猪脑苯甲二氮结合性抑制物的分离纯化及其镇痛活性

纯化猪脑苯甲二氮结合性抑制物 (DBI)并研究它在镇痛方面的生物学功能 .猪脑提取液经SephadexG 5 0分子筛层析、SP SepharoseFastFlow阳离子交换柱层析、SourceTM30SFPLC和RP HPLC分离得到DBI ,纯度达 93 5 % .经测定其相对分子质量 (Mr)为 980 8.3,pI为 7 2 .氨基酸组成及其序列检测结果表明 ,该蛋白由 86个氨基酸组成 ,与猪肠DBI的序列相同 ,而且N端都是乙酰化封闭的 .镇痛活性实验在SD雄性大鼠上进行 ,测量其对伤害性热和机械刺激反应的潜伏期作为指标 .将DBI注射到大鼠的侧脑室和脊髓蛛网膜下腔内 ,都产生明确的镇痛作用 ,在吗啡耐受的大鼠侧脑室注射DBI仍有镇痛作用 .无论在脊髓或脑水平 ,DBI对吗啡的抗伤害作用均无明显影响 .结果提示 ,中枢神经系统内 ,DBI在一定剂量内有明确的镇痛作用 ,对吗啡耐受的大鼠DBI仍有镇痛作用

Purification of Diazepan Binding Inhibitor from Pig Brain and Its Anti-nociceptive Effects

Diazepan binding inhibitor (DBI) has been purified from pig brain by sephadex G 50 chromatography, SP Sepharose Fast Flow ion exchange chromatography, SourceTM30S FPLC and RP HPLC. Pig brain DBI is composed of 86 amino acid residues with M r 9 803.5 determined by ESI MS and pI 7 2. The complete amino acid sequence of DBI was identical with DBI from pig upper intestine. Its N terminal is blocked through N acetylation at serine. The biological activity was evaluated with SD rats. The hindpaw withdrawal latency (HWL) of the rat to noxious thermal and mechanical stimulation regarded as indication increased significantly after intra cerebral ventricular administration or intrathecal administration of DBI in intact and morphine tolerant rats. There was no significantly influence of DBI on the anti nociceptive effect induced by morphine neither in the spinal cord nor in the brain. The results indicated that DBI played an anti nociceptive effect in the central nervous system, and there was no interaction between DBI and morphine in intact and morphine tolerant rats.