Redox regulation of neurovascular function by acetazolamide : complementary insight into mechanisms underlying high-altitude acclimatisation

Letter to the editor: We read with interest the study by Fan and colleagues describing how the carbonic anhydrase (CA) inhibitor acetazolamide reduced periodic breathing and accelerated acclimatisation to high altitude in native lowlanders (Fan et al. 2012). Intravenous infusion was shown to increase resting cerebral blood flow (CBF) and cerebrovascular reactivity to carbon dioxide (CVRCO2 ) independently of altered peripheral or central chemoreflex sensitivity. The authors concluded that the improvement in breathing stability was attributable to an increase in the 'CO2 reserve'. We would like to extend their elegant findings by suggesting a complementary mechanism albeit secondary to classical CA inhibition that may have equally contributed to the neurovascular benefits as observed.