with different GNB3 healthy volunteers with different genotypes (CC, TC, TT) were exposed to either hyperoxic hypercarbia (n=33) or to isocapnic hypoxia (n=31), respectively. There was no difference between CC, TC, and TT genotypes in hypercarbic and hypoxic respiratory drive when assessed as the ratio of minute ventilation over endexpiratory PCO(2) changes (DeltaV.E/DeltaPETCO(2)), maximal tolerable PETCO(2), and ratio of changes in ventilation over arterial haemoglobin desaturation (DeltaV.E/DeltaSO(2)), respectively. Thus, short-term hypercarbic and hypoxic ventilatory drive do not differ between individuals with genotypes encoding different GNB3. Whilst respiratory control may still be influenced by G-protein aberration, other mechanisms seem to have a more important role in controlling ventilation.
Exner
H J
HJ
Abteilung für Anästhesiologie und Intensivmedizin, Universitätsklinikum Essen, Hufeland Strasse 55, D-45122 Essen, Germany.
Groeben
H
H
Rosskopf
D
D
Siffert
W
W
Peters
J
J
D005838:Genotype; D020962:Heterotrimeric GTP-Binding Proteins / Q000235:genetics / Q000502:physiology*; D006801:Humans; D006935:Hypercapnia / Q000235:genetics / Q000503:physiopathology*; D000860:Hypoxia / Q000235:genetics / Q000503:physiopathology*; D008297:Male; D010641:Phenotype; D011110:Polymorphism, Genetic / Q000502:physiology; D012119:Respiration; D015656:Respiratory Mechanics
D020962:Heterotrimeric GTP-Binding Proteins