鱼腥草注射液过敏及类过敏实验研究

目的 评价鱼腥草注射液及其辅料吐温80(Tween-80)静脉给药的致敏性。方法 采用Beagle犬类过敏及过敏实验,观察给药后动物行为变化和检测血浆中组胺、IgE、IgM、IgG的含量。结果 含有Tween-80的鱼腥草注射液及Tween-80组动物给药后出现显著的行为异常,血浆组胺升高,而IgE变化不规律,IgG、IgM则无明显改变。结论 鱼腥草注射液中导致犬严重类过敏反应与Tween-80有关。建议Beagle犬的过敏及类过敏试验,应作为中药注射液致敏试验的必做实验,行为异常及血浆中组胺为主要的判定指标,IgE作为辅助判定指标。     

鱼腥草注射液新制剂致敏性评价实验研究

目的:采用Beagle犬致敏实验研究来评价鱼腥草注射液新制剂(new Houttuynia Cordata injec-tion,NYI)的致敏性。方法:在类过敏和过敏试验中,通过静脉注射不同剂量的NYI,观察给药后Beagle犬的行为学变化,检测血浆中组胺、IgE的含量变化。结果:NYI在致敏给药后未出现明显的行为异常,类过敏试验中血浆组胺和IgE升高不明显,在过敏试验中血浆组胺和IgE未见升高。结论:NYI对Beagle犬未发现有明显的过敏性反应,为临床安全用药提供了实验依据。     

三种注射用新辅料对Beagle犬类过敏及过敏反应研究

目的研究3种注射用新辅料乙交酯-丙交酯共聚物（PLGA）、乙二醇单甲醚-聚乳酸嵌段共聚物（mPEG-PDLLA）和羟丙基-β-环糊精（HP-β-CD）能否引起Beagle犬产生类过敏或过敏反应,为临床研究和应用提供依据。方法使用Beagle犬于1、3、5d致敏共3次,末次致敏后第14d激发。观察给药后反应症状,检测常规血液学指标、血浆中组胺、IgE、IgG和IgM含量。结果上述各项指标在首次给药后和激发日激发后均未见明显异常改变。结论 PLGA、mPEG-PDLLA和HP-β-CD在本实验剂量下不能引起Beagle犬产生类过敏或过敏反应。     

鱼腥草蒸馏液与3种增溶剂配伍后对Beagle犬的致敏性

目的:比较聚山梨酯-80(吐温-80)、泊洛沙姆188和羟丙基-β-环糊精(HP-β-CD)3种增溶剂对Beagle犬的致敏性.方法:3种增溶剂分别与鱼腥草蒸馏液配伍,采用主动全身过敏试验的方法对Beagle犬静脉给药,观察给药后犬的过敏反应、体温变化、心电图变化以及血常规、肝肾功、血清组胺和总IgE的变化情况.实验同时设鱼腥草蒸馏液单独给药对照组.结果:1%吐温-80组的犬给药后均出现3级以上过敏反应,伴有心率加快,血清组胺水平明显升高.其余3组犬均未出现明显不良反应,且给药前后血清组胺水平没有明显变化.结论:泊洛沙姆188和HP-β-CD与鱼腥草蒸馏液配伍对Beagle犬的致敏性明显低于吐温-80.     

含聚山梨酯80中药注射剂对Beagle犬致敏性研究

目的：选择5种含聚山梨酯80（Tween 80）的中药注射剂进行Beagle犬致敏性试验,探讨聚山梨酯80对5种注射剂对Beagle犬致敏性的影响。方法：在类过敏和过敏试验中,通过静脉恒速注射各种中药注射剂,观察Beagle犬的症状变化,检测血浆中组胺、免疫球蛋白E（immunoglobulin E,IgE）、免疫球蛋白G（immunoglobulin,IgG）和免疫球蛋白M（immunoglobulin M,IgM）含量。结果：5种含聚山梨酯80的中药注射剂均呈现Beagle犬类过敏和过敏反应阳性或强阳性。结论：聚山梨酯80与含聚山梨酯80中药注射剂发生严重不良反应相关,今后应谨慎使用。     

鱼腥草注射液中过敏原成分

目的探索鱼腥草注射液中的过敏原成分及其致敏机理。方法分别用鱼腥草注射液、鱼腥草蒸馏液、吐温80、阴性对照物和阳性对照物对豚鼠和Brown Norway(BN)大鼠进行全身主动过敏试验,并用吐温80首次静脉注射豚鼠和BN大鼠进行类过敏试验。观察其行为学反应并检测动物血清中组胺、IL-4、IgE、IgG和IgM的水平。结果阳性对照组、鱼腥草注射液组、吐温80组和鱼腥草蒸馏液组动物都观察到不同程度的行为学过敏反应,且动物血清中的组胺、IgE和IL-4水平,以及阳性对照组和吐温80组的BN大鼠血清中IgM水平与阴性对照组相比显著性升高,IgG、IgM及鱼腥草蒸馏液组BN大鼠血清中组胺和IL-4水平无显著变化。吐温80类过敏试验组,动物的行为学及血清中各生化指标均未见显著变化。结论吐温80为鱼腥草注射液中的主要过敏原,可以引起豚鼠和BN大鼠发生Ⅰ型全身主动过敏反应,而不引起豚鼠和BN大鼠发生类过敏反应。鱼腥草蒸馏液中含有其他引起过敏反应的过敏原。     

7种中药注射剂对Beagle犬类过敏反应研究

 目的：选择临床报告过敏性休克排名较前的7种中药注射剂进行Beagle犬类过敏反应试验（anaphylactoid reaction）,并探讨聚山梨酯80（Tween 80）对中药注射剂致敏性的影响。方法：通过一次静脉恒速注射各种中药注射剂,观察Beagle犬的反应症状,检测血浆中组胺、免疫球蛋白E （immunoglobulin E,IgE）、免疫球蛋白G（immunoglobulin,IgG）和免疫球蛋白M （immunoglobulin M,IgM）含量。结果：根据行为症状和组胺含量升高综合判断为类过敏反应强阳性者有含Tween 80的鱼腥草、脉络宁和复方丹参注射剂,其他为阳性。结论：7种中药注射剂均出现类过敏反应,吐温80是导致含Tween 80的中药注射剂类过敏反应的主要诱因之一,但非惟一原因,尚存在一些其他诱发物质,需进一步研究。     

鱼腥草注射液的被动皮肤过敏试验及体外过敏试验

目的探索鱼腥草注射液中的过敏原及其致敏机制,并建立药物过敏原筛选的方法。方法分别用鱼腥草注射液、鱼腥草蒸馏液、吐温80、阴性对照物和阳性对照物对BALB/C小鼠、SD大鼠进行异种被动皮肤过敏试验,并对RBL-2H3细胞进行体外致敏试验。检测BALB/C小鼠和BN大鼠抗血清中IgE的含量、被动皮肤过敏反应中大鼠蓝斑直径大小及体外致敏实验中肥大细胞的脱颗粒反应。结果鱼腥草注射液A组、鱼腥草注射液B组、吐温80组、鱼腥草蒸馏液组和阳性对照组的BALB/C小鼠和BN大鼠血清中的IgE水平均显著升高。当BALB/C小鼠抗血清稀释比例为1∶2时,SD大鼠被动皮肤过敏反应均呈阳性;BALB/C小鼠抗血清稀释比例为1∶8时,仅鱼腥草注射液B组和阳性对照组SD大鼠呈阳性;BALB/C小鼠抗血清稀释比例为1∶32时,各组SD大鼠均未见阳性。体外过敏试验结果显示:鱼腥草注射液组、吐温80组、鱼腥草蒸馏液组和阳性对照组的肥大细胞脱颗粒百分率、β-氨基己糖苷酶释放率和上清中组胺释放量,与阴性对照组相比均有显著性增加。结论吐温80为鱼腥草注射液的主要过敏原,其致敏机制是由IgE介导的,经过吐温80的首次致敏和二次激发出现有细胞因子及炎性介质参与的机体异常的免疫调节,引起一系列过敏症状。鱼腥草蒸馏液中含有其他引起过敏反应的过敏原。体外过敏试验结果与动物试验结果一致,体外致敏模型可用于药物过敏原的筛选。     

血塞通注射液致动物急性过敏反应研究

目的探讨血塞通注射液引起的急性过敏反应的机制。方法采用ELISA法测定给药后豚鼠、小鼠血清中IgE及组胺的含量变化,同时观察其过敏行为的变化,判断急性过敏反应的类型,采用显微观察血塞通注射液引起肥大细胞脱颗粒情况。结果血塞通注射液给药后引起豚鼠、小鼠的IgE及组胺升高,血塞通注射液引起小鼠的过敏及过敏样反应行为较豚鼠明显。血塞通注射液可引起致敏后及未致敏的肥大细胞脱颗粒。结论血塞通注射液引起的急性过敏反应为过敏样反应及I型过敏反应,目前中国药典采用的豚鼠评价模型对于评价注射液的过敏样反应有待商榷。     

RNAⅢ抑制肽的急性毒性和全身主动过敏实验

摘要：目的:观察RNAⅢ抑制肽衍生物RIP1183对SD大鼠、Beagle犬的急性毒性反应和对豚鼠过敏反应。方法:SD大鼠和Beagle犬随机分为RIP1183给药组和对照组。SD大鼠尾静脉注射RIP1183,单次剂量为50 mg·kg-1,间隔4～5 h,连续2次总剂量为100 mg·kg-1,对照组给予等体积的0.9%氯化钠注射液,给药后连续14 d观察RIP1183对大鼠的毒性作用。Beagle犬静脉注射RIP1183,最大给药剂量为50 mg·kg-1,对照组给予等体积的0.9%氯化钠注射液,给药后连续14 d观察RIP1183对Beagle犬的体质量、体温、摄食量、血清生化指标、血液学指标、眼科检查和心电图的影响。采用豚鼠全身主动过敏实验,Hartley豚鼠随机分为阴性对照组（0.9%氯化钠注射液）、阳性对照组（牛血清白蛋白V）、RIP1183低(9.3 mg·kg-1、高(18.6 mg·kg-1)剂量组,每组6只。动物致敏腹腔注射给药3次,激发静脉注射给药2次,激发给药后观察动物是否出现过敏反应。结果:给予RIP1183后,SD大鼠外观、行为活动、饮食等均未见明显异常,体质量增长正常,结束时全部存活,大体解剖未见肉眼可见变化。Beagle犬给药后,其体质量、体温和摄食量与对照组比较差异无统计学意义（P>0.05）,其他各项指标均无异常。阳性对照组豚鼠在激发后出现过敏症状,RIP1183各剂量组豚鼠激发后未见明显异常和过敏反应症状。结论:SD大鼠和Beagle犬分别静脉给予100 mg·kg-1和50 mg·kg-1?RIP1183后均无异常反应亦无死亡;豚鼠的RIP1183过敏反应为阴性。     

Beneficial effect of arginine vasopressin on hemorrhagic shock through improving the vascular reactivity

The vascular reactivity and calcium sensitivity were decreased following hemorrhagic shock. Arginine vasopressin (AVP) was beneficial to endotoxic, infectious/spetic and hemorrhagic shock. Our previous studies found that Rho kinase played an important role in the occurrence of calcium desensitization following shock. It was reported that AVP was with stimulation effect of Rho kinase. So we hypothesized that AVP might have beneficial effect on shock via activation of Rho kinase to regulate the calcium sensitivity and vascular reactivity. Hemorrhagic shock (40 mmHg for 2 h) Wistar rats in vivo were adopted to observe the effects of small dose of AVP on hemodynamics, 24-h survival rate, the pressor effect of norepinephrine (NE) and the contractility of superior mesenteric artery (SMA). Isolated SMAs from hemorrhagic shock rats were adopted to observe the effects of AVP on vascular reactivity and calcium sensitivity and its relationship to Rho kinase with an isolated organ perfusion system. The results show that AVP at the concentration of 0.1 U/kg and 0.4 U/kg significantly improved the hemodynamic parameters and the 24-h survival rate of hemorrhagic shock rats. Meanwhile, these dosages of AVP significantly increased the pressor effect of NE and the contractile response of SMA to NE. Y-27632 (3 μg/kg), a Rho kinase specific inhibitor, abolished the beneficial effects of AVP. In vitro, the calcium sensitivity and vascular reactivity of SMA to calcium and NE were significantly decreased following hemorrhagic shock. AVP at the concentration of 0.5 nmol/L and 5 nmol/L significantly increased the calcium sensitivity and vascular reactivity. These effects of AVP were abolished by Y-27632 (10 μmol/L). Taken together, the results suggest that AVP at 0.1 U/kg and 0.4 U/kg is beneficial to hemorrhagic shock by improving the vascular reactivity, which involves activation of Rho kinase.     

Rac对失血性休克大鼠血管反应性的调节作用

目的探讨Rac在失血性休克大鼠血管反应性调节中的作用。方法采用SD大鼠复制休克模型,取离体血管环,观察休克早期和晚期血管反应性的变化以及Rac激动剂和特异性抑制剂对休克早期和晚期血管反应性的影响;通过酶消化法培养原代血管平滑肌细胞（vascular smoot hmuscle cell,VSMC）,采用双室培养方式分别观察VSMC缺氧10min和90min后VSMC对去甲肾上腺素（norepinephrine,NE）的收缩反应性变化,同时观察Rac活性调节剂对缺氧后VSMC收缩反应性的影响。结果在休克早期和短暂缺氧后,离体血管环和VSMC对NE收缩反应性均有所升高,Rac的激动剂血小板衍生生长因子（platelet derived growth factor,PDGF）可部分降低休克早期或短暂缺氧后血管反应性,Rac特异性抑制剂NSC23766可拮抗由PDGF所引起的血管反应性的变化,而在休克晚期或长时间缺氧后,离体血管环和VSMC对NE收缩反应性明显降低,NSC23766对休克晚期或长时间缺氧所致血管反应性降低有升高作用。结论休克后血管反应性呈双相变化,休克早期升高,休克晚期降低,Rac参与了休克血管反应性的调节。     

Pinacidil pretreatment improves vascular reactivity after shock through PKCα and PKCε in rats

We investigated the beneficial effect of pinacidil pretreatment on vascular reactivity, calcium sensitivity, and animal survival after hemorrhagic shock, its relationship to protein kinase Cα (PKCα), protein kinase Cε (PKCε), and adenosine. Using hemorrhagic shock rats, the protective effects of different extents of pinacidil pretreatment on vascular reactivity and in which the roles of PKCα, PKCε, and adenosine were observed. Pinacidil pretreatment significantly improved shock-induced decrease of vascular reactivity of superior mesenteric artery, which was antagonized by the PKCα antagonist G?-6976 (5 × 10 mole/L) and PKCε pseudosubstrate inhibitory peptide (1 × 10 mole/L). Pinacidil pretreatment induced the translocation of PKCα and PKCε from the cytoplasm to the membrane. This translocation of PKCα and PKCε was eliminated by adenosine A1 receptor antagonist DPCPX (1 × 10 mole/L). As compared with simple fluid resuscitation, combination with pinacidil pretreatment significantly improved the vascular reactivity and survival rate of hemorrhagic-shocked rats. These results suggested that pinacidil pretreatment could induce good protective effects on vascular reactivity and calcium sensitivity after hemorrhagic shock mainly through the activation of PKCα and PKCε via adenosine A1 receptor, and this protective effect made an important contribution to the overall outcome of shock therapy.     

肌内皮缝隙连接在失血性休克大鼠内皮依赖和非内皮依赖的血管舒/缩功能调节中的作用

目的 研究肌内皮缝隙连接(myo-endothelial gap junction,MEGJ)通道在失血性休克大鼠肠系膜上动脉血管(SMA)的内皮依赖和非内皮依赖的血管收缩/舒张功能调节中的作用.方法 利用在体血管管径测定技术,观察MEGJ的阻断剂18α-甘草次酸(18α-GA)对非内皮依赖的血管收缩剂去甲肾上腺素(N...     

Effects of MCI-154 on vascular reactivity and its mechanisms after hemorrhagic shock in rats

The objectives of this study were to investigate the effects of 6-[4-(4'-pyridylamino)phenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride trihydrate (MCI-154), a newly developed cardiotonic agent, on vascular reactivity and contractile responses to extracellular Ca2+ ([Ca2+]o) after hemorrhagic shock and primarily explore its mechanism. In vivo, the effects of MCI-154 (0.1, 0.5, 1.0, and 2.0 mg/kg) on the pressor effect of norepinephrine (NE) in rats subjected to hemorrhagic shock (30 mm Hg for 2 h) were observed and in vitro, the effects of MCI-154 (10(-7), 10(-6), 10(-5), 10(-4) mol/L) on vascular reactivity and contractile responses to [Ca2+]o of superior mesenteric artery (SMA) from hemorrhagic shock rats and its relationship to Rho-kinase, protein kinase C (PKC), and protein kinase G (PKG) were observed. The results showed that the NE-induced pressor response after hemorrhagic shock was significantly decreased (P<0.01), and MCI-154 made it decrease further. In vitro, MCI-154 further decreased the contractile responses of SMA to NE and Ca2+ after hemorrhagic shock as compared with untreated hemorrhagic shock group (P<0.01). Angiotensin II (Ang II), with Rho-kinase stimulating action, and PMA, a PKC agonist increased the contractile responses to [Ca2+]o of SMA after hemorrhagic shock. MCI-154 (10(-5) mol/L) partly inhibited Ang II and PMA-induced increase of the contractile responses to [Ca2+]o of SMA (P<0.01). KT-5823, the PKG antagonist, antagonized MCI-154-induced decrease of the contractile responses to [Ca2+]o. Taken together, these results suggested that the vascular reactivity and contractile responses to [Ca2+]o of vascular smooth muscle after hemorrhagic shock were significantly decreased. MCI-154 worsened hemorrhagic shock-induced vascular hyporeactivity and the decrease of contractile responses to [Ca2+]o. These effects were possibly regulated by Rho-kinase, PKC, and PKG, but this needs further confirmation.     

Effects of ischemic preconditioning on vascular reactivity and calcium sensitivity after hemorrhagic shock and their relationship to the RhoA–Rho-kinase pathway in rats

We investigated the effect of ischemic preconditioning (IPC) on vascular reactivity and calcium sensitivity after hemorrhagic shock and its relationship to the RhoA–Rho-kinase pathway. Using hemorrhagic-shock rats (40 mm Hg for 3 hours) and isolated rings of the superior mesenteric artery (SMA), the effects of IPC (abdominal aorta occlusion applied 2 hours before shock) on the pressor effect of norepinephrine (3 μg/kg), vascular reactivity and calcium sensitivity of SMA, and the activity and role of RhoA and Rho-kinase were investigated. IPC with 1-minute occlusion plus 5-minute loosening of aneurysm clips thrice significantly increased survival time and prevalence of survival at 24 hours of hemorrhagic-shock rats. This IPC condition also significantly increased the pressor response of norepinephrine and significantly improved the vascular reactivity and calcium sensitivity of the SMA. The activity of Rho-kinase and RhoA in the SMA decreased after hemorrhagic shock, but increased after IPC. Y-27632 (Rho-kinase antagonist) and C3 Transferase (RhoA antagonist) significantly decreased IPC-induced increase in vascular reactivity and calcium sensitivity. These results suggested that IPC can improve shock-induced vascular hyporeactivity and calcium desensitization. The RhoA–Rho-kinase pathway played an important part in this process. These findings suggested that the RhoA–Rho-kinase pathway may be a potential target to treat vascular hyporeactivity in severe trauma, shock, or multiple-organ dysfunction syndrome.     

Ryanodine receptor 2 contributes to hemorrhagic shock-induced bi-phasic vascular reactivity in rats

Aim:

Ryanodine receptor 2 (RyR2) is a critical component of intracellular Ca²⁺ signaling in vascular smooth muscle cells (VSMCs). The aim of this study was to investigate the role of RyR2 in abnormal vascular reactivity after hemorrhagic shock in rats.

Methods:

SD rats were hemorrhaged and maintained mean arterial pressure (MAP) at 40 mmHg for 30 min or 2 h, and then superior mesenteric arteries (SMA) rings were prepared to measure the vascular reactivity. In other experiments, SMA rings of normal rats and rat VSMCs were exposed to a hypoxic medium for 10 min or 3 h. SMA rings of normal rats and VSMCs were transfected with siRNA against RyR2. Intracellular Ca²⁺ release in VSMCs was assessed using Fura-2/AM.

Results:

The vascular reactivity of the SMA rings from hemorrhagic rats was significantly increased in the early stage (30 min), but decreased in the late stage (2 h) of hemorrhagic shock. Similar results were observed in the SMA rings exposed to hypoxia for 10 min or 3 h. The enhanced vascular reactivity of the SMA rings exposed to hypoxia for 10 min was partly attenuated by transfection with RyR2 siRNA, whereas the blunted vascular reactivity of the SMA rings exposed to hypoxia for 3 h was partly restored by transfection with RyR2 siRNA. Treatment with the RyR agonist caffeine (1 mmol/L) significantly increased Ca²⁺ release in VSMCs exposed to hypoxia for 10 min or 3 h, which was partially antagonized by transfection with RyR2 siRNA.

Conclusion:

RyR2-mediated Ca²⁺ release contributes to the development of bi-phasic vascular reactivity induced by hemorrhagic shock or hypoxia.     

Tie-2介导Ang-1、Ang-2调节大鼠失血性休克血管反应性双相变化的作用研究

目的 观察Tie-2在血管生成素-1(angiopoietin-1, Ang-1)、血管生成素-2(angiopoietin-2, Ang-2)调节失血性休克血管反应性双相变化中的作用。方法 采用离体微血管环张力测定技术和western blot技术,观察失血性休克后不同时间点肠系膜上动脉(superior mesenteric artery,SMA)中Tie-2蛋白表达和磷酸化变化、抑制Tie-2对Ang-1和Ang-2调节缺氧早期和晚期血管反应性作用的影响,以及给予Ang-1和Ang-2后缺氧的血管内皮细胞(vascular endothelial cell, VEC)和血管平滑肌细胞(vascular smooth muscle cell, VSMC)混合细胞中Tie-2蛋白表达和磷酸化变化,并观察抑制Tie-2对缺氧早期和晚期的混合细胞NO含量的影响。结果 (1) 肠系膜上动脉Tie-2蛋白表达和酪氨酸磷酸化在正常时很低,失血性休克后逐渐增高,在休克早期(休克10min),Tie-2蛋白表达变化不大,但酪氨酸磷酸化已明显增高(P<0.01);随着休克时间延长,Tie-2蛋白表达和酪氨酸磷酸化均进一步显著增高(P<0.01)。(2)Tie-2抑制剂可降低缺氧10min的血管高反应性(NE的Emax由13.479mN降低至10.122mN,P<0.05),并显著抑制Ang-1对缺氧10min血管反应性的维持作用(Emax由15.283mN降低至10.253mN,P<0.01);Tie-2抑制剂可改善缺氧4h的血管低反应性(NE的Emax由5.875mN增高至8.003mN,P<0.05),并显著拮抗Ang-2进一步降低缺氧4h血管反应性的作用(Emax由3.444mN增高至7.643mN,P<0.01)。(3)缺氧10min时,降低血管高反应性的Ang-2可降低Tie-2磷酸化,使其由0.0403降低至0.0123(P<0.01);缺氧4h时,恢复血管低反应性的Ang-1可降低Tie-2蛋白表达,使其由0.2276降低至0.0851 (P<0.01),也可以降低Tie-2磷酸化,使其由0.1437降低至0.0359 (P<0.01)。(4) NO含量在缺氧早期显著增高,Ang-2和Tie-2抑制剂显著抑制其增高(P<0.01);缺氧晚期NO含量较正常对照组增高得更为显著,Ang-1和Tie-2抑制剂可抑制其增高(P<0.01)。结论 Ang-1、Ang-2通过Tie-2受体调节大鼠失血性休克血管反应性双相变化。     

Stimulation of the adenosine A3 receptor reverses vascular hyporeactivity after hemorrhagic shock in rats

Aim:

To investigate whether adenosine A₃ receptors (A₃AR) stimulation restore vascular reactivity after hemorrhagic shock through a ryanodine receptor (RyR)-mediated and large conductance calcium-activated potassium (BK_Ca) channel-dependent pathway.

Methods:

Rat hemorrhagic shock model (40 mmHg) and vascular smooth muscle cell (VSMC) hypoxic model were used. The expression of A₃AR was determined by Western blot and RT-PCR. The effect of A₃AR stimulation on RyR-mediated Ca²⁺ release in VSMCs was analyzed by the Fura-3/AM loading Ca²⁺ imaging. The modulation of vascular reactivity to norepinephrine (NE) by A₃AR stimulation was monitored by an isolated organ tension instrument.

Results:

Decrease of A₃AR expression is consistent with the loss of vasoreactivity to NE in hemorrhagic shock rats. The stimulation of A₃AR with a selective agonist, IB-MECA, could partly but significantly restore the vasoreactivity in the rats, and this restorative effect could be counteracted by MRS1523, a selective A₃AR antagonist. In hypoxic VSMCs, RyR activation by caffeine significantly evoked the rise of [Ca²⁺] compared with the control cells, a phenomenon closely associated with the development of vascular hyporeactivity in hemorrhagic shock rats. The stimulation of A₃AR with IB-MECA significantly blocked this over activation of RyR-mediated Ca²⁺ release. RyR activation by caffeine and BK_Ca channel activation by NS1619 attenuated the restoration of vasoreactivity to NE resulting from A₃AR stimulation by IB-MECA after hemorrhagic shock; this attenuation effect could be antagonized by a selective BK_Ca channel blocker.

Conclusion:

These findings suggest that A₃AR is involved in the modulation of vasoreactivity after hemorrhagic shock and that stimulation of A₃AR can restore the decreased vasoreactivity to NE through a RyR-mediated, BK_Ca channel-dependent signal pathway.     

Modulation of Ca2+ channels by opioid receptor antagonists in mesenteric arterial smooth muscle cells of rats in hemorrhagic shock

The effects of hemorrhagic shock on Ba currents ( ) via Ca channels and the regulation of the channels in the vascular hyporesponse stage of hemorrhagic shock by opioid receptor antagonists were examined by using the whole-cell recording of patch-clamp technique in mesenteric arterial smooth muscle cells of rats. The results showed that hemorrhagic shock induced an inhibition of Ca channels in the cells; 10 micro M of naloxone and 100 n of naltrindole, nor-binaltorphimine, and beta-funaltrexamine increased the in the cells of rats in shock. After inhibition of protein kinase C by using 1-(5-isoquindinesulfonyl)-2-methylpiperazine via electrodes, the enhancement of by the antagonists was not observed. These results suggested that the inhibition of Ca channel induced by hemorrhagic shock was mediated by delta-, kappa-, and mu -opioid receptors in the cells and may be partly responsible for vascular hyporesponse. The enhancement of was mediated by activation of protein kinase C and may be responsible for the antagonist-caused improvement in the response of resistance arteries to vasoactive stimulants at the decompensatory stage of hemorrhagic shock.