Effect of gamma aminobutyric acid on the carbon dioxide rebreathing response of normal subjects: a study using vigabatrin

Animal studies suggest that gamma aminobutyric acid (GABA) may be an important neurotransmitter in the control of respiration. Vigabatrin, a new drug for the treatment of epilepsy, is thought to exert its effect by increasing GABA concentrations in the brain. To assess the effect of increased GABA concentrations in the brain on human respiration we measured the ventilatory response to carbon dioxide in seven normal subjects after they had taken vigabatrin or placebo for three days in a double blind crossover study. There was no change in either the slope or the intercept of the curve of the ventilatory response to carbon dioxide after vigabatrin by comparison with placebo. This study suggests that GABA does not have an important role in the control of respiration in normal individuals.