EFFECTS OF INGESTION OF A CARBOHYDRATE-FAT MEAL ON THE LEVELS AND SYNTHESIS OF 5-HYDROXYINDOLES IN VARIOUS REGIONS OF THE RAT CENTRAL NERVOUS SYSTEM |
| |
Authors: | J L Colmenares R J Wurtman J D Fernstrom |
| |
Institution: | Laboratory of Neuroendocrine Regulation, Department of Nutrition and Food Science, Massachusetts Institute of Technology, Cambridge, MA 02139, U.S.A. |
| |
Abstract: | —The concentrations of tryptophan, serotonin (5-HT), and 5-hydroxyindoleacetic acid (5-HIAA) in spinal cord and most brain regions increase 2 h after fasted rats begin to consume a carbohydrate-fat meal: indole levels rise in all portions of the brain studied, but the increase is not statistically significant in the hypothalamus and corpus striatum. The rate at which the brain synthesizes 5-hydroxy-indoles (as estimated in vivo by measuring 5-hydroxytryptophan accumulation following an injection of the decarboxylase inhibitor RO4-4602) is also accelerated in all of the regions in which the experimental diet elevates tryptophan, 5-HT and 5-HIAA levels. These observations indicate that the previously reported increase in brain 5-hydroxyindole levels following consumption of a protein-free meal reflects accelerated serotonin synthesis, and occurs within both the cell bodies and the terminals of serotonin-containing neurons. It is possible that diet-induced changes in neuronal serotonin levels influence the quantities of the neurotransmitter released into synapses, either spontaneously or in response to drugs. |
| |
Keywords: | |
|
|