Branched-chain amino acids increase the seizure threshold to picrotoxin in rats.

During infusion of branched-chain amino acids (BCAAs) in humans, changes in ventilatory drive, appetite, and sleep have been reported. The mechanism by which BCAAs exert their effects on CNS remains unclear. Picrotoxin is a proconvulsant drug, acting as an antagonist on the GABA-benzodiazepine receptor complex. Twenty rats were randomized to receive either an IP injection with 4% BCAAs (300 mg/kg; 8 ml/kg) (n = 10) or placebo (saline 8 ml/kg) (n = 10). The mean latency time from injection to onset of seizures was recorded as an indication of the seizure threshold. Latency time was significantly longer for BCAAs than for placebo, 11.2 (+/- 1.9) vs. 8.3 (+/- 1.8) min. Thus, a BCAA injection increased the seizure threshold to picrotoxin (p < 0.03). This suggests that BCAA infusion may exert effects on the GABA-benzodiazepine receptor complex.