Central injection of neuropeptide Y modulates sexual behavior in male rats: interaction with GnRH and kisspeptin/neurokinin B/dynorphin.

AIMS

A number of studies have shown that neuropeptide Y (NPY) is considered to be one of the key regulators of hypothalamic-pituitary-gonadal (HPG) axis in the mammals. In addition, kisspeptin (encode by gene), neurokinin B (encode by gene) and dynorphin (encode by gene) (commonly known as KNDy secreting neurons) are a powerful upstream regulators of GnRH neuron in hypothalamus.

MATERIALS AND METHODS

The present study aims to investigate the effects of the intracerebroventricular (icv) injection of NPY and BIBP3226 (NPY receptor antagonist (NPYRA)) on the male sexual behavioral. Additionally, in order to see whether NPY signals can be relayed through the pathway of kisspeptin/neurokinin B/dynorphin, the gene expression of these peptides along with gene in the hypothalamus were measured.

RESULTS

The icv injection of NPY decreased the latencies and increase the frequencies of sexual parameters of the male rats in a significant way. In this line, NPYRA antagonized the stimulative effects of NPY. Moreover, data from real-time quantitative PCR indicated that injection of NPY significantly increased the gene expression of , and decrease the while treatment with NPYRA controlled the modulative effects of NPY on these gene expression.

CONCLUSIONS

In conclusion based on the results of this study, NPY can exert its impacts on the sexual behavior of male rats modulation of the KNDy secreting neurons as an interneural pathway to GnRH neurons.