The Central Nervous System 5-HT2B Receptor As a Potential Target for Regulating Ejaculatory Behaviour in Male Rats

Objective: To investigate whether 5-HT and the newest member of the 5-HT2B receptor family 5-HT2B receptor in the central system, have a key role in ejaculation regulation by constructing an animal model of primary premature ejaculation. Materials and Methods: A rat model of primary premature ejaculation was constructed, and the differential expression profiles of 5-HT2B and 5-HT in the central system were established. Results: Compared with the "normal ejaculation " and "delayed ejaculation" rats’ group, the "rapid ejaculation" rats’ group had shorter mount latency and intromission latency, and fewer mount frequency and intromission frequency before the first ejaculatory. In the "rapid ejaculation", "normal ejaculation" and "delayed ejaculation" groups, there were significant differences in the levels of 5-HT in the hippocampus and raphe nucleus of rats. The 5-HT levels in the hippocampus and raphe nucleus of rats in the "rapid ejaculation" group were significantly lower than those in the "normal ejaculation" and "delayed ejaculation" groups. In the hippocampus and raphe nucleus of the central system of rats, the concentration of 5-HT was significantly lower than that of the "normal" and "delayed" groups. The expression levels of 5-HT2B receptor proteins were significantly higher in the "rapid ejaculation" group than in the "normal ejaculation" and "delayed ejaculation" groups. Conclusion: We found that rats with different ejaculatory behaviors have a different 5-HT2B expression in the central nervous system. The expression of 5-HT2B receptors in different brain regions of the CNS is closely related to the different sexual behaviors of rats, suggesting that it may have a key role in the regulation of ejaculation in the central system of rats.