title: Age-related changes of serotonin and its metabolites content in the visual system of the rat.
abstract: Measurements have been taken of the serotonin and its metabolites (tryptophan, 5-hydroxytryptophan, 5-hydroxy-3-indolacetic acid and 5-hydroxytryptophol) in each structure of the geniculate and extrageniculate visual system of rats aged between 3 and 30 months. The concentration of tryptophan was the highest of all compounds studied. Its increase during ageing is statistically significant in the lateral geniculate and posterior thalamus. 5-HTP concentration was very low and in some cases not detectable. 5-HT concentrations and its principal metabolite, 5-HIAA, showed a different profile in each brain structure. The lateral geniculate and visual cortex showed statistically significant changes, but with opposite results. In the lateral geniculate the 5-HT and 5-HIAA concentrations were increased during the ageing period. However, in the visual cortex the 5-HT and 5-HIAA concentrations decreased in the same period. These age-related changes were not seen in the superior colliculus and posterior thalamus as in the 5-HT levels as in the 5-HIAA. 5-hydroxytryptophol was always found in low concentration. These results suggest age-related changes in the geniculate visual system.
mesh_terms: D000375:Aging / Q000378:metabolism*; D000818:Animals; D001921:Brain / Q000254:growth & development* / Q000378:metabolism; D005829:Geniculate Bodies / Q000254:growth & development; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000378:metabolism*; D013477:Superior Colliculi / Q000254:growth & development; D013788:Thalamus / Q000254:growth & development; D014793:Visual Cortex / Q000254:growth & development
chemical_list: D012701:Serotonin