P. Knott, M. H. Joseph, G. Curzon
Jan 1, 1973
Citations
0
Influential Citations
41
Citations
Journal
Journal of Neurochemistry
Abstract
TRYPTOPHAN is an amino acid with a special role in the brain as its hydroxylation is the rate limiting step in the synthesis of 5-hydroxytryptamine (5-HT) (MOIR and ECCLESTON, 1968). The responsible enzyme, tryptophan hydroxylase (tryptophan-5-hydroxylase, EC 1.14.3) is unsaturated under physiological conditions and, therefore, brain 5-HT turnover may be increased by increasing brain tryptophan. Recently it has been shown that various drugs which increase brain 5-HT turnover, as indicated by increased brain 5-hydroxyindolylacetic acid (SHIAA), also increase brain tryptophan (TAGLIAMONTE, AGLIAMONTE, P REZ-CRUET, STERN and GESSA, 1971). Also, food deprivation or immobilization cause. increases of both brain tryptophan and 5-HIAA in the rat (CURZON, JOSEPH and KNOW, 1972; PEREZ-CRUET, TACLIAMONTE, ACLIAMONTE and GESSA, 1972). Evidence of a mechanism for alteration of brain tryptophan specific to this amino acid would, teleologically at least, be consistent with a specific role for such an alteration in the regulation or modification of brain metabolism. Therefore, the effects of the above procedures upon the concentrations of tryptophan and other amino acids in the brain have been determined.