Expression of 5ª²HT2,4,5 receptor subtype mRNAs in rat spinal dorsal and ventral horns of different segments

    ZHOU Jing, LI Hui, LIU Xiangª²Yu, WANG Yaª²Yun, LI Yunª²Qing, WU Shengª²Xi

    1Medical Student of Grade 2000, 2Department of Anatomy and K. K. Leung Brain Research Center, Fourth Military Medical University, Xi¡¯an 710033, China

    ¡¾Abstract¡¿ AIM: To examine the expression of mRNAs encoding serotonin (5ª²HT) 5ª²HT2, 5ª²HT4 and 5ª²HT5 receptor subtypes within different segments of rat spinal cord. METHODS: Reverse transcriptaseª²polymerase chain reaction (RTª²PCR) technique was used. RESULTS: Strong expression of 5ª²HT2A receptor subtype mRNA was present in the ventral horn (VH) of cervical, thoracic and lumbar cord. 5ª²HT2C receptor mRNA was predominantly present in both dorsal horn (DH) and VH of the cervical, thoracic, lumbar and sacral segments of the spinal cord with higher expression level in the DH. The expression of 5ª²HT4 receptor mRNA in the DH and VH of different segments showed a gradually increasing pattern from cervical cord to sacral cord, with higher expression level in the DH and lower expression level in the VH of all the spinal cord segments. The 5ª²HT5A receptor mRNA was found at weak expression level in the spinal cord. No significant difference in its expression was observed between different segments or dorsal and ventral horns. The presence of 5ª²HT2B and 5ª²HT5B receptor mRNAs was not detected in the present study. CONCLUSION: Our data indicate a distinct expression pattern of 5ª²HT receptor subtypes in the spinal cord, suggesting their different physiological roles in the nociception and movement at the spinal level. ......