Influence of prenatal noise and music on the 5-hydroxytryptamine synthesis and the tryptophan hydroxylase expression in the raphe nuclei of young rats

During the prenatal period, development of individual is influenced by the environmental factors. In mammals, 5-hydroxytryptamine (5-HT) is a central neurotransmitter that regulates behavioral functions in the vertebrate brain. Tryptophan hydroxylase (TPH) is a rate-limiting enzyme in the 5-HT synthesis. Various stresses are known to modulate the 5-HT synthesis and the TPH expression. In the present study, the influence of prenatal noise and music application on the 5-HT synthesis and the TPH expression in the dorsal and median raphe of young rats was investigated. Prenatal noise application increased the 5-HT synthesis and the TPH expression in the dorsal and median raphe nuclei of offspring. Prenatal music application, in contrast, decreased the 5-HT synthesis and the TPH expression in the dorsal and median raphe nuclei of offspring. The present study suggests that prenatal stimuli including noise and music may affect the emotional state of offspring.