Antinociceptive efficacy of preemptive intrathecal administration of CRH in rats / 第三军医大学学报

ABSTRACT

Objective To investigate whether preemptive intrathecal administration of CRH has an antinociceptive efficacy on inflammatory pain model rats. Methods The antinociceptive efficacy of preemptive intrathecal administration of CRH was evaluated by the flinch-licking time and the tail flicking latency in formalin-subjected pain model rats. The c-fos gene expression in spinal cord dorsal horn was analyzed by immunohistochemical technique and computer image technique. Results Comparing with NS control group, preemptive intrathecal administration of 0.5 ?g CRH could markedly inhibit the phase Ⅱpain reaction and meanwhile decrease c-fos gene expression by 25.02% in the superficial lamella of spinal cord dorsal horn of the model rats. The antinociceptive efficacy could be counteracted by preemptive intraperitoneal injection of CP-154526 (the specific antibody of CRHR1, 10 mg/kg). Conclusion CRH could significantly inhibit pain reaction and spinal cord c-fos gene expression, and thereby preemptive intrathecal administration of CRH will contribute to the antinociceptive efficacy because of its potency of inhibiting hyperalgesia.