Mechanisms mediating the brain stem control of somatosensory transmission in the dorsal horn of the cat's spinal cord: an intracellular analysis

Summary The effect of brainstem stimulation was studied on neurones recorded intracellularly in the superficial and deeper laminae of the lumbosacral dorsal horn of the spinal cord in anaesthetised cats. Stimulation in the nucleus locus coeruleus (LC) produced a hyperpolarisation in 4/13 multireceptive neurones and produced a biphasic action consisting of a hyperpolarisation which was followed by a depolarisation in 3/13 neurones. These actions were produced irrespective of whether the multireceptive neurone was located in the superficial or deeper laminae of the dorsal horn. Stimulation failed to produce postsynaptic potentials in the remaining 6/13 multireceptive neurones. The amplitude of hyperpolarisation was increased by the passage of depolarising pulses through the recording microelectrode and decreased by hyperpolarising pulses. Stimulation in other brainstem areas such as, the lateral (FTL), paralemniscal (FTP) and central (FTC) divisions of the tegmental field and the nuclei raphe magnus (NRM) and reticularis magnocellularis (RMc) also hyperpolarised neurones in the dorsal horn. The polarity of hyperpolarisation evoked from some brainstem areas (FTP, FTC, RMc) could be reversed to depolarisation by the passive diffusion of ions from the recording microelectrode containing 3M-KCl. Brainstem (LC, NRM, FTP, FTL) stimulation generated long lasting (700 ms) hyperpolarisation on 4/4 selectively nocireceptive neurones of lamina I. There was, however, no effect on the activity of 5/5 neurones recorded in laminae I/II which in addition to receiving excitatory cutaneous inputs were inhibited by heat stimuli. Stimulation in LC also produced dorsal root potentials (DRPs) and reduced the amplitude of simultaneously recorded excitatory postsynaptic potentials (EPSPs) generated by the activation of primary afferent fibres in 3 multireceptive neurones. It is concluded that inhibition of nociceptive transmission in the spinal cord from LC and other brainstem areas may involve both pre- and postsynaptic mechanisms.     

Prenatal nicotine exposure increased duration of nicotine-induced analgesia in adult rats

The effect of prenatal exposure to nicotine on nicotine-induced analgesia was studied in rats. The analgesic effect of a single dose of nicotine (1 mg/kg SC) was measured by the tail-flick technique, and two subsequent studies were carried out. In the first study, 7-month-old male rats, born to dams chronically treated with nicotine during pregnancy (NIC), exhibited prolonged nicotine-induced analgesia compared to matched controls. The second study was designed to explore whether rats prenatally exposed to nicotine (NIC rats) are born with an increased sensitivity to nicotine and whether there is any sex difference. The analgesic effect of nicotine was tested on control and NIC rats of both sexes once a month from 2 to 7 months of age. At an early age, male but not female NIC rats, exhibited shorter analgesic responses to nicotine than did the matched controls. With increasing age, however, the duration of nicotine analgesia began to be prolonged in NIC rats of both sexes. Significant differences between control and NIC rats were found at the age of 6 and 7 months, in both sexes. Thus, rats prenatally exposed to nicotine are not born with an increased sensitivity to the analgesic effect of a single dose of nicotine. This phenomenon develops later, during the course of life, independently of gender.     

国产 89SrCl2治疗肿瘤骨转移灶所致骨痛临床多中心研究

目的　验证上海科兴药业公司提供的89SrCl2 注射液治疗转移性骨肿瘤所致骨痛的疗效。方法　试验采用随机、双盲、阳性药物 (英国Amersham公司生产的Metastron)对照 ,5个中心参加验证。对 90例原发病灶诊断明确的恶性肿瘤骨转移患者进行骨痛镇痛治疗 ,其中资料完整的Ⅰ组(验证组 ) 5 9例 ,Ⅱ组 (对照组 ) 2 9例 ,余 2例患者剔除。Ⅰ组中男 30例 ,女 2 9例 ,年龄 2 5～ 80 (5 9 95±13 80 )岁 ;原发性恶性肿瘤肺癌 2 1例 ,乳腺癌 2 4例 ,前列腺癌 12例 ,胃癌、肝癌各 1例 ;治疗前骨痛评分为 6～ 12 (7 5 9± 1 5 9)。Ⅱ组中男 11例 ,女 18例 ,年龄 35～ 91(5 8 93± 14 6 0 )岁 ;原发性恶性肿瘤肺癌 10例 ,乳腺癌 12例 ,前列腺癌 6例 ,胃癌 1例 ;治疗前骨痛评分为 6～ 9(7 14± 1 4 6 )。入选患者均以 14 8MBq静脉注射给药 ,疼痛得分大于 6 ,体力状况评分平均≤ 70分 ,患者预期生存期至少大于3个月。全身99Tcm 亚甲基二膦酸盐 (MDP)骨显像示多发骨骼放射性浓聚灶 ,并经实验室及其他影像学检查证实。治疗后观察 3个月。结果　Ⅰ组镇痛有效率为 6 2 71% (37 5 9例 ) ;其中无效占 15 2 4 %(9 5 9例 ) ,好转占 2 2 0 3% (13 5 9例 ) ,显效占 5 5 93% (33 5 9例 ) ,完全缓解占 6 78% (4 5 9例 )。Ⅱ组镇     

不同术后镇痛模式对红细胞免疫功能的影响

目的探讨不同术后镇痛模式对红细胞免疫功能的影响。方法50例妇科手术患者,按术后不同镇痛模式分为硬膜外自控镇痛(PCEA)组和静脉自控镇痛(PCIA)组。并分别于术前、术后1、3、7 d采静脉血样检测红细胞C3b受体花环率(RCR)、红细胞免疫复合物花环率(RICR)、红细胞免疫粘附促进因子(RFER)和红细胞免疫粘附抑制因子(RFIR)。结果与术前比,PCEA组术后1 d RCR、RFER显著上升(P<0.05),RFIR显著下降(P<0.05),术后3 d RCR、RFER仍显著上升(P<0.05),而RICR显著下降(P<0.05);PCIA组术后1 d RCR、RFER显著下降(P<0.05),RFIR、RICR显著上升(P<0.05);PCIA组术后1、3 d RCR、RFER比PCEA组显著降低(P<0.05),而RICR显著上升(P<0.05);两组各参数在术后7 d基本恢复至术前水平。结论PCEA对红细胞免疫功能的稳定和恢复作用明显强于PCIA。     

下丘脑弓状核注射神经降压素的镇痛效应及机制探讨

采用微量注射法,对37只大鼠进行了实验观察.结果如下:①下丘脑弓状核(ARC)注射神经降压素(NT)可使甩尾反应潜伏期(TFL)或痛阈显著升高.对照组注射生理盐水,TFL无明显变化.②ARC先注射纳洛酮,再注射NT,TFL变化值与单纯注射NT组相比明显下降.③ARC注射β-内啡肽(β-End)抗血清,再注射NT,TFL显著下降.④ARC注射生理盐水不影响注射NT的镇痛效应.上述结果表明,大鼠ARC注射NT可产生明显的镇痛效应,该效应可被ARC预先注射纳洛酮或β-内啡肽抗血清翻转,提示NT在ARC的镇痛作用,部分是由β-End介导的.     

白细胞介素—2新的功能位点及其中枢镇痛作用

白细胞介素－２（ＩＬ－２）不仅是重要的免疫调节因子，而且还具有重要的中枢调节作用。本实验以钾离子透入引起大鼠甩尾反应为指标，发现侧脑室注射ＩＬ—２能显著提高动物痛阈，并能被纳洛酮所阻断，表示ＩＬ－２的中枢镇痛作用可能与阿片受体有关。利用基因定位突变技术获得的无免疫活性ＩＬ－２实查体仍具有中枢镇痛作用，表明ＩＬ—２分子上发挥镇痛和免疫调节作用的功能位点是相互独立的。纳洛酮能够阻断ＩＬ—２的中枢镇痛作用，而不能影响ＩＬ—２增殖ＣＴＬＬ－２细胞的作用，提示ＩＬ－２发挥镇痛和免疫调节作用可能通过不同的受体途径。ＩＬ－２分子中第４５位Ｔｙｒ残基突变为Ｖａｌ后，虽仍保留了免疫活性，但丧失了镇痛功能，表示４５位Ｔｙｒ残基是ＩＬ—２发挥中枢镇痛功能的关键残基之一。我们推测ＩＬ—２的镇痛功能位点可能在ＩＬ—２分子中第４５位Ｔｙｒ残基附近区域。     

硬膜外控自动镇痛泵用于剖宫产术后临床观察

目的 :观察硬膜外腔自动镇痛泵 (AFA)用于剖宫产术后镇痛效果及对产后各项生理指标的影响。方法 :选择剖宫产术后患者 10 0例 ,随机分为两组 ,每组各 5 0例。硬膜外腔自动镇痛泵内含有 0 75 %布比卡因 15ml,0 5 %布比卡因 0 5ml,氟哌啶醇 5mg ,吗啡 8mg ,麻黄素 15mg ,生理盐水 80ml,以每小时 2ml速度给药 ,持续给药 48小时 ,对照组则不给任何药物。采用视觉模拟评分法 ,分别观察 2组患者术后的疼痛情况 ,肠蠕动恢复时间 ,拔尿管后排尿情况 ,产后出血、子宫复旧、泌乳情况及下床活动早晚情况 ,以及是否有恶心、呕吐、呼吸抑制等。结果 :①术后镇痛泵组患者术后无明显疼痛感 ,镇痛效果好 ,而对照组患者术后有明显疼痛感 (P <0 0 1) ;②镇痛泵组患者术后肠蠕动恢复时间为 (16 68±9 3 2 )h ,对照组 (16 2 3± 10 1)h ,两者比较无明显差异 (P >0 0 5 ) ;③术后尿管拔除后尿潴留发生率 ,镇痛泵组 8例 ,对照组 2例 ,差异有显著性 (P <0 0 5 ) ;④镇痛泵组下床活动时间为 (19± 5 )h ,明显早于对照组 (2 7± 8)h ,两组比较差异有显著性 (P <0 0 5 ) ;⑤ 2组患者产后出血、泌乳情况、子宫复旧、术后恶心呕吐、呼吸抑制发生情况比较 ,差异均无显著性(P >0 0 5 )。结论 :硬膜外自动镇痛泵具有良好的镇痛     

Survey of postoperative analgesia following ambulatory surgery

Background: The quality of pain relief during the first 48 hours following ambulatory surgery has been poorly documented. This questionnaire study was performed to evaluate the nature and severity of pain after the patient leaves the hospital. Methods: 1100 patients in the age group 5–88 years who underwent ambulatory surgery during a period of 6months were asked to complete a questionnaire 48 h after the end of the operation. In thecase of children, parents were asked to complete a similar questionnaire. The questions were related to pain experienced during the first 48 h after surgery and to the nature andseverity of postoperative complications. Results: A total of 1035 out of the 1100 patients returned the questionnaire, 94.1%. Overall the majority (65%) of patients had only mild pain at home; however, patients undergoing certain types of surgery had moderate-to-severe pain: inguinal hernia surgery (62% patients), orthopaedic surgery (41%), hand surgery (37%) and varicose vein surgery (36%). In these patients the severity of pain did not decrease during the 2-day study period. About 10% patients had more severe pain than they had anticipated, and 20% had difficulty in sleeping at night due to severe pain. Despite this, over 95% of patients were satisfied with man-agement of postoperative pain. Nausea (20%), tiredness (20%) and vomiting (8%) were the commonest complications reported during the first 48 h. A significant association was found between the administration of a general anaesthetic and the incidence of nausea postoperatively. A large number of patients were alone at home after the operation (28.4%); some (3.8%) had no access to a relative or friend in case of need. Conclusion: Our results show that about 35% of day-surgery patients experience moderate-to-severe pain at home in spite of analgesic medication. About 20% of patients had sleep problems due to severe pain. However, only 5% of patients were dissatisfied. Better analgesic techniques are necessary for patients undergoing certain types of surgery. Patient information and follow-up routines need to be improved.     

Cholecystokinin and neuropeptide Y receptors on single rabbit vagal afferent ganglion neurons: site of prejunctional modulation of visceral sensory neurons

A [¹²⁵I]cholecystokinin (CCK) analog and [¹²⁵I]peptide YY (PYY) were used to localize and characterize CCK and neuropeptide Y (NPY) receptor binding sites in the rabbit vagal afferent (nodose) ganglion. High concentrations of CCK and NPY binding sites were observed in 10.6% and 9.2% of the nodose ganglion neurons, respectively. Pharmacological experiments using CCK or NPY analogs suggest that both subtypes of CCK (CCK-A and CCK-B) and NPY (Y1 and Y2) receptor binding sites are expressed by discrete populations of neurons in the nodose ganglion. These results suggest sites at which CCK or NPY, released in either the nucleus of the solitary tract or a peripheral tissue, may modulate the release of neurotransmitters from a select population of visceral primary afferent neurons. Possible functions mediated by these receptors include modulation of satiety, opiate analgesia, and the development of morphine tolerance.     

地塞米松预防术后硬膜外吗啡镇痛的部分并发症

目的：观察静脉注射地塞米松（Dex)对减少手术后与硬膜外吗啡镇痛有关的部分并发症的发生率的作用。方法：随机双盲选择48例在硬膜外麻醉下行妇科肿瘤手术病人进行观察。所有病人在手术后均接受硬膜外吗啡镇痛。Dex组病人（n=24)在手术毕静注Dex8mg，对照组病人（n=24)则给予等量生理盐水。结果：在手术后24h内，Dex组病人手术后总的恶性呕吐发生率为16．7％，明显低于对照组病人的50％（P＜0．01）。两组病人手术后皮肤瘙痒的发生率无明显差异，镇痛效果也无明显差异。结论：预防性静脉注射Dex可减少术后硬膜外吗啡镇痛引起的恶心呕吐的发生率。