鞘内注射左旋布比卡因下调甲醛炎性痛大鼠远位触液神经元P物质的表达

目的观察鞘内注射左旋布比卡因对甲醛炎性痛大鼠P物质(substanceP,SP)在脊髓背角及远位触液神经元(thedistal cerebrospinal fluid contacting neuron,dCSF-CN)表达的影响。方法采用CB-HRP大鼠侧脑室注射示踪标记dCSF-CN;48h后先鞘内注射0.5%左旋布比卡因10μl(并以鞘内注射10μl人工脑脊液作对照),大鼠左后掌足跖部皮下注射2.5%福尔马林建立炎性痛模型,记录大鼠舔足时间,1h后测定机械缩足阈值(mechanical withdrawal threshold,MWT)评估机械痛敏;免疫组织化学光镜镜检及免疫电镜镜检P物质在脊髓背角(L4~5)及dCSF-CN的表达。结果鞘内注射左旋布比卡因减少大鼠福尔马林试验的舔足时间(P<0.01),MWT值无变化(与基础值对比,P>0.05),SP在脊髓背角及dCSF-CN的表达弱于对照组(P<0.01)。结论鞘内注射左旋布比卡因减低脊髓伤害性疼痛反应及下调SP在dCSF-CN的表达。     

鞘内注射哌唑嗪对氯胺酮抗伤害作用的影响

目的　探讨脊髓α1 受体和氯胺酮(Ket, 37. 5mg·kg-1,ip)抗伤害作用的关系。方法　用热水甩尾法观察大鼠鞘内预先注射α1 受体拮抗剂哌唑嗪(Pra, 10, 30μg)对Ket抗伤害作用的影响。并用c fos基因免疫组织化学技术,观察Ket对痛刺激诱发的大鼠脊髓c- fos表达的调节作用及鞘内预先注射Pra(30μg)对Ket调节作用的影响。结果　鞘内单独注射各剂量Pra对动物痛阈均无明显影响(P>0 .05), 鞘内预注Pra(10μg)对Ket抗伤害作用无明显影响(P>0 .05)。而鞘内预注Pra(30μg)则可明显减弱Ket抗伤害作用(P<0 .05)。痛刺激前给予Ket明显减少背角各层Fos免疫阳性神经元的数量(P<0 .05),Ket对痛刺激诱发的脊髓ⅠⅣ层c fos表达的抑制作用可被鞘内预注Pra所减弱(P<0 .05)。结论　脊髓α1 受体参与Ket抗伤害作用。     

GABA_A受体部分介导丙泊酚在大鼠脊髓水平的抗伤害作用

目的研究丙泊酚在脊髓水平对大鼠伤害性感受的影响及GABAA受体在其中可能的作用。方法Sprague-Daw-ley(SD)♀大鼠随机分组,丙泊酚(Propofol,Pro)和荷包牡丹碱(B icucu lline,B ic)采用鞘内注射(ith)。行为学实验采用热板法和福尔马林实验,分别以舔后爪潜伏时间(Hot-p latelatency,HPL)和疼痛(累计)评分为指标。免疫组化方法观察丙泊酚鞘内给药对福尔马林单侧足底皮下注射诱发的脊髓背角Fos蛋白表达的影响。结果行为学部分:在两种疼痛模型中,鞘内注射丙泊酚(10 g.L-1)产生镇痛作用(P<0.01)。在热板法实验中,鞘内注射丙泊酚(10 g.L-1)产生的镇痛作用在10、20、30和40 min时间点可被鞘内给予Bic(0.01 g.L-1)分别拮抗81%、55%、81%和97%(均P<0.01)。在福尔马林实验中,鞘内注射丙泊酚(10 g.L-1)减少的福尔马林疼痛评分在30 min时间点可被Bic(0.01 g.L-1)相同部位注射拮抗67%(P<0.01)。免疫组化部分:鞘内注射丙泊酚(10 g.L-1)明显减少福尔马林单侧足底皮下注射引起的大鼠同侧腰段脊髓背角各层Fos免疫反应样神经元(Fos-like immunoreactivity,FLI)阳性细胞数(P<0.01);鞘内注射丙泊酚(10 g.L-1)产生的效应可被鞘内注射Bic(0.01 g.L-1)部分拮抗(P<0.01)。结论鞘内注射丙泊酚在大鼠可产生镇痛作用;GABAA受体部分介导了丙泊酚的以上作用。     

异氟烷催眠、镇痛作用与NMDA受体甘氨酸位点的关系

目的分析异氟烷催眠、镇痛作用与NMDA受体甘氨酸位点的关系。方法建立小鼠异氟烷注射催眠、镇痛模型后,在小鼠催醒、甩尾、福尔马林实验中,观察侧脑室或鞘内注射NMDA受体甘氨酸位点的激动剂D-丝氨酸(D-Serine,D-Ser)后小鼠睡眠时间、甩尾潜伏期或累计舔足时间的变化;用免疫组化方法观察异氟烷及鞘内用药对福尔马林小鼠脊髓Fos蛋白表达的影响。结果侧脑室注射D-Ser对异氟烷的催眠时间无影响(P>0.05)。鞘内注射D-Ser(0.025、0.05、0.1ng)可拮抗甩尾实验、福尔马林实验Ⅰ相中异氟烷的镇痛作用(P<0.05,P<0.01),而对福尔马林实验Ⅱ相异氟烷的镇痛作用无影响(P>0.05)。鞘内注射D-Ser0.05ng可拮抗异氟烷对福尔马林小鼠脊髓Fos蛋白表达的抑制作用(P<0.01)。结论异氟烷催眠作用与脑内NMDA受体甘氨酸位点关系不大;脊髓NMDA受体甘氨酸位点介导异氟烷对热、化学刺激的镇痛作用,而与异氟烷对慢性炎性疼痛的镇痛作用无明显关系。     

鞘内联合应用吗啡和氯胺酮对神经痛大鼠脊髓P物质表达的影响

目的研究鞘内联合应用吗啡和氯胺酮对神经痛大鼠脊髓P物质表达的影响。方法12只Wistar大鼠,体质量220~260 g,制备坐骨神经结扎模型并鞘内置管,随机分为4组(n=3):B组为空白对照组;C组鞘内注射生理盐水10μL;M组鞘内注射吗啡20μg;KM组鞘内注射吗啡10μg和氯胺酮25μg。坐骨神经结扎术后第4天开始鞘内给药,1次/d,连续7 d。用药7 d后处死大鼠,取腰段脊髓,免疫组化法测定脊髓P物质的含量。结果C组P物质表达明显低于B组(P<0.05)和KM组(P<0.01);KM组P物质表达明显高于M组(P<0.05)。结论鞘内联合应用吗啡和氯胺酮的抗伤害性作用,可能与其增加脊髓背角P物质的含量有关;脊髓背角P物质含量减少,可能介导慢性坐骨神经损伤后的痛敏持续状态。     

鞘内注射促皮质素抑制甲醛痛敏大鼠脊髓NOS阳性神经元增多

目的:研究鞘内注射促皮质素(Cor)对甲醛痛敏大鼠脊髓背角一氧化氮合酶(NOS)阳性神经元增多的影响。方法:采用痛级均数(PIR)测定、NADPH-d组织化学法、Fos免疫组织化学法染色,观察鞘内注射(ith)Cor对甲醛痛敏大鼠脊髓背角NOS阳性神经元、Fos免疫反应神经元、NOS/Fos双标记神经元及痛敏的影响。结果:ith Cor(0.5-1.5U)均能显著抑制甲醛引起的大鼠脊髓背角NOS、Fos、NOS/Fos阳性神经元的增多和痛敏反应,其作用为ith NOS底物左旋精氨酸(Arg,5-15nmol)部分翻转。结论:Cor通过抑制大鼠脊髓背角NOS阳性神经元的增多抑制痛敏。     

氧化槐定碱镇痛作用及其对小鼠中枢PKCγ表达的影响

目的研究氧化槐定碱(oxysophoridine,OSR)的镇痛作用及对小鼠脊髓背角、大脑皮层和丘脑蛋白激酶Cγ(Protein kinase C-γ,PKCγ)免疫阳性细胞的影响。方法用热板法观察并分析iv、icv途径给药后OSR镇痛作用强度及作用部位,免疫组织化学方法(SABC法)检测OSR对小鼠脊髓背角、大脑皮层和丘脑PKCγ免疫阳性细胞的影响。结果iv OSR 500、250、125mg·kg-1及icv OSR 100、50、25mg·kg-1均可延长小鼠热板反应舔足潜伏期(P<0.05、P<0.01),痛阈提高率分别为42.51%(iv)和60.70%(icv)。ip OSR 1000mg·kg-1可使小鼠脊髓背角、大脑皮层和丘脑PKCγ免疫阳性细胞明显减少(P<0.01)。结论OSR外周和中枢给药均有镇痛作用,PKCγ参与了OSR的镇痛作用。     

预先给予酪氨酸激酶抑制剂IPTRK3对神经源性疼痛的影响

目的探讨预先给予酪氨酸激酶(tyrosine kinase,Tr-kA)抑制剂IPTRK3对神经源性疼痛的抑制作用及其可能作用机制。方法建立小鼠坐骨神经部分结扎(partial sciaticnerve ligation,PSNL)模型,术前10 min单次腹腔给予IPTRK3 10 mg·kg-1,测定给药前后不同时间点小鼠的热痛觉过敏阈值(paw withdrawal latency,PWL)和机械痛觉过敏阈值(paw withdrawal threshold,PWT),免疫印迹法测量左侧L4-5背根神经节瞬时感受器电位香草酸受体1(transient re-ceptor potential vanilloid 1,TRPV1)的表达情况,免疫组织化学染色法测定Fos蛋白在L4-5脊髓背角的表达变化。结果与假手术(sham)组相比,PSNL组小鼠出现明显热、机械痛觉过敏(P<0.05),背根节TRPV1蛋白表达及脊髓背角Fos蛋白阳性神经元数目明显增多(P<0.05)。与PSNL组相比,预先给予IPTRK3 10 mg·kg-1明显减轻小鼠热痛觉过敏,背根神经节TRPV1蛋白表达水平及脊髓背角Fos蛋白阳性神经元数目明显降低(P<0.05),但仍明显高于sham组(P<0.05)。结论预先给予IPTRK3可以明显减轻神经源性疼痛症状,抑制背根神经节TRPV1及脊髓背角Fos蛋白的表达可能部分参与其早期迅速减轻伤害性刺激信息传递。     

鞘内注射氯胺酮对内脏痛大鼠远位触液神经元Fos蛋白表达的影响

目的观察鞘内注射氯胺酮对内脏痛大鼠远位触液神经元(dCSF-CN)Fos蛋白表达的影响。方法 SD大鼠侧脑室注射霍乱毒素亚单位B与辣根过氧化物酶复合物(CB-HRP)示踪标记dCSF-CN。48h后氯胺酮(K)组(n=10)鞘内注射氯胺酮50μg,人工脑脊液(C)组(n=10)鞘内注射等体积人工脑脊液。两组均在乙状结肠壁注射甲醛制作内脏痛模型。进行各时间点疼痛学评分,免疫组织化学法检测Fos蛋白在dCSF-CN中的表达。结果与C组相比,K组大鼠各时间点疼痛学评分降低(P<0.01),dCSF-CN中Fos蛋白表达下降(P<0.01)。K组未见CB-HRP/Fos双标记神经元。结论鞘内注射氯胺酮可以降低大鼠内脏痛反应,减少dCSF-CN中Fos蛋白的表达。     

GABA_A受体部分介导丙泊酚在中脑导水管周围灰质腹外侧区的致痛觉过敏作用

目的观察丙泊酚在vlPAG对大鼠伤害性感受的影响及GABAA受体在其中可能的作用。方法Sprague-Daw ley(SD)♀大鼠随机分组,丙泊酚(Propofol,Pro)和荷包牡丹碱(B icucu lline,B ic)采用中脑导水管周围灰质腹外侧区(ven-trolateral portion of the PAG,vlPAG)注射。行为学实验采用热板法和福尔马林实验,分别以舔后爪潜伏时间(Hot-p latelatency,HPL)和疼痛(累计)评分为指标。免疫组化方法观察丙泊酚在vlPAG对福尔马林单侧足底皮下注射诱发的脊髓背角Fos蛋白表达的影响。结果行为学部分:两种疼痛模型中丙泊酚(10 g.L-1)vlPAG注射引起痛敏(P<0.01)。热板法实验中,丙泊酚vlPAG微量注射的痛敏作用可被相同部位预先注射25 mg.L-1B ic在10和20 m in时间点分别拮抗70%和71%(均P<0.01),在30和40 m in完全拮抗。在福尔马林实验中,丙泊酚vlPAG微量注射使福尔马林疼痛评分增加,此作用可被B ic(25 mg.L-1)在60 m in拮抗57%(P<0.05)。免疫组化部分中,丙泊酚vlPAG微量注射使福尔马林引起的脊髓背角各层FLI阳性细胞数明显增多(P<0.01),B ic vlPAG微量注射(25 mg.L-1)可部分拮抗丙泊酚vlPAG微量注射的作用(P<0.01)。结论在大鼠vlPAG微量注射丙泊酚能产生痛敏作用;GABAA受体部分介导了丙泊酚的以上作用。     

NMDA受体介导皮下注射福尔马林诱发的大鼠脊髓Fos蛋白的表达

AIM: To examine the effects of N-methyl-D-aspartate (NMDA) and non-NMDA receptors on noxious stimulation-induced Fos expression in the rat spinal cord. METHODS: Formalin (2%) was injected s.c. into one hindpaw of the rat. Fos expression was exhibited by immunocytochemical technique. RESULTS: Two hours after s.c. formalin, Fos-like immunoreactive (FLI) neurons were distributed mainly in medial part of the lamina I and the outer lamina II of the ipsilateral dorsal horn. dl-2-Amino-5-phosphonovalerate (APV) administered intrathecally (10 microL, 0.01, 0.1, or 1 g.L-1) before injection of formalin into a hindpaw reduced the number of FLI neurons dose-dependently in the dorsal horn (P < 0.01), while 6,7-dinitroquinoxaline-2, 3(1H,4H)-dione (DNQX) (1 g.L-1) was ineffective. CONCLUSION: NMDA receptor mediated noxious stimulation-induced Fos expression in the rat spinal cord.     

在小鼠痛觉传导调节机制中的作用(英文)

目的 :研究组胺H3受体拮抗剂ciproxifan(CPF)在小鼠痛觉传导调节过程中的作用及其机制。方法 :用 3种不同的小鼠痛觉模型 (热板法、扭体法和福尔马林实验 )观察CPF的镇痛作用。同时用特异性组胺脱羧酶 (HDC)抑制药α 氟甲基组胺酸 (α FMH) ,观察组胺在CPF发挥镇痛效应过程中所起的作用。在福尔马林致痛模型中 ,还测定了小鼠脑、脊髓和血清中一氧化氮 (NO)和前列腺素E2(PGE2 )的含量。结果 :热板实验中 ,CPF 1mg·kg- 1和 3mg·kg- 1能明显延长小鼠的痛反应时间 ,其镇痛作用从用药后 2 0min开始 ,可持续 6 0min以上。扭体实验中 ,CPF 1mg·kg- 1可明显抑制小鼠的扭体次数 ,最高抑制率达 4 9.85 %。皮下注射福尔马林能引起 2个时相 (Ⅰ相、Ⅱ相 )的痛反应。这种由福尔马林引起的 2个时相的痛反应均可明显被CPF 0 .3,1,3mg·kg- 1抑制。在 3种致痛模型中 ,CPF的镇痛效应均可被α FMH 5 0mg·kg- 1逆转。使用福尔马林后 ,小鼠脑和脊髓中NO和PGE2 水平升高 ,而CPF能明显抑制这种升高作用 ,该抑制作用不被α FMH所拮抗。但CPF对血清中NO和PGE2 的浓度没有影响。结论 :组胺H3受体拮抗药CPF对多种性质刺激引起的疼痛均有镇痛作用 ,对福尔马林引起的炎性疼痛和非炎性疼痛都有效。CPF的这种镇痛作用可能与其促进?     

Modulation of formalin-induced behaviors and edema by local and systemic administration of dextromethorphan,memantine and ketamine

The present study examined the effects of local peripheral and systemic administration of three clinically used excitatory amino acid receptor antagonists (dextromethorphan, memantine, ketamine) on pain behaviors and edema produced by formalin (1.5% and 5%) in rats. Peripheral administration of dextromethorphan produced a locally mediated suppression of flinching behaviors induced by 1.5% and 5% formalin, but biting/licking behaviors were not affected. Memantine and ketamine had no effect on either of these behaviors. All three agents augmented edema produced by 1.5% and 5% formalin. When administered alone, dextromethorphan, memantine and ketamine produced an intrinsic paw swelling response, and this was blocked by the biogenic amine receptor antagonists mepyramine, phentolamine, methysergide and ketanserin. Following systemic administration, all three agents suppressed biting/licking behaviors, had no effect on flinching behaviors, and suppressed paw swelling induced by 5% formalin to varying degrees. These results provide evidence for a peripherally mediated antinociceptive action of dextromethorphan in the rat formalin test, but this may not necessarily be due to block of excitatory amino acid receptors as it is not observed with memantine or ketamine. All three agents produce a peripherally mediated paw swelling, which is likely due to blockade of biogenic amine reuptake. Systemic administration of all three agents produces antinociceptive and anti-inflammatory actions that may be due to block of excitatory amino acid receptors in the spinal cord.     

Evidence that inhibition of spinal nitric oxide production contributes to the antinociceptive effects of emulsified isoflurane on formalin-induced pain in rats

The aim of the present study was to investigate the contribution of spinal nitric oxide (NO) to the antinociceptive effects of emulsified isofluane in rats. The formalin test was used to assess nociceptive responses. Immunocytochemistry and histochemistry were performed to determine the effects of emulsified isoflurane on formalin-induced changes in Fos-like immunoreactive (Fos-LI)- and nicotinamide adenine dinucleotide phosphatediaphorase (NADPH-d)-positive neurons, respectively. The results showed that emulsified isofluane, administered intraperitoneally, significantly decreased the formalin-induced paw licking time and that this was attenuated by pretreatment with intrathecal injection of the NO precursor L-arginine. Furthermore, Fos-LI- and NADPH-d-positive neurons were mainly found in the ipsilateral dorsal horn after injection of formalin, some of which were Fos-LI/NADPH-d double-labelled neurons. Administration of emulsified isofluane significantly decreased Fos-LI- and NADPH-d-positive, as well as Fos-LI/NADPH-d double-labelled, neurons. Finally, emulsified isofluane produced a significant reduction of NOS activity and a decrease of NO production in the spinal cord of formalin-treated rats. In conclusion, the results suggest that inhibition of spinal NO production contributes to the antinociceptive effects of emulsified isofluane on formalin-induced pain in rats.     

Antinociceptive effects of methysergide in various pain models

Several studies have demonstrated that the nonselective opioid receptor antagonist naloxone produces a paradoxical antinociception in the formalin test. The opioid system is related to the serotonergic system for producing antinociception at the spinal level. Here we also asked whether systemic (i.p.) and intrathecal (i.t.) administrations of a nonselective serotonergic antagonist, methysergide, might produce paradoxical antinociception similar to naloxone in the mouse formalin test. A diluted formalin solution was injected into the mouse plantar region of the hind paw and the duration of licking responses was measured at periods of 0-5 min (1st phase) and 20-40 min (2nd phase) after formalin injection. Methysergide administered i.p. and i.t. showed an attenuated licking duration only in the 2nd phase. The effect observed in the 2nd phase was reversed in the 5,7-dihydroxytriptamine, but not N-(2-chloroethyl)-N-ethyl-2-bromobenzylamine pretreated group of mice, suggesting that descending serotonergic, but not noradrenergic, systems are involved in the methysergide antinociception. To further investigate the mechanism by which methysergide inhibited the nociceptive behaviors induced by formalin, the antinociceptive effect of methysergide was also tested in substance P (i.t.) and excitatory amino acids (i.t.), such as glutamate, N-methyl-D-aspartic acid, alpha-amino-3-hydroxy-5-methylisoxazole-4-propionic acid, and kainic acid, which are major components in the formalin-induced nociceptive transmission in the spinal cord pain models. The duration of nociceptive behaviors shown in these models was significantly shortened by i.p. and i.t. administration of methysergide. These results suggest that methysergide also produces a paradoxical antinociception in various pain models including the formalin test, similar to the results of naloxone.     

Effects of Intrathecal Injection of Nicotine on the Analgesic Effects of Isoflurane in a Model of Inflammatory Pain

Abstract: The present study was designed to investigate the role of spinal neuronal nicotinic acetylcholine receptors in the analgesic effects of isoflurane. After having established the mice model of analgesia by intraperitoneally injecting (i.p.) appropriate doses of isoflurane, nicotine, a neuronal nicotinic acetylcholine receptor agonist was intrathecally injected. The effects of isoflurane and nicotine on paw licking times and formalin‐induced c‐fos expression in the spinal cord dorsal horn were examined. Our correlative studies have shown that isoflurane can decrease the paw licking times and simultaneously suppress c‐fos expression after injection of formalin in the mice. Nicotine can partially antagonize the effects induced by isoflurane above. Spinal neuronal nicotinic acetylcholine receptors may be important targets for the analgesic effects of isoflurane in formalin pain.     

The capsaicin test in mice for evaluating tachykinin antagonists in the spinal cord

A capsaicin test involving peripheral nociception, which produces behaviour similar to that elicited by formalin, is described in mice. Capsaicin was injected subcutaneously (s.c.) into the dorsal surface of a hindpaw and the time the animals spent licking the paw was recorded. Doses of capsaicin of 6.25–1600 ng induced nociception, during a period of 5 min, starting immediately after injection and disappearing completely at 10 min. Intrathecally (i.t.) administered [ -Arg¹, -Trp^7,9, Leu¹¹]substance P (spantide), a tachykinin antagonist and [ -Phe⁷, -His⁹]substance P (6–11), a selective antagonist of substance P (SP), inhibited the capsaicin-induced behaviour, in a dose-dependent manner. This licking behaviour was also inhibited by intrathecal administration of SP antiserum but not by somatostatin (SOM) antiserum. Intrathecal pretreatment with capsaicin resulted in a marked reduction of the licking response, following subcutaneous injection of capsaicin into the paw. Capsaicin-induced licking was not affected by intrathecal administration of cyclo[7-aminoheptanoyl-Phe- -Trp-Lys-(OBz)-Thr], a SOM antagonist and by intrathecal pretreatment with cysteamine, a SOM depletor. This nociceptive test may allow discrimination between SP- and SOM-mediated responses in the spinal cord of the mouse.     

Local Antinociceptive and Hyper algesic Effects in the Formalin Test after Peripheral Administration of Adenosine Analogues in Mice

Abstract: Adenosine administered to humans has been reported to induce pain after intravenous administration. On the other hand adenosine analogues have been shown to possess antinociceptive effects after peripheral and intrathecal administration in animals. The aim of the present study was to investigate the effect of peripheral administration of adenosine agonists with different affinities for the A1 and A2 adenosine receptors on a persistent pain stimulus using the formalin test. The drugs chosen were, R-phenylisopropyl-adenosine (R-PIA) with high affinity for the A1 receptor, N-ethylcarboxamide-adenosine (NECA) with almost equal affinity for the A1 and A2 receptor and 2-(2-aminoethylamino)-carbonylethylphenylethylamino-adenosine (APEC) with high affinity for the A2 receptor. The drugs were mixed with formalin and administered subcutaneously into the dorsal hind paw in mice to study the local effects. They were also injected separately from the formalin solution in different paws to evaluate the systemic effect. The total time of licking the injected paw during the first 5 min. was recorded. In high doses all compounds reduced the licking activity, but a low dose of APEC (1 μM) injected together with the formalin solution had an algesic effect. All effects were antagonized by theophylline. These results suggests that A1 adenosine receptors mediate a local peripheral antinociceptive effect and the involvement of local peripheral A2 receptors in the enhancement of the algesic response.