三种非阿片小肽对吗啡耐受调节的研究进展

吗啡等阿片类镇痛药反复使用造成的镇痛耐受是临床上的一大难题.近期的研究表明,内皮素、P物质前体分子-前体速激肽及黑皮素等三种非阿片小肽与吗啡镇痛和耐受密切相关.内皮素通过内皮素A受体(ETAR)、黑皮素通过黑皮素4受体(MC4R)分别以不同机制调节吗啡镇痛并能够预防其耐受的发生,而前体速激肽则可能是调控吗啡镇痛和耐受的关键分子,本文综述了上述非阿片小肽对吗啡耐受调节的研究进展,以期为吗啡耐受的治疗提供新的思路.     

电压门控钙通道及其对阿片类物质药理作用的调节

电压门控型钙通道依据其生理和药理特性可分为L，N，P／Q，R，T等型。L型钙通道阻断剂能增强阿片类物质镇痛，抑制阿片类物质的耐受和依赖，其作用机制与阻断钙通道、激活阿片受体、影响阿片代谢、抑制蛋白激酶及神经递质的释放有关。N型钙通道阻断剂具有明显的镇痛作用，尤其对神经源性痛具有强大的镇痛作用，且此作用不易耐受，作用机制与抑制C纤维和细的Aδ纤维活化及Ca^2＋介导的炎性因子的合成相关。N型钙通道阻断剂也能增强吗啡镇痛。P／Q型钙通道阻断剂对锐痛和炎性痛的镇痛作用比吗啡更佳，作用机制与N型钙通道阻断剂相类似。T型钙通道阻断剂对神经源性痛有一定的镇痛作用，能增强阿片类物质镇痛，预防和治疗阿片类物质的耐受和依赖，作用机制与抑制C纤维及细的Aδ纤维活化、抑制阿片受体信号转导通路和效应器系统及去甲肾上腺素的释放有关。作者综述了电压门控钙通道在调节阿片类物质的药理作用方面的研究进展。     

盐酸纳洛酮在急症中的应用及其副作用

盐酸纳洛酮为羟二氢吗啡酮的衍生物 ,是阿片受体的拮抗剂 ,并且无激动活性 ,与阿片受体的亲和力大于吗啡和脑啡肽。能竞争性地阻止并取代阿片样物质与受体结合 ,从而起到阿片中毒的解救效果[1] 。 6 0年代国外在临床应用纳洛酮治疗麻醉剂与麻醉剂过量引起的休克、急性呼吸抑制等方面已取得一定效益。近年来 ,对镇痛原理的深入研究发现 ,盐酸纳洛酮在某些神经 ,心血管及内分泌代谢等内环境失调疾病中起主要作用。1　盐酸纳洛酮的药代动力学及生物利用度盐酸纳洛酮脂溶性高 ,吸收后能迅速分布全身 ,尤其在脑、肾、肺、心中分布较高 ,分布的容…     

二氢埃托啡的临床溢用现象及回顾性思考

二氢埃托啡(Dihydroetorphine,DHE)是我国研制的镇痛药,于1991年上市。DHE为阿片受体纯激动剂,对μ受体的选择性和亲和力很高,具有强效镇痛作用。其镇痛强度为吗啡的12000倍。同吗啡相比,治疗剂量的DHE引起的呼吸抑制作用较轻。     

浅谈纳洛酮在中毒救治中的应用

纳洛酮(Naloxone，NX)又名烯丙羟吗啡酮，为羟(二)氢吗啡酮衍生物，是相对纯化的竞争性阿片受体拮抗剂。内源性阿片肽样物质主要有三类：β-内啡肽类、脑啡肽类及强啡肽．NX能竞争性抑制阻断并取代阿片肽样物质与阿片受体结合从而阻断阿片肽样物质的作用产生临床疗效。下面就NX在抢救酒精中毒、一氧化碳(CO)中毒、镇静催眠药中毒、麻醉药中毒中的应用作一简述。     

二氢埃托啡的临床滥用现象及回顾性思考

二氢埃托啡(Dihydroetorphine,DHE)是我国研制的镇痛药,于1991年上市.DHE为阿片受体纯激动剂,对μ受体的选择性和亲和力很高,具有强效镇痛作用.其镇痛强度为吗啡的12 000倍[1].同吗啡相比,治疗剂量的DHE引起的呼吸抑制作用较轻.     

吗啡依赖状态下大鼠脑组织左旋精氨酸脱羧酶活性的测定

阿片类药物的耐受和躯体依赖不仅与阿片受体本身的代偿性适应有关,而且还涉及到许多非阿片受体和递质系统.一方面当改变这些非阿片受体的功能后会影响阿片类药物的药理作用,例如抑制5-HT重吸收可以增加吗啡镇痛[1];另一方面阿片类药物慢性处理会引起这些受体系统发生代偿性适应性变化,例如吗啡急性处理能抑制5-HT释放,而慢性处理反而导致5-HT释放增多[2].     

胍丁胺-I1咪唑啉受体对μ-阿片受体脱敏和下调的影响

目的:观察胍丁胺通过激活I1咪唑啉受体对阿片预处理引起的μ-阿片受体脱敏和下调的影响.方法:以CHO-μ和CHO-μ/IRAS (imidazoline receptor antisera-selected protein,咪唑啉受体抗血清选择性蛋白)细胞作为研究对象,用[35S]GTPγS和3H-二丙诺啡(diprenorphine)结合实验方法,确定胍丁胺-I1咪唑啉受体作用系统对μ-阿片受体脱敏和下调的影响.结果:在正常CHO-μ和CHO-μ/IRAS细胞中,μ-阿片受体的表达量和对配体的亲和力无显著差异;两细胞中μ-阿片受体对激动剂刺激的反应一致.阿片受体激动剂DAMGO[(D-Ala2,N-Me-Phe4,Gly5-ol)-脑啡肽(enkephalin),10 μmol/L]处理CHO-μ/IRAS细胞30 min μ-阿片受体出现脱敏,而胍丁胺(10 nmol/L～100 μmol/L)不影响μ-阿片受体脱敏过程.DAMGO(1 μmol/L)处理两细胞12 h后可出现μ-阿片受体的下调,胍丁胺(1～100 nmol/L)浓度依赖性地抑制CHO-μ/IRAS细胞中μ-阿片受体的下调,而相同浓度胍丁胺在CHO-μ细胞中无此作用.胍丁胺这一作用能被I1咪唑啉受体阻断剂依法克生(efaroxan,Efa)所阻断.结论:胍丁胺通过激活I1咪唑啉受体可抑制DAMGO长期处理所致的μ-阿片受体下调,此作用可能与胍丁胺抑制阿片依赖有关.     

反义寡聚核苷酸对阿片类药物药理作用的影响

阿片受体及受体后信号转导分子的反义寡聚核苷酸能影响相应阿片受体亚型激动剂的药理作用 ,其中包括阿片类药物的镇痛及其所致的耐受和依赖。其作用机制可能与抑制阿片受体表达 ,减少阿片受体量 ,影响受体后信号转导分子功能有关。这方面的研究对直接在分子水平探讨特定阿片受体的功能 ,阿片受体分型 ,分析阿片类药物产生镇痛、耐受和依赖等一系列药理作用的确切机制具有重要意义     

梭曼中毒影响γ-氨基丁酸系统吗?

用体外放射性配体结合实验方法检测了梭曼对牛小脑γ-氨基丁酸(GABA)受体和GABA摄取的影响.10~(-3)～10~(-6)M未影响GABA受体结合;对GABA摄取有轻微抑制IC_(50)为1.4×10~(-3)M.这一结果未能支持加拿大学者Lundy关于梭曼中毒有可能影响GABA受体结合的假设.对梭曼中毒与GABA系统的关系进行了讨论.     

A specific immunoassay for the determination of morphine and its glucuronides in human blood

The development of specific antisera for immunochemical determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide is described. Morphine was N-demethylated to normorphine and N-alkylated to give N-aminopropyl-normorphine as hapten for antisera against morphine. As haptens for antisera against morphine-3-glucuronide and morphine-6-glucuronide, N-aminopropyl-nor-morphine was glucuronidated in position 3 or 6 respectively. Each of these three haptens were coupled to BSA employing the glutaraldehyde method to obtain three different immunogens. Immunisation of rabbits with these conjugates gave anti-morphine, anti-morphine-3-glucuronide and anti-morphine-6-glucuronide antisera, which were tested in a competitive, heterogeneous radioimmunoassay. Tracers for this radioimmunoassay procedure were synthesised by substitution of morphine and morphine-6-glucuronide in position 2 with ¹²⁵I and indirect iodination of the morphine-3-glucuronide hapten according to the method of Bolton and Hunter. The resulting antisera show very specific reactions with morphine, morphine-3-glucuronide and morphine-6-glucuronide. Cross reactivities of each antiserum with structurally related opiates and opioides are very low. The cross reactivities of the anti-morphine antiserum against morphine-3-glucuronide, morphine-6-glucuronide, codeine, codeine-6-glucuronide or dihydrocodeine were less than 0.3%, the anti-morphine-3-glucuronide antiserum against morphine, morphine-6-glucuronide, codeine, codeine-6-glucuronide or dihydrocodeine less than 0.1% and the anti-morphine-6-glucuronide antiserum against morphine, morphine-3-glucuronide, codeine or dihydrocodeine less than 0.1%, against codeine-6-glucuronide less than 2.3%. The determination of morphine, morphine-3-glucuronide and morphine-6-glucuronide in blood samples (limit of detection = 3, 1, 0.5 ng/g) of nine cases of fatal heroin overdose with this radioimmunoassay method and the comparison with a GC/MS method is described. Received: 22 December 1997 / Received in revised form: 23 March 1998     

Antibody-mediated clean-up of blood for simultaneous HPLC determination of morphine and morphine glucuronides

For the interpretation of the concentration of morphine in blood samples of heroin consumers information about the concentration of the analgesic active morphine metabolite morphine-6-glucuronide is very important. Thus a simple but specific clean-up procedure based on immuno-affinity chromatography is presented for the extraction of morphine, morphine-3-glucuronide and morphine-6-glucuronide from whole blood in cases of fatal heroin overdose. The preparation of the immunoabsorber by immobilization of antibodies against morphine-3-BSA and morphine-6-KLH with carbonyldiimidazole-activated trisacrylgel is described. The separation of the extracts is achieved by HPLC using native fluorescence detection. The limits of detection for this method are 10 ng for morphine and morphine glucuronides/g blood. The results for the concentration of morphine and morphine glucuronides in blood from seven cases of heroin overdose are presented. By calculating the quotients for the concentrations of morphine-6-glucuronide/morphine the time elapsed since the last intake of heroin is estimated. Received: 10 November 1996 / Received in revised form: 19 February 1997     

Four nonfatal and six fatal cases of opiate use: utility of morphine, its metabolites, and their ratios in blood specimens

Four nonfatal and six fatal cases of opiate use are presented with careful toxicological analysis. Levels of morphine (M), 6-monoacetylmorphine (6-MAM), morphine-6-glucuronide (M6G), and morphine-3-glucuronide (M3G) in blood specimens were measured by the sophisticated method of liquid chromatography (LC)-electrospray ionization (ESI)-tandem mass spectrometry (MS-MS). Fatal cases were characterized by much higher levels of free M than the nonfatal cases; this caused lower ratios of M6G/M and M3G/M in the fatal cases when compared with the nonfatal cases. Among the six fatal cases, the M6G/M ratios were especially low in four cases, in which rapid deaths were estimated. The present data are compared with data previously reported by other groups, and we discuss the utility of the levels of M, M6G, and M3G in blood and their ratios for estimating the antemortem status of each individual.     

Direct quantification of morphine glucuronides and free morphine in urine by liquid chromatography–tandem mass spectrometry

A simple and robust liquid chromatographic-tandem mass spectrometric method was developed and validated for the direct quantification of the structural isomers morphine-3-glucuronide (M3G), morphine-6-glucuronide (M6G), and morphine in urine. Method development showed that dilution of the urine samples was mandatory to obtain reproducible chromatography and that the use of deuterated internal standards was needed to compensate for ion suppression. Sample preparation consisted of a 20-fold dilution of urine into the internal standard solution. Chromatography was performed on a C₈-column using gradient conditions. The mobile phase consisted of water/methanol, both containing 0.1 % acetic acid and 1 mM ammonium acetate. Calibration curves were constructed between 0.05 and 2 μg/ml. Validation data showed biases ranging from 1.5 to 5.2 % for M3G, −2.7 to −5.9 % for M6G, and 3.7 to 7.1 % for morphine. Imprecision never exceeded 5.2, 5.9, and 5.7 % for M3G, M6G, and morphine, respectively. The applicability of the method was checked by the analysis of 20 urine samples that were analyzed concurrently with a routine gas chromatography-mass spectrometry method. Results showed good correlation between the methods with a correlation coefficient of approximately 0.95.     

Metabolism and metabolomics of opiates: A long way of forensic implications to unravel

Opium poppy has important medical, socioeconomic, forensic and political implications. More than 80 benzylisoquinoline alkaloids have been described, many of them with relevant therapeutic properties such as morphine, codeine, papaverine and noscapine. Heroin, a semi-synthetic drug produced from morphine is a worldwide serious cause of morbidity and mortality. Heroin dependence is complex phenomenon with environmental and genetic influence, and several biomarkers of exposure have been proposed. This work aims to review the metabolism and metabolomics of opiates with particular interest on their relevance as potential clinical and forensic antemortem and postmortem biomarkers. It is known that the heroin is mainly a prodrug that is rapidly deacetylated in blood to its active metabolite, 6-acetylmorphine, which is then subsequently slowly deacetylated to morphine. Therefore, 6-acetylmorphine has been used as the main target metabolite to prove heroin abuse in clinical, but mostly in forensic routine. Nevertheless, its applicability is limited due to the reduced detection window. Therefore, morphine (and its metabolites morphine-3-glucuronide and morphine-6-glucuronide), codeine, codeine-6-glucuronide, 6-acetylcodeine, noscapine (and its metabolites meconine, desmethylmeconine, and cotarnine), papaverine (and its metabolites 6-desmethylpapaverine, hydroxypapaverine, dihydroxypapaverine, 6-desmethylpapaverine-glucuronide) and thebaine (and acetylthebaol and the non-acetylated analog thebaol) have been additionally recommended to obtain the most reliable results possible. More recently, the identification by metabolomics analysis of several endogenous compounds offered an alternative approach of significant importance to uncover toxic effects. Profound alterations in the neurotransmitters levels and energy and amino acid metabolism have been reported with l-tryptophan, 5-hydroxytryptamine and 5-hydroxyindoleacetate being suggested as potential non-specific biomarkers of long-term heroin addiction. These endogenous metabolic profiles and exogenous components that together comprise the exposome will certainly help to uncover metabolic disturbances and patterns that may be associate to addiction with relevant clinical and forensic implications.     

Postmortem distribution pattern of morphine and morphine glucuronides in heroin overdose

The postmortem distribution of morphine and its metabolites was investigated in four cases of heroin overdose to evaluate some of the factors that influence intravasal blood concentrations. Variables included were the chemical stability of morphine conjugates, hemoconcentration, incomplete distribution of the drug and diffusion processes. Blood samples from different sampling sites including the aorta, the infra- and suprarenal portion of the inferior vena cava, the superior vena cava, the femoral and subclavian veins, and the right and left ventricles were examined for morphine, morphine-3-glucuronide and morphine-6-glucuronide, hematocrit and water content. Drug concentrations were determined by HPLC based on the native fluorescence of the analytes. Morphine glucuronides proved to be stable for a time period of 72 h. The water content ranged from 65 to 83% and hematocrit values from 25 to 75%, and were seen as contributory factors to the dramatic differences observed for drug concentrations from different sampling sites. The differences could neither be attributed to incomplete distribution during life-time nor to a diffusion process following the different distribution volumes of morphine and its conjugates. A definite relationship between the ratio of the molar concentrations of morphine and its glucuronides, as assessed in pharmacokinetical studies after morphine dosing, could not be established. For a better understanding more cases and changes over time and tissue concentrations should be analysed.     

Lack of impairment due to confirmed codeine use prior to a motor vehicle accident: Role of pharmacogenomics

BackgroundWe examined forensic serum toxicology and pharmacogenomics data from a woman on codeine shortly before she caused a motor vehicle accident.MethodsA woman driving erratically collided with a parked car of a highway seriously injuring 2 men working to repair the parked vehicle. The woman tested positive for codeine, acetaminophen and barbital. She had been taking these medications for 20 years due to migraine headache. Serum toxicology and genotype analysis for cytochrome P450, UDP glucuronosyltransferase, and other metabolizing enzymes were measured.ResultsThe woman was tried and convicted of driving under the influence resulting in bodily harm and was sentenced to 6 years. Toxicology results on peripheral blood showed a total and free codeine of 840 and 348 μg/L, respectively, and total morphine of 20 μg/L (17, 3, and 0 μg/L for morphine-3-glucuronide, morphine-6-glucuronide, and free morphine, respectively). She was heterozygous for CYP 2D6 *2/*4 (extensive/poor metabolism) and heterozygous for UGT 2B7 *1/*2 (extensive/ultra-rapid metabolism). The woman was also taking fluoxetine and bupropion which are strong inhibitors of CYP 2D6.ConclusionsBased on her genotype and phenotype and reports by the arresting officer, we suggest that the subject in question was not intoxicated by opiates at the time of her motor vehicle accident and may have been falsely incarcerated.     

Time-dependent postmortem redistribution of morphine and its metabolites in blood and alternative matrices—application of CT-guided biopsy sampling

Interpretation of postmortem morphine concentrations in forensic toxicology provides several pitfalls such as missing information on tolerance, analyte stability, or postmortem redistribution (PMR). Recently, it had been shown that computed tomography (CT)-guided collection of biopsies using a robotic arm (virtobot) provides a valuable strategy for systematic studies on time-dependent PMR. Using this technique, time-dependent PMR of morphine and its metabolites was investigated in 12 cases. At admission to the institute (t1), femoral and heart blood (right ventricle) as well as biopsies from the right lung, the right kidney, liver, spleen, and muscle tissue were collected. At autopsy approximately 24 h later (t2), samples from the same body regions were collected again. Additionally, gastric contents, urine, brain tissue, and heart blood from the left ventricle was collected. Morphine, normorphine, hydromorphone, morphine-3-glucuronide, morphine-6-glucuronide, and morphine-sulfate were quantified with LC-MS/MS. In femoral blood, significant increase of morphine concentrations was observed, although ultimately not relevant for forensic interpretation. In the alternative matrices, increases as well as decreases were observed without a clear trend. The morphine metabolites did not exhibit relevant concentration changes. Investigation of underlying redistribution mechanisms indicated that concentration change (i.e., increase) of morphine in femoral blood rather resulted from diffusion processes than from release of morphine from its conjugates. Concentration changes in heart blood might have been caused by redistribution from lung tissue or gastric content. This study also proved that CT-guided collection of biopsies using a virtobot arm is an invaluable tool for future studies on PMR redistribution of other substance groups.

     

Postoperative analgesic effects of intra-articular bupivacaine and morphine after arthroscopic cruciate ligament surgery

Intra-articular administration of local anaesthetics such as bupivacaine can produce short-term postoperative analgesia in patients undergoing diagnostic arthroscopy or arthroscopic meniscectomy. A peripheral anti-nociceptive effect may also be induced by the administration of intra-articular opiates interacting with local opioid receptors in inflamed peripheral tissue. In the present study we aimed to study the analgesic effects of intraarticularly given bupivacaine and morphine sulphate (as well as the combination of both drugs) on postoperative pain. In a prospective, randomized, double-blind manner 40 patients received one of the following: (a) morphine (1 mg in 20 ml NaCl), (b) bupivacaine (20 ml, 0.375%), (c) combination of both or (d) saline (20 ml, control group) intra-articularly at the end of arthroscopic anterior cruciate ligament (ACL) reconstruction. The postoperative pain was assessed via a visual analogue scale (VAS) during the first 48 h after surgery, and supplemental analgesic requirements were noted. All comparisons were made versus the control group receiving saline. The pain scores were significantly lower in the morphine group at 24 and 48 h, and in the bupivacaine group at 2, 4 and 6 h after surgery. In the group that received a combination of both bupivacaine and morphine, the pain scores were significantly reduced throughout the whole postoperative observation period. No side-effects or complications from therapy were seen in any of the groups. The conclusion of this study is that intra-articular morphine is effective in the postoperative period after arthroscopic ACL reconstruction. The combination of bupivacaine and morphine was the most effective postoperative analgesic regimen and resulted in significant analgesia throughout the whole 48-h period following surgery. Patients receiving the combination of bupivacaine and morphine had a significantly shorter hospital stay than the control group.     

Cross-reactivity of the CEDIA buprenorphine assay with opiates: an Austrian phenomenon?

When testing the Microgenics CEDIA assay for immunological buprenorphine analysis, cross-reactivity between the buprenorphine reagents and opiates was observed at concentrations higher than 120 mg/l morphine, 320 mg/l methadone, 30 mg/l codeine, 60 mg/l dihydrocodeine and 520 mg/l morphine-3-glucuronide. The cross-reactivity with morphine has the greatest impact on routine screening as opiate maintenance therapy in Austria is also performed with slow-release oral morphine. The use of a second cutoff value of 30 g/l for urine samples that are (immunologically) positive for opiates is therefore suggested, compared to the cutoff value of 5 g/l proposed by the manufacturer.