Naloxone injections into the periaqueductal grey area and arcuate nucleus block analgesia in defeated mice

In a situation of social conflict, mice that are defeated by an opponent exhibit a marked analgesia. Microinjections of naloxone (1 or 10 g) into the periaqueductal grey area (PAG) or into the region of the arcuate nucleus prior to the defeat prevented the emergence of analgesia. Microinjections of morphine (5 g) into these sites had previously been shown to produce profound analgesia. Mice whose adrenals were removed rapidly developed analgesia when attacked by a stimulus animal. Injection of naloxone into PAG also antagonized defeat-induced analgesia in adrenalectomized mice. These observations indicate that sites and processes in the brain rather than in the periphery are responsible for the development of analgesia in mice that are subjected to social defeat.     

Species differences in the relative analgesic potencies of some classical opiates and opioid peptides

The analgesic ED₅₀ values of some classical morphine congeners (morphine, methadone, fentanyl, azidomorphine) in the rat and mouse tail-flick tests were found to be similar. However, several synthetic derivatives of the natural enkephalins were more potent in mice than in rats. (These analogs contain d-amino acid in position 2 and d- or l-sulfonic (or phosphonic) acid residue in position 5). -Endorpin, d-Met², Pro⁵-enkephalinamide and two partial agonists showed intermediate interspecies relative potencies. According to the data obtained, similar opiate receptors might mediate the analgesic action of classical opiates in rats and in mice. However, the opiate receptors responsible for the antinociceptive effects of the above mentioned enkephalin analogues must be dissimilar in the two species examined. The results are discussed in terms of the role of - and -receptors in mediation of the analgesic effect induced by different types of opioids.     

人工流产术前宫颈及子宫内膜麻醉的镇痛效果探讨

目的　探讨宫颈与子宫内膜两部位联合麻醉、普鲁卡因与利多卡因两药物配合应用在人工流产术中的镇痛效果。方法　人工流产术前对麻醉组 10 6例行普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉。术中记录受术者腹痛程度、无阻力插入宫颈内口的扩张器号、出血量、人流综合征例数等指标。按照世界卫生组织规定疼痛标准及人工流产综合征反应进行评价 ,同期选择按传统机械扩宫法 10 4例做对照。结果　麻醉组镇痛有效率95 3% ,宫口松驰有效率 95 3% ,人流综合征无 1例发生。两组比较P均 <0 0 0 1。两组出血量比较无差异 ,无利多卡因毒性反应发生。结论　人工流产术前普鲁卡因宫颈浸润麻醉和利多卡因子宫内膜表面麻醉镇痛效果显著 ,可大大降低人流综合征的发生 ,避免利多卡因的毒性反应     

妇科术后硬膜外腔注射吗啡镇痛效果观察

对妇科术后硬膜外腔注射吗啡镇痛效果进行观察分析探讨。对３ａ来我院使用术后硬膜外腔注射吗啡镇痛效果进行评定,对血压、脉博等情况观察进行总结分析。结果：硬膜外腔注射吗啡术后镇痛效果优８５．６％,良６．８％。副作用有血压下降达２７．８％、恶心呕吐１５．５％,头晕２３．０％。     

异氟醚分娩镇痛对母体血液动力学的影响

目的：前瞻性研究异氰醚分娩镇痛对母体血液动力学的影响。方法：应用国产无创性血液动力学测试仪,对分娩活跃期异氟醚分娩镇痛和对照组产妇共３０例的血液动力学状况进行检测。结果：;实验前后,各组母体血液动力学参数;心率（ＨＲ）,每搏量（ＳＶ）,每搏指数（ＳＩ）,心输出量（ＣＯ）,心脏指数（ＣＩ）,左室有效泵力（ＶＰＥ）,平均动脉压（ＭＡＰ）和总外周阻力（ＴＰＲ）均无显著差异;两组间无显著差异。     

Antisense mapping KOR-1: evidence for multiple kappa analgesic mechanisms

In binding assays, both dynorphin B and alpha-neoendorphin are relatively selective for the kappa1b site, unlike U50,488H which has high affinity for both kappa1a and kappa1b sites. In vivo, U50,488H, dynorphin B and alpha-neoendorphin analgesia are reversed by the kappa1-selective antagonist, nor-binaltorphimine (norBNI). Antisense mapping the three exons of KOR-1 revealed that probes targeting all three exons blocked U50,488H analgesia, as expected. However, the selectivity profile of dynorphin B and alpha-neoendorphin analgesia towards the various antisense oligodeoxynucleotides differed markedly from U50,488H, implying a different receptor mechanism of action.     

Evidence for opiate-activated NMDA processes masking opiate analgesia in rats

The acute interaction between opioid receptors and N-methyl-D-aspartate (NMDA) receptors on nociception was examined in rats using tail-flick and paw-pressure vocalisation tests. When injected at various times (1 to 6 h) after morphine (5 to 20 mg/kg, i.v.) or fentanyl (4x40 microgram/kg, i.v.), the opioid receptor antagonist naloxone (1 mg/kg, s.c.) not only abolished the opiate-induced increase in nociceptive threshold, but also reduced it below the basal value (hyperalgesia). The noncompetitive NMDA receptor antagonist MK-801 (0.15 or 0.30 mg/kg, s.c.) prevented the naloxone-precipitated hyperalgesia and enhanced the antinociceptive effects of morphine (7.5 mg/kg, i.v.) and fentanyl (4x40 microgram/kg, i.v.). These results indicate that the antinociceptive effects of morphine and fentanyl, two opiate analgesics widely used in humans in the management of pain, are blunted by concomitant NMDA-dependent opposing effects which are only revealed when the predominant antinociceptive effect is sharply blocked by naloxone. This study provides new rationale for beneficial adjunction of NMDA receptor antagonists with opiates for relieving pain by preventing pain facilitatory processes triggered by opiate treatment per se.     

Patient-controlled intranasal diamorphine for postoperative pain: an acceptability study

A patient acceptability study was conducted using patient-controlled intranasal diamorphine. Patients undergoing nonemergency orthopaedic or gynaecological surgery self-administered intranasal diamorphine for 24 h postoperatively. Pain, pain relief, sedation, respiratory rate, nausea and vomiting were assessed regularly. After 24 h, patients and their attending nurses completed a questionnaire assessing satisfaction and practical aspects of the technique. Satisfaction was reported as good or complete by 69% of patients and 69% of nurses. Pain relief was assessed as better than expected by 45% of patients and better than normal by 50% of nurses. Seventy-nine per cent of patients would be pleased to use patient-controlled intranasal diamorphine again and 89% of nurses would be happy for their patients to use it again. Sedation was uncommon and mild and there were no episodes of significant respiratory depression. Fifty-three per cent of patients reported no nausea and 74% did not vomit at any stage. There were seven withdrawals, four due to problems with the device and three due to therapeutic problems. The nasal spray may need modification to improve reliability. However, we found patient-controlled intranasal analgesia an effective technique, which was well tolerated by patients and nurses and was without unpleasant side-effects. Further work to determine how it performs compared with intramuscular or intravenous analgesia is now needed.     

硬脂酸纳米吗啡用于硬膜外镇痛的实验研究

目的 观察硬脂酸纳米吗啡(SLN-M)单次注入大鼠硬膜外腔后的镇痛效应.方法 选择硬膜外置管后无神经损伤症状的SD雄性大鼠50只,随机均分为五组.A组(假给药组):经硬膜外腔给予硬脂酸纳米(SLN);B1组与B2组:分别给予0.2及1 mg普通吗啡;C1组与C2组:分别给予含0.2及1 mg吗啡的SLN-M.用药后测定热痛阈值评价镇痛效果,以最大镇痛效应(MPE)表示,以SpO2、角膜反射的变化、僵直症的发生率对药物不良反应进行评估.结果 B1与C1组及B2与C2组的MPE最高值差异无统计学意义.但随时间延长,B1与B2组MPE逐渐下降,12 h后开始显著低于C1与C2组(P＜0.05).B1与B2组达到MPE最高值的时间显著快于C1与C2组(P＜0.05),但持续时间显著缩短(P＜0.05).B1与B2组SpO2显著低于C1与C2组(P＜0.05),角膜反射的变化和僵直症的发生率要高于C1与C2组(P＜0.05),且与吗啡剂量呈正相关.结论 硬膜外腔单次给予SLN-M后可达到与普通吗啡一样的镇痛效果,有效镇痛时间明显延长,不良反应显著降低.     

硬膜外阻滞在中期妊娠引产镇痛时机选择的临床观察

目的：比较硬膜外阻滞在中期妊娠引产不同时点开始镇痛的临床效果。方法选取我院60例因计划外妊娠或有胎儿畸形等妊娠合并症要求终止妊娠者,随机分为两组实施硬膜外阻滞,A组为病房常规处理后产妇有疼痛感即开始实施麻醉,B组为病房常规处理后有规律宫缩开始实施麻醉,每组30例;记录镇痛开始前及镇痛后生命体征、各时点孕妇的VAS评分和运动神经阻滞分级、引产时间、出血量及不良反应情况。结果与B组比较,A组在镇痛后各时点VAS评分降低、引产时间延长,差异均有统计学意义（P＜0.05）;两组间孕妇引产期间生命体征平稳,出血量及不良反应差异无统计学意义（P＞0.05）。结论中期妊娠引产无须考虑胎儿因素,早期实施麻醉镇痛干预更为合理,在不增加出血量和不良反应的基础上引产时间略有延长。