The Treatment Effect and Mechanism of Ketanserin on Inflammatory and Neuropathic Pain
|School||Fujian Normal University|
|Keywords||ketanserin 5-HT2A receptor CFA inflammatory pain neuropathic pain hyperalgesia neuropeptide Y|
The present study was conducted with behavioral and immunohistochemical techniques. The study was designed to test the hypothesis that the peripheral 5-HT2A receptor selective antagonist was involved in CFA-induced inflammatory pain and L5 spinal nerve ligation induced neuropathic pain.The hind paw of rats were injected with CFA produce chronic inflammatoy pain,24 hours later ketanserin were injected on the ipsilateral side of the paw, per 24 hours once and sustain 3 days, the results showed that ketanserin can inhibit CFA induced thermal hyperalgesia and mechanical hyperalgesia, but cannot completely reversed. However, the effects of ketanserin was enhanced with the increasement of the dose. when the dose get 80μg, the analgesia effect is basically close to normal level. But when ketanserin was injected subcutaneously, it is no effect on inflammatory pain. So, the 5-HT2A receptor plays a role in peripheral analgesia in chronic inflammatory pain.Immunohistochemical study showed that the expression of NPY in the dorsal horn of spinal cord was upregulated in CFA induced chronic inflammatory pain rats, but the effect was changed while administration of ketanserin. However, there is no change of NPY expression when ketanserin was injected into the normal rats paw. This indcated that NPY is mainly modulate pain through the central nervous system.L5 spinal nerve ligation model is a widely used neuropathic pain model, when ketanserin was injected in cervical part of rat subcutaneous of rat, it can inhibit neuropathic pain induced mechanical hyperalgesia. The results showd that the effect of 5-HT2A receptor plays a role in central analgesia in neuropathic pain.The study also showed that 5-HT is involved of the development of inflammatory and neuropathic pain, and this action was conducted mainly through 5-HT2A receptor.