Respiratory and sleep patterns during nocturnal infusions of branched chain amino acids

In the awake, normal subject, infusions of branched chain amino acids (BCAA) alter the ventilatory response to CO2. If this effect extends to the sleep state, it could contribute to our understanding of the neurophysiology of the sleep state as well as having clinical utility in ameliorating or preventing apnea syndromes. This study examined the effect of nocturnal BCAA infusion on sleep patterns (as measured by EEG, chest wall motion, Sao2 and end-tidal CO2) in five normal male subjects. Subjects were monitored with a polysomnograph from 21.00 to 7.00. Each subject was studied double-blind in random order on three occasions: a) baseline, no infusion (B); b) control, with normal saline infusion (S); and c) treatment, infusion of BCAA (BCAA). Sleep pattern analysis did not demonstrate any measurable effect of the BCAA infusion. End-tidal CO2 levels during BCAA infusion were lower than during baseline or control nights (mean +/- s.d.; BCAA: 5.8 +/- 0.7 kPa vs. B: 6.9 +/- 0.1 kPa, P less than 0.01 and S: 6.7 +/- 0.4 kPa, P less than 0.05). This study demonstrates that nocturnal BCAA infusions have effects on respiratory control during sleep; further clinical studies are required to determine whether these data have implications for disease states.