5-HT_(1A)受体激动剂乌拉地尔对吗啡依赖大鼠戒断反应的抑制作用

目的··：观察５－ＨＴ１Ａ受体激动剂乌拉地尔（ｕｒａｐｉｄｉｌ）和８－ＯＨ－ＤＰＡＴ及阿片μ受体激动剂美沙酮（ｍｅｔｈａｄｏｎｅ）对吗啡戒断反应的影响。方法··：采用吗啡依赖大鼠模型侧脑室注射上述药物,并用腹腔注射纳洛酮诱发戒断反应,记录戒断症状。结果··：侧脑室注射乌拉地尔可明显抑制纳洛酮诱发的吗啡躯体戒断反应,并呈量效关系。乌拉地尔抑制吗啡戒断反应的作用与８－ＯＨ－ＤＰＡＴ的作用一致。此效应与美沙酮的作用相比也基本相同。结论··：乌拉地尔通过激活５－ＨＴ１Ａ受体可以抑制吗啡戒断反应。     

胍丁胺对阿片受体环腺苷—磷酸信号转导系统代偿适应的影响

目的:观察胍丁胺对阿片类所致脱敏和物质依赖的作用。方法:分别用放射配体结合实验和放免法测定γ-[~(35)S]-三磷鸟苷([~(35)S]GTTP)结合量和环腺苷一磷酸(cAMP)浓度。结果:在经阿片类药物预处理的NG108-15细胞实验中,胍丁胺使阿片类药物刺激[~(35)S]GTTP结合作用增强35％;使阿片类药物对cAMP抑制作用增强114.3％;使纳洛酮引起的吗啡物质依赖细胞cAMP超射幅度和对照组相比减小214.9％。胍丁胺的上述作用均可被咪唑克生浓度依赖性阻断。结论:胍丁胺通过激活咪唑啉受体阻止cAMP信号转导通路代偿适应过程的形成。     

胍丁胺对阿片受体环腺苷—磷酸信号转导系统代偿适应的影响

观察胍丁胺对阿片类所致脱敏和物质依赖的作用。方法：分别用放射配体结合实验和放免法测定γ－「３５Ｓ」－三磷鸟苷结合量和环腺苷一磷酸浓度。结果：在陛阿片类药物预处理的ＮＧ１０８－１５细胞实验中,胍丁胺使阿片类药物刺激「＾３５Ｓ」ＧＴＴＰ结合作用的增强３５％;合阿片类药物对ｃＡＭＰ抑制作用增强１１４．３％,使纳洛酮引起的吗啡物质依赖细胞ｃＡＭＰ超射幅度和对照组减小２１４．９％。     

胍丁胺调节阿片功能的分子和神经生物学机制

胍丁胺是一种内源性生物活性物质,由左旋精氨酸在左旋精氨酸脱羧酶作用下脱羧生成。我们的前期研究发现不管是内源性还是外源性胍丁胺都具有明确的阿片功能调节作用,表现为镇痛、增强吗啡镇痛、抑制吗啡耐受,躯体依赖和精神依赖。近年来,在这些工作的基础上,我们研究了胍丁胺调节阿片功能的分子和神经生物学机制。提出了胍丁胺调节阿片功能可能和激活咪唑啉受体有关这一假说。为了证明这一假说的客观性,本实验室首次建立了IRAS-Cho细胞稳定表达系统,通过观察IRAS的亚细胞定位、配体结合特性、生物学功能和信号转等证明了由美国科学家克隆的IRAS就是野生型I1咪唑啉受体。在此细胞模型上,我们首次证明胍丁胺调节阿片功能与激活I1咪唑啉受体相关。为了在神经元上,特别是在整体行为学实验模型上证明上述发现的存在,本实验室用RNA干涉技术在大鼠原代培养海马神经元和大鼠摇体实验模型上进一步证明胍丁胺调节阿片功能与激活I1咪唑啉受体相关。     

吗啡长期给药后大鼠脑内MAO—B活性及咪唑啉受体的下调

目的:探讨吗啡长期给药处理后大鼠不同脑区MAO-B活性及咪唑啉受体含量的变化。方法:用[~3H]咪唑克生配体结合试验测定咪唑啉受体含量,用高效液相色谱法测定MAO-B活性。结果:咪唑克生和吗啡能剂量依赖性地抑制大鼠脑匀浆MAO-B活性。咪唑啉受体的内源性配体胍丁胺既不影响MAO-B活性,也不影响咪唑克生及吗啡对MAO-B活性的抑制作用。吗啡连续给药16d后大鼠大脑、海马、丘脑、纹状体及小脑内MAO-B活性均显著下调(P<0.01)。纳洛酮及咪唑克生单次给药对吗啡依赖大鼠上述脑区MAO-B活性均没有进一步影响;胍丁胺伴随吗啡给药后能显著抑制吗啡降低MAO-B活性的作用。吗啡连续给药后大鼠皮层和小脑咪唑啉受体数量减少而亲和力上调(P<0.05)或P<0.01)。结论:MAO-B活性与吗啡依赖大鼠发生戒断综合征相关,但与胍丁胺对吗啡镇痛作用的影响无关;胍丁胺对吗啡药理作用的影响与其激活咪唑啉受体有关。     

双向阿片功能调节剂：胍丁胺

近年研究表明某些药物尽管不能与阿片受体发生相互作用，但能对阿片药理作用产生重要的调节．特别是有些药物能对阿片功能产生双向调节作用，即增强阿片镇痛，对抗阿片耐受和躯体依赖．我们将这些不与阿片受体发生作用，但具有双向调节阿片功能的药物称之为双向阿片功能调节剂(biphasic opioid function modulator，BOFM)．基于我们的研究工作，可以认定胍丁胺就是一个典型的双向阿片功能调节剂．胍丁胺本身有弱的镇痛作用，它能增强吗啡镇痛，对抗吗啡耐受和依赖：胍丁胺产生上述作用的主要机制与抑制阿片长期作用下在阿片受体信号转导系统产生的代偿性适应过程相关．     

利用RNA干扰技术研究I1咪唑啉受体在阿片依赖中的作用

目的：我们和国外实验室先后研究发现胍丁胺对阿片依赖具有调节作用，其作用可能与I1咪唑啉受体（I1-imidazoline receptor，I1R）有关。但由于没有特异性咪唑啉受体拮抗剂且胍丁胺的作用靶点较多，到目前为止，I1R是否为胍丁胺抗阿片依赖的主要作用靶点尚不能完全确定。因此，本文旨在利用RNA干扰技术确定I1R是否介导胍丁按对阿片依赖的调节作用。方法：利用RNA干扰技术下调细胞内源性I1R的表达，     

Effects of agmatine on tolerance to and substance dependence on morphine in mice

目的：观察胍丁胺对吗啡所致耐受和依赖的作用．方法：分别在小鼠耐受和跳跃实验中观察胍丁胺抑制吗啡所致耐受和物质依赖的作用．结果：胍丁胺０１２５－２５ｍｇ·ｋｇ－１剂量依赖性地阻止小鼠对吗啡耐受．用吗啡预处理小鼠使吗啡镇痛ＥＤ５０（２０１,１４４－２８０ｍｇ·ｋｇ－１）与盐水组相比（６３,５１－７８ｍｇ·ｋｇ－１）增加３倍以上．用胍丁胺和吗啡共同预处理小鼠则使吗啡丧失引起耐受的能力．胍丁胺（２５－１０ｍｇ·ｋｇ－１）剂量依赖性地抑制由纳洛酮引起的吗啡依赖小鼠之戒断跳跃和体重减轻．用胍丁胺和吗啡共同处理小鼠使引起小鼠之戒断跳跃所需纳洛酮ＥＤ５０（２１４,１８４－２４ｍｇ·ｋｇ－１）较吗啡处理组（２５,２１－２８ｍｇ·ｋｇ－１）增大８倍．胍丁胺的上述作用均被咪唑克生所阻断．结论：胍丁胺通过激活咪唑啉受体而阻止小鼠对吗啡耐受和依赖．     

胍丁胺对吗啡长期处理引起的NMDA受体蛋白表达改变的影响

目的:观察胍丁胺对吗啡长期处理引起的NMDA受体蛋白改变的影响。方法:采用吗啡递增给药制备大鼠慢性依赖模型,并观察依赖状态下大鼠海马和伏隔核NMDA受体NR1和NR2B亚基蛋白表达量的变化,以及胍丁胺对吗啡作用的影响。结果:与对照组相比,吗啡慢性处理大鼠在纳洛酮催促下能出现典型的戒断综合征,提示依赖模型建立成功。用免疫印记(Western blotting)技术发现,海马部位的NR2B亚基明显下调,而NR1亚基未见显著性变化;吗啡慢性处理不引起伏隔核NR2B亚基的明显变化,但NR1亚基却显著上调。胍丁胺与吗啡伴随给药能逆转吗啡对两脑区NMDA受体蛋白表达的调节作用。结论:胍丁胺调节阿片依赖可能与其逆转吗啡对NMDA受体亚基数量和构成的调节有关。     

华痛愈对吗啡依赖大鼠的脱毒疗效及实验止痛作用

目的··：研究中药华痛愈对吗啡依赖大鼠戒断综合征的疗效及对小鼠的镇痛作用。方法··：先建立吗啡依赖大鼠模型,然后给予大鼠腹腔注射纳洛酮催瘾,观察经不同药物处理后动物的戒断症状反应。镇痛试验采用热板法和扭体法。药物中阿片类成分及东莨菪碱的测定采用薄层层析法。结果··：用药组的戒断综合积分、体重减轻情况及其对热刺激的痛阈值和出现的扭体反应次数与ＮＳ组比较,差异均有显著性意义（Ｐ＜０．０１）。结论··：华痛愈是一种非阿片类、非东莨菪碱中药制剂,能明显缓解实验性阿片类药物依赖的戒断综合征,并可能对缓解戒断综合征中的疼痛有一定帮助,是治疗阿片类药物依赖的有效药物。     

Relationships between agmatine anti-abstinence syndrom and its inhibition on down-regulation of hippocampal neurogenesis in morphine-dependent rats

Agmatine derived from arginine is recently considered as a neurotransmitter and/or neuromodulator that potentiates morphine analgesia and inhibits the symptoms of naloxone-precipitated withdrawal in morphine dependent rats.The exact mechanisms of the inhibition of agmatine are not completely known.Recently,more and more results indicate that down-regulation of hippocampal neurogenesis is involved in opioid physical dependence.Therefore,the present study was undertaken to investigate the relationships between agmatine anti-abstinent syndrome and its inhibition on down-regulation of hippocampal neurogenesis in morphine dependent rats,and the possible mechanisms.We found that the chronic pretreatment with morphine induced a classical naloxone-precipitated abstinent syndrome and a decrease in neurogenesis by 23% in the adult rat hippocampal granule cell layer compared with those of saline control.Co-administration of agmatine with morphine was able to inhibit significantly the abstinent syndrome and the decrease in neurogenesis in the adult rat hippocampal granule cell layer at same time.Furthermore,agmatine inhibited the decreased hippocampal expression of brain-derived neurotrophic factor and phosphorylated CREB,in response to chronic pretreatment with morphine.On the other hand,pretreatment with agmatine in vitro significantly increased the proliferation of cultured hippocampal progenitor cells.All these results suggest that agmatine could inhibit morphine-induced physical dependence by up-regulation of the expression of brain-derived neurotrophic factor and cell proliferation in the adult rat hippocampus.Although agmatine is thought to ameliorate morphine dependence in multiple ways,the neurotrophic pathway may be one of the most important routes.     

纳洛肼及14-羟基双氢吗啡肼与阿片受点结合的可逆性

用纳洛肼(NZI,1×10^-5M)或14-羟基双氢吗啡肼(HZI,1×10^-6)与大鼠脑匀浆P₂膜制备保温后,以Tris缓冲液反复洗涤,阿片受点可完全恢复与[³H]双氢吗啡([³H]DHM)的结合能力。在离体豚鼠回肠纵肌(GPI)试验中,HZI对电刺激收缩的抑制及NZI对吗啡(Mor)抑制作用的对抗亦皆可被洗掉,此外HZI对收缩的抑制还可被纳洛酮(Nal)所逆转,说明它们与阿片受点的结合都是可逆的。HZI镇痛作用ED₅₀为1.3 mg/kg(小鼠热板法SC),略强于Mor(3 mg/kg),持续时间与Mor相似。NZI对Mor镇痛的对抗可持续十余小时。     

咪唑克生对吗啡镇痛、耐受和身体依赖的影响

目的:观察咪唑克生对吗啡镇痛及吗啡所致耐受和躯体依赖的影响.方法:采用小鼠醋酸扭体实验和55℃热板实验观察咪唑克生对基础痛阈及吗啡镇痛作用的影响;采用小鼠热辐射甩尾实验和小鼠55℃热板实验观察咪唑克生对吗啡耐受形成过程的影响;采用大鼠、小鼠身体依赖模型观察咪唑克生对吗啡所致身体依赖的影响.结果:咪唑克生(3-9mg/kg)能显著降低小鼠基础痛阈,抑制吗啡镇痛;加重吗啡所致耐受;诱发大、小鼠发生戒断综合征.结论:咪唑啉受体参与痛阈形成;咪唑克生能抑制吗啡镇痛,加重吗啡所致耐受;并诱发吗啡依赖性动物发生戒断综合征.     

Inhibition of agmatine on psychological dependence induced by morphine and the possible mechanism

Agmatine is the endogenous ligand of imidazoline receptor, it enhanced morphine analgesia, inhibited tolerance to and physical dependence on morphine. In the present study, the effect of agmatine on the psychological dependence on morphine and the possible mechanism was evaluated.     

Agmatine modulates neuroadaptations of glutamate transmission in the nucleus accumbens of repeated morphine-treated rats

It has been proved that agmatine inhibits opioid dependence, yet the neural mechanism remains unclear. In the present study, the effect of agmatine on the neuroadaptation of glutamate neurotransmission induced by morphine dependence, including changes of the extracellular glutamate level and glutamate receptors in the nucleus accumbens was investigated.We found that agmatine (2.5–20 mg/kg, s.c.) inhibited development of morphine dependence, which was consistent with our previous report. In rats repeatedly treated with morphine, the glutamate level in the nucleus accumbens dialysate was markedly increased after naloxone-precipitated withdrawal. When agmatine (20 mg/kg, s.c.) was co-pretreated with morphine or was applied before naloxone-precipitated withdrawal, this elevation of the extracellular glutamate level was inhibited. In the synaptosome model, repeated morphine treatment and naloxone precipitation induced an increase in glutamate release, while agmatine (20 mg/kg, s.c.) co-pretreated with morphine reversed the increase of glutamate release. However, neither morphine or agmatine treatment alone nor morphine and agmatine co-administration had any influence on [3H]-glutamate uptake. It indicated that the elevation of the glutamate level in the nucleus accumbens might be caused by the increase of glutamate release of synaptosome in the withdrawal conditions of morphine-dependent rat. Furthermore, agmatine concomitant treatment with morphine entirely abolished the up-regulation of the NR1 subunit of N-methyl-d-aspartate (NMDA) receptors in the nucleus accumbens in repeated morphine-treated rats.Taken together, the present study demonstrated that agmatine could modulate the neuroadaptations of glutamate transmission in the nucleus accumbens in the case of morphine dependence, including modulating extracellular glutamate concentration and NMDA receptor expression.     

Interactions of thyrotropin releasing hormone, its metabolites and analogues with endogenous and exogenous opiates

The interactions of thyrotropin releasing hormone, its metabolites and synthetic analogues with acute and chronic effects of endogenous and exogenous opiates have been described. The endogenous and exogenous opiates are represented by beta-endorphin and morphine, respectively. The pharmacological effects of opiates include analgesia, temperature effects, respiratory depression, catalepsy, locomotor activity, opiate receptor binding, tolerance, and physical dependence. Thyrotropin releasing hormone and related compounds appear to (a) antagonize hypothermia, respiratory depression, locomotor depression and catalepsy but not the analgesia induced by opiates, (b) inhibit the development of tolerance to the analgesic effect but not to the hypothermic effect of opiates, (c) inhibit the development of physical dependence on opiates as evidenced by the inhibition of development of certain withdrawal symptoms, and (d) suppress the abstinence syndrome in opiate dependent rodents. Thyrotropin releasing hormone does not interact with the opiate receptors in the brain. Potential therapeutic applications of thyrotropin releasing hormone and its synthetic analogues in counteracting some of the undesirable effects of opiates are discussed.     

Heterocyclic and piperonylic acid esters of 1-methyl-4-piperidinol as analgesics.

Heterocyclic and piperonylic acid esters of 1-methyl-4-piperidinol were synthesized and evaluated for analgesic activity. 1-Methyl-4-piperidinol 4-piperonylate (14) exhibited activity in the codeine range (mouse hot plate). In monkeys, 14 acted neither as a typical narcotic agonist nor as a typical antagonist and it showed no physical dependence liability of the morphine type. The nonquaternary C-4 peperidinol esters 1a, 4, 8, and 14 exhibited marginal to virtually no binding to the opiate receptor in rat brain homogenates. The interaction of various functional groups of this series with potential binding sites of a nonopiate type receptor is discussed.