Effect of corticotropin on formalin-evoked c-fos expression of spinal cord and receptors analysis in rat

AIM: To study the effect of corticotropin (Cor) on c-fos expression induced by formalin in spinal cord of rat and the role of receptors. METHODS: Using immunohistochemistry and adrenalectomy. RESULTS: Cor inhibited the formalin-evoked c-fos expression in rat spinal cord in a dose-dependent manner. No obvious effect was seen by i.p. Cor 10 U.kg-1, but 25 U.kg-1 reduced the evoked c-fos expression, that was blocked by phentolamine, naloxone, or verapamil, but not much changed by adrenalectomy. CONCLUSION: The formalin-evoked c-fos expression of rat spinal cord was suppressed by Cor through the alpha-adrenergic receptors, opiate receptors and calcium, but no relation to adrenal glands.