EFFECTS OF VALINE, LEUCINE, ISOLEUCINE, AND A BALANCED AMINO-ACID SOLUTION ON THE SEIZURE THRESHOLD TO PICROTOXIN IN RATS

During infusion of branched-chain amino acids (BCAAs) in humans, chang es in ventilatory drive, sleeping pattern, and appetite have been repo rted. The mechanism by which BCAA exerts their effects on CNS remains unclear. An infusion of a BCAA solution (300 mg/kg) has previously bee n found to increase the seizure threshold in rats to the proconvulsant drug picrotoxin, an antagonist on the GABA-benzodiazepine receptor co mplex. In this study, each of the BCAAs given separately (valine, leuc ine, isoleucine; 300 mg/kg) (n = 10) increased the mean latency time t o onset of seizures vs. placebo as an indication of an increased seizu re threshold. A balanced amino acid solution (Vamin-Glucose(R)) had no effect on the seizure threshold. Thus, these CNS effects are specific for BCAAs and occur with all three.