Abstract: Objective To study of the different expression of serotonin(5-HT) and serotonin receptor subtypes(5-HTRs) in T13~S1 spinal segments of chronic prostatitis rat models. Methods Sprague Dawley rats were randomly divided into control group，45，60 and 90 d model groups. Chronic prostatitis /chronic pelvic pain syndrome of rats were induced by autoimmune. The level of 5-HT was detected by Immunohistochemistry and the expression of 5-HTRs gene were detected by RT-PCR in T13~L2，L3~L4，L5~S1spinal segments in chronic prostatitis rats. Results The spontaneous pain behavior score of CP/CPPS rats was significantly higher compared with control group (P <0.05). The level of 5-HT in three spinal segments in all CP/CPPS model groups were decreased, 45d and 90d model group decreased significantly (P<0.05). The expression of 5-HTR2A，5-HTR5A showed a gradually increasing and 5-HT2C，5-HTR7 were increased at the first and then decreased in T13~L2 spinal segments (P<0.05). The expression of all receptors were decline after rising first in L3~L4 spinal segments (P<0.05). The expression of 5-HT2C，5-HTR5A showed a gradually increasing and 5-HTR2A，5-HTR7 were decline after rising first in L5~S1 spinal segments (P<0.05). Conclusion Our data indicated that there is a distinct expression pattern of 5-HT and 5-HTRs at different stages of CP/CPPS rat, suggesting that 5-HT system may involved in the central regulation mechanism of CP/CPPS，further study are needed for the specific mechanism.

Key words: serotonin, serotonin receptors, chronic prostatitis, spinal cord, rat