Effects of different musical frequencies on ventromedial hypothalamus NPY and Ghrelin secretion in the rat.

It is known that music has physiological effects on the brain. The musical stimuli activate specific pathways in several brain areas associated with emotional behaviours, such as , hypothalamus and amygdala. Moreover, the hypothalamus is able to integrate orexigenic properties of a novel peptide, ghrelin, that induces food intake by way of neuropeptide Y (NPY). The aim of this research was to evaluate the effects of different musical frequencies (432 Hz and 440Hz) on immunohistochemical neuronal expression of these two peptides involved in regulating of food intake, in the rat. A significant immunohistochemical improvement of two peptides has been found in groups treated with musical frequency at 440 Hz compared with groups treated with frequency at 432Hz. Moreover the concentrations of ghrelin and NPY were higher in groups subjected to classical music in both frequencies than rock music. These results support the hypothesis that both different musical frequencies increase the expression of the NPY and peptide ghrelin , compared with controls group. It has been therefore hypothesized the existence of a correlation between the different musical frequencies and food-intake.