The Influence Of 8-OH-DPAT And Nimodipine Administrated Subarachnoidly On The Inflammation Pain Of The Rat

Objective:To evaluate the effects of the the 5-HT1A agonist(±)-8- hydroxy-2- (di-n-propyl- amino) tetralin(8-OH-DPAT)and the L-type calcium channel blocker Nimodipine admini- strated subarachnoidly on the inflammation pain in rat spinal cord and the possible role.Method:After intrathecal catheter being implanted,104 adult male SD rats were randomly divided into 13 groups of eight each.. After the injection of the carrageenan in the right hind paw, the normal saline and/or different drugs were administrated intrathecally individually. Then to investigated the mechanism threshold of the pain bye the VonFrey Monofilaments and the thermal latency at the time of the point of the 3 and 15 hours of the inflammation pain.Results:After the injection of the carrageenan in the right hind paw, the mechanism threshold and the thermal latency were reduced at the time of the point of the 3 and 15 hours. The 8-OH-DPAT administrated intrathecally had analgesia at the time of the first phase(p<0.05),and the role depended on the dosage of 8-OH-DPAT ,but 8-OH-DPAT had not analgesia at the late phase(p>0.05).The small dosage of L-type calcium channel blocker Nimodipine could not influence the mechanism threshold and the thermal latency at the two phase of the inflammation pain,but it could enhance the analgesia of 8-OH-DPAT at the first phase of the inflammation and it depended on the dosage.Conclusions: (1) The 5-HT1A agonist 8-OH-DPAT had analgesia at the first phase of the inflame- mation pain in rat. (2) The L-type calcium channel blocker Nimodipine administrated intrathecally individually could not reduce the inflammation pain but it could enhance the analgesia of 8-OH-DPAT.