刺乌头碱氢溴酸盐的药理作用研究

用热板,扭体反应(小鼠)和光热甩尾法测试表明,刺乌头碱均有镇痛作用。小鼠多次注射刺乌头碱后,再给予烯丙吗啡,不出现跳跃反应。对依赖吗啡大鼠或猴停药后的戒断症状无替代取消作用。猴长期注射刺乌头碱后停药不出现戒断综合症,表明刺乌头碱是一种不成瘾的止痛剂。刺乌头碱有较强的局部麻醉作用。对三联疫苗发热小鼠有解热作用。对大鼠甲醛性“关节炎”有消炎作用。     

乌头属和翠雀花属植物中的刺乌头碱和 N-去乙酰基刺乌头碱对心脏的作用

乌头属植物根的制剂在中国、日本广泛用于止痛和抗风湿治疗,这是由于该类植物所含二萜类生物碱的作用。乌头属及翠雀花属植物中生物碱含量因品种不同而异。在具有抗感受伤害和抗炎作用的生物碱中,从高乌头 Aconitum sinomontanum Nakai 中分离到的刺乌头碱(LA)是一个对河豚毒素敏感、电压依赖性钠通道阻滞剂,它是作用于中枢     

TLC—HPLC法测定小活络丸内中乌头碱,次乌头碱和乌头碱的含量

采用ＴＬＣ－ＨＰＬＣ法测定小活络丸内中乌头碱、次乌头碱和乌头碱的含量，在硅胶Ｇ薄层板上以石油醚－正己烷－醋酸乙酯－无水乙醇－浓氨水（１：２：５：５：０．５）为展开剂，分离提取酯型三，用Ｒｅｓｏｌｖｅ Ｓｐｈｅｒｉｃａｌ Ｓｉｌｉｃａ柱，以无水乙醇－０．４％醋酸铵水溶液（９７：３）为流动相进行测定，检测波长２３１ｎｍ，平均回收率：８３．２％（中乌头碱）、９２．１（次乌头碱）、８４．１％（乌头碱）。     

伍用刺乌头碱对3-乙酰乌头碱毒性及镇痛作用的影响

刺乌头碱(0.5mg·kg~(-1))对3-乙酰乌头碱(0.07mg·kg~(-1))诱发大鼠心律失常有显著的对抗作用.二者伍用(剂量LA:AA=7:1)对镇痛作用无明显影响.但刺乌头碱可显著提高3-乙酰乌头碱小鼠的LD_(50),从而提高其治疗指数.扩大其安全范围。     

HPLC测定制川乌中的乌头碱、次乌头碱和新乌头碱

目的 建立RP-HPLC测定制川乌中乌头碱、次乌头碱和新乌头碱含量的方法.方法 采用Zorbax Eclipse XDB-C8色谱柱(200 mm ×4.6 mm,5 μm);以20 mmol·L-1三乙胺溶液(磷酸调pH3)-甲醇(95:5)为流动相梯度洗脱;检测波长235nm;柱温30 ℃;流速1.0 mL·min-1.结果 三种生物碱得到有效分离,回归方程分别为:Y乌头碱=1.257×104X+0.222(r=0.9999)、Y次乌头碱=1.302×104X+0.293(r=0.9997)、Y新乌头碱=1.295×104X-0.119(r=0.9999);线性范围为:0.5～20.0μg·mL-1;平均加样回收率分别为98.42%、97.51%、98.33%;RSD分别为1.05%、1.07%、1.05%(n=6).结论 所建方法对制川乌中生物碱的含量控制具参考意义.     

高效液相色谱法测定草乌叶中新乌头碱、乌头碱和次乌头碱

目的 建立以高效液相色谱法同时测定蒙药草鸟叶中新乌头碱、乌头碱、次乌头碱的方法.方法 Extend-C18柱(250 mm×4.6 mm,5μm),流动相为甲醇-0.3 mol/L三乙胺(65:35),体积流量为0.8 mL/min,检测波长为235 nm,柱温为35℃.结果 经过方法学考察,本测定方法具有一定的专属性、准确性、重现性和可行性,新乌头碱、乌头碱、次乌头碱分别在1～5、0.35～1.75、0.5～2.5 μg呈良好的线性关系,平均加样回收率分别为98.43%、98.98%、98.82%,RSD分别为1.38%、0.89%、1.03%.结论 本方法简便、准确、分离效果好、线性范围宽、灵敏度高,可用于本品的质量控制.     

TLC一HPLC法测定小活络丸内中乌头碱、次乌头碱和乌头碱的含量

采用ＴＬＣ－ＨＰＬＣ法测定小活络丸内中乌头碱、次乌头碱和乌头碱的含量。在硅胶Ｇ薄层板上以石油醚（６０～９０℃）－正己烷－醋酸乙酯－无水乙醇－浓氨水（１：２：５：５：０．５）为展开剂，分离提取酯型生物碱，用Ｒｅｓｏｌｖｅ　Ｓｐｈｅｒｉｃａｌ　Ｓｉｌｉｃａ柱（５μｍ，１５０ｍｍ×３．９ｍｍ），以无水乙醇－０．４％醋酸铵水溶液（９７：３）为流动相进行测定，检测波长２３１ｎｍ，平均回收率：８３．２％（中乌头碱）、９２．１（次乌头碱）、８４．１％（乌头碱）。     

Roles of periaqueductal gray and nucleus raphe magnus on analgesia induced by lappaconitine, N-deacetyllappaconitine and morphine

In the rat tail flick test, ip LA 6 mg/kg, icv DLA 60 micrograms and icv or with morphine 5 micrograms exhibited significant analgesia. But with either LA 40 micrograms or DLA 60 micrograms was inactive. Naloxone (4 micrograms icv) which antagonized morphine analgesia failed to alter the analgesia induced by LA and DLA. Microinjection of DLA 20 micrograms or morphine 5 micrograms into the periaqueductal gray (PAG) or nucleus raphe magnus (NRM) produced markedly analgesic activity. The effects of electrolytic and kainic acid (0.8 micrograms) lesions of the PAG and NRM on the analgesia elicited in the rat from ip LA, icv DLA and morphine were also evaluated. No change in baseline tail flick latency was observed following lesions of the PAG and NRM. But lesions of the PAG and NRM significantly attenuated the analgesia mediated by LA, DLA and morphine. These results suggest that supraspinal sites, especially the PAG and NRM, are involved in the analgesic action induced by LA, DLA and morphine.     

Influence of omega-conotoxin on morphine analgesia and withdrawal syndrome in rats.

The effect of omega-conotoxin on opiate analgesia and withdrawal syndrome was investigated in rats. omega-Conotoxin given i.c.v. and i.p. caused weak analgesia in the tail-flick test. When the toxin (20 ng/rat) was given i.c.v. immediately before morphine (1.5 micrograms/rat i.c.v.) the resultant analgesic effect was additive. In contrast, the analgesia elicited by morphine (3 micrograms/rat i.c.v.) was greatly reduced after 24-h pretreatment with the toxin (20 ng/rat i.c.v.). The systemic administration of the toxin (10 micrograms/kg i.p.) did not affect morphine analgesia whether omega-conotoxin was coadministered with morphine (2.5 mg/kg i.p.) or was given 24 h before the opiate (5 mg/kg i.p.). omega-Conotoxin i.c.v. injected in morphine-dependent rats 15 min before naloxone challenge significantly attenuated the abstinence syndrome. On the contrary systemic administration of omega-conotoxin failed to suppress the morphine withdrawal syndrome. The present results suggest that omega-conotoxin affects both acute and chronic effects of morphine.     

D-Ala2,F5Phe4-dynorphin amide, an opiate with analgesic and toxic properties.

A novel analog of dynorphin (1-13), D-Ala2,F5Phe4-dynorphin amide, was prepared and its pharmacological spectrum of activity was investigated. In a hot plate test on Swiss Webster and C57Bl mice, a 20 micrograms intracerebroventricular (icv) dose of the analog produced analgesia, which was greater in potency and duration than the parent dynorphin. This action of D-Ala2,F5Phe4-dynorphin amide was antagonized by the opiate receptor antagonist naloxone (2 mg/kg ip), administered either before or after the peptide. In addition to its analgesic action in mice, D-Ala2,F5Phe4-dynorphin amide produced a Straub tail and a catatonic-like state, both of which were also attenuated by naloxone. On the electrically-stimulated mouse vas deferens preparation, in vitro, D-Ala2,F5Phe4-dynorphin amide inhibited contractile activity and had an IC50 of 108.2 +/- 34.7 nM (SEM), about 4-fold weaker than that of dynorphin. This action was also attenuated by naloxone. An icv dose of 150 micrograms of D-Ala2,F5Phe4-dynorphin amide in mice, and a cumulative series of icv doses up to 2600 micrograms in anesthetized rats, failed to produce a lethal effect. No pathological changes were observed in mouse liver and kidney at 24 h after a 50 mg/kg dose of the peptide analog. In rats anesthetized with diallylbarbital (70 mg/kg ip) and urethane (280 mg/kg ip), D-Ala2,F5Phe4-dynorphin amide did not modify blood pressure, heart rate and respiratory rate. However, when mice were injected peripherally with single doses of D-Ala2,F5Phe4-dynorphin amide, convulsive episodes were produced, and lethal effects were observed with an LD50 of 60.0 mg/kg (95% confidence limits: 49.7-70.2 mg/kg) at 48 h. This action of D-Ala2,F5Phe4-dynorphin amide was not attenuated by naloxone (2.0 mg/kg, ip). Although analgesic and behavioral effects of D-Ala2,F5Phe4-dynorphin amide (e.g. Straub tail and catatonic-like state) are opiate-like, the lethal effect may be the consequence of actions of the peptide on non-opiate systems, Thus, the novel fluorinated dynorphin analog, D-Ala2,F5Phe4-dynorphin amide, may be a useful chemical tool for the study of opiate systems and their occasionally unanticipated biological or toxic actions.     

Effect of chronic and acute administration of fluoxetine and its additive effect with morphine on the behavioural response in the formalin test in rats

Serotonergic systems are involved in the central regulation of nociceptive sensitivity. Fluoxetine, a selective inhibitor of the reuptake of serotonin (5-hydroxytryptamine, 5-HT), was administered orally (0.16, 0.32, 0.8 mg kg(-1) daily for 7 days), intraperitoneally (0.04, 0.08, 0.16 mg kg(-1) day(-1) for 7 days and a single dose of 0.32 mg kg(-1)) and intracerebroventricularly (10 microg/rat) to rats and nociceptive sensitivity was evaluated using the formalin test (50 microL of 2.5% formalin injected subcutaneously). The effect of fluoxetine was also studied in the presence of 5,7-dihydroxytryptamine creatinine sulfate (5,7-DHT) and after co-administration with morphine. Oral (0.8 mg kg(-1)), intraperitoneal (0.16 and 0.32 mg kg(-1)) and intracerebroventricular (10 microg/rat) fluoxetine induced antinociception in the late phase of the formalin test. Furthermore, intrathecal administration of 5-HT (100 microg/rat) induced an analgesic effect. The analgesic effect of fluoxetine (0.16 and 0.32 mg kg(-1), i.p.) and 5-HT (100 microg/rat, i.t.) was abolished by pre-treatment with 5,7-DHT (100 microg/rat, i.t.). In addition, the analgesic effect of 5-HT (100 microg/rat, i.t.) was decreased by pre-treatment with naloxone (2 mg kg(-1), i.p.). Morphine (5 mg kg(-1), i.p.) induced analgesia that was increased by fluoxetine (0.32 mg kg(-1), i.p.). These results suggest that fluoxetine has an antinociceptive effect in tonic inflammatory pain through functional alteration of the serotonergic system and also potentiates the analgesic effect of morphine.     

Involvement of serotoninergic mechanism in analgesia by castration and flutamide, a testosterone antagonist, in the rat formalin test

Several studies have suggested that testosterone has a role in nociception. Recently, we have shown that castration and flutamide, a testosterone antagonist, induce analgesia in the late phase of formalin test, which is related to increase of 5-HT levels in the dorsal horn of the lumbar spinal cord. The aim of the present study was to investigate the effect of fluoxetine, a selective serotonin reuptake inhibitor, on castration and flutamide-induced analgesia in order to further explore the role of 5-HT systems in such analgesia. Four weeks after castration, there was an analgesia in the late phase of formalin test, and this was potentiated by acute (0.32 mg kg(-1) ip) treatment of fluoxetine. Furthermore, coadministration of fluoxetine (0.32 mg kg(-1) ip) and flutamide (10 mg kg(-1) ip) produced more antinociceptive effect than those animals receiving fluoxetine and flutamide alone. The analgesic effect of fluoxetine (0.32 mg kg(-1) ip) and flutamide (10 mg kg(-1) ip) was abolished by pretreatment with 5,7-DHT (100 microg/rat it) and naloxone (2 mg kg(-1) ip). In summary, our data suggest that fluoxetine and flutamide have antinociceptive effects in tonic inflammatory pain through functional alteration of serotonergic systems, and their effects are potentiated by coadministration. The possible role of opioidergic system in their antinociceptive effect cannot be neglected.     

利血平与优降宁对动物痛阈和吗啡镇痛作用影响因素探讨

采用三种测痛方法,观察了利血平、优降宁对小鼠、大鼠正常痛阈和吗啡镇痛作用的影响,结果表明:ip利血平2 mg/kg,优降宁100 mg/kg均能明显抑制小鼠扭体反应;ip利血平1 mg/kg能明显提高小鼠热板反应时间,但ip优降宁75 mg/kg无明显影响;ip利血平6 mg/kg,优降宁75 mg/kg对大鼠甩尾反应时间均无明显影响;利血平(小鼠0.5～1.0 mg/kg,大鼠2 mg/kg ip)能明显对抗吗啡镇痛作用;优降宁(小鼠35 mg/kg,大鼠50 mg/kg ip)能明显增强吗啡镇痛作用,并能“逆转”利血平对抗吗啡镇痛作用。其“逆转”作用的强弱取决于利血平、优降宁给药的先后次序。     

利血平与优降宁对动物痛阈和吗啡镇痛作用影响因素探讨

采用三种测痛方法,观察了利血平、优降宁对小鼠、大鼠正常痛阈和吗啡镇痛作用的影响,结果表明:ip利血平2 mg/kg,优降宁100 mg/kg均能明显抑制小鼠扭体反应;ip利血平1 mg/kg能明显提高小鼠热板反应时间,但ip优降宁75 mg/kg无明显影响;ip利血平6 mg/kg,优降宁75 mg/kg对大鼠甩尾反应时间均无明显影响;利血平(小鼠0.5～1.0 mg/kg,大鼠2 mg/kg ip)能明显对抗吗啡镇痛作用;优降宁(小鼠35 mg/kg,大鼠50 mg/kg ip)能明显增强吗啡镇痛作用,并能“逆转”利血平对抗吗啡镇痛作用。其“逆转”作用的强弱取决于利血平、优降宁给药的先后次序。     

滇西嘟拉碱甲的镇痛和身体依赖性研究

用扭体法、热板法、光热-甩尾法和甲醛致痛法证实Bul有明显镇痛作用。连续给药9 d,镇痛作用无耐受现象。小鼠跳跃反应试验阴性;Bul对吗啡依赖大鼠或猴的戒断症状,均无替代作用。Bul的镇痛作用不能被纳络酮翻转;利血平可取消Bul的镇痛作用,补充5-HT或5-HTP能翻转利血平取消Bul的镇痛作用。