促肾上腺皮质激素对慢痛大鼠脊髓生长抑素、c-fos表达及痛反应的影响

本研究应用免疫组化、原位杂交和痛级均数测定法,探讨鞘内注射促肾上腺皮质激素（ＡＣＴＨ）对甲醛引起大鼠脊髓内生长抑素（Ｓｏｍ）、ｃｆｏｓ表达及痛反应的影响。结果表明,足底注射甲醛可使大鼠脊髓内ｃｆｏｓ样免疫反应（ＦＬＩ）、Ｓｏｍ样免疫反应（ＳｏｍＬＩ）、ＦＬＩ／ＳｏｍＬＩ及前Ｓｏｍ原ｍＲＮＡ（ＰＰＳｍＲＮＡ）神经元数目显著增多以及痛级均数（ＰＩＲ）显著升高。而鞘内注射ＡＣＴＨ可显著抑制甲醛引起的大鼠脊髓内ＦＬＩ、ＳｏｍＬＩ、ＦＬＩ／ＳｏｍＬＩ及ＰＰＳｍＲＮＡ增多和ＰＩＲ升高效应。鞘内预先注射赛庚啶可阻断ＡＣＴＨ的抑制效应,而荷包牡丹碱、纳洛酮则无影响。结果提示,５羟色胺受体可能参与ＡＣＴＨ抑制甲醛引起的痛反应。

Effect of ACTH on the expression of somatostatin and c-fos in the spinal cord and formalin evoked pain response

In the present study, the effect of ACTH on the expression of somatostatin and c fos in the spinal cord and formalin induced pain responses in rats were studied using immunohistochemistry and in situ hybridization. The results showed that subcutaneous injection of formalin in the right hindpaw increased c fos like immunoreactivity (FLI), somatostatin like immunoreactivity (Som LI), Som LI/FLI and perprosomatostatin mRNA (PPS mRNA) in neurones of right spinal dorsal horn and significantly enhanced pain intensity rating. ACTH decreased the FLI, Som LI, Som LI/FLI and PPS mRNA levels of the spinal cord evoked by formalin. The decrease of c fos or Som level due to intrathecal injection of ACTH in rats with chronic pain was prevented by injection of cyproheptadine, but not by bicuculline and naloxone. The results indicate that the serotonin receptor may be involved in ACTH induced analgesia.