EFFECT OF TRYPTOPHAN TREATMENT ON SELF-BITING AND CENTRAL-NERVOUS-SYSTEM SEROTONIN METABOLISM IN RHESUS-MONKEYS (MACACA-MULATTA)

Two studies were conducted to examine the effects of oral L-tryptophan (TRP) supplementation as a treatment for self-injurious behavior (SIB ) and to investigate behavior and central serotonin turnover of male r hesus monkeys. In Study One, TRP teas administered to seven individual ly housed rhesus monkeys with a recent history of spontaneous SIE. Whi le the monkeys were on TRP treatment (100 mg/kg twice a day), cisterna l cerebrospinal fluid (CSF) concentrations of 5-hydroxyindoleacetic ac id increased markedly (p = .0013) above baseline (baseline mean 207.6 pmol/ml +/- 39; TRP mean = 320.3 pmol/ml +/- 83.4), and the duration o f self-biting behavior decreased below baseline (p = .03). In Study Tw o, 14 individually housed rhesus monkeys without a history of SIB were placed on three different doses of TRP in random order (50, 100, and 200 mg/kg twice a day). TRP had no effect on any behavioral or biochem ical variables in the normal monkeys. Conclusions: Supplemental trypto phan in well-tolerated noses reduced self-biting and increases seroton in turnover rate in male monkeys with a recent history of SIB, The sam e doses of TRP do not effect behavior or serotonin metabolism in male monkeys without a history of SIB. Published by Elsevier Science Inc.