缺血预适应心肌保护作用的神经递质调节

缺血预适应是指心脏遭受短暂缺血后能耐受随后较长时间缺血损伤,是近年发现的一种预防心肌缺血损伤的有效措施。缺血预适应的心肌保护作用是心脏释放内源性心血管活性物质所介导。神经递质（儿茶酚胺、乙酸胆碱、降钙素基因相关肽、阿片肽等）可能是介导缺血预适应的内源性心肌保护物质。外源性应用神经递质能模拟缺血预适应的心肌保护作用。神经递质可同其它内源性活性物质相互作用。神经递质介导缺血预适应可能是通过与其相应受体结合,触发细胞内信息转导途径,激活蛋白激酶C产生心肌保护作用。     

缺血预适应的研究现状和前景

缺血预适应是一种内源性保护机理 ,即短暂缺血后能耐受随后较长时间的缺血损伤 ,这一现象已在不同种属动物和临床病人中得到证实 .缺血预适应表现为早期和延迟心肌保护 .缺血预适应的信号转导途径涉及触发物质 (内源性活性物质 ) ,中介物质 (蛋白激酶 )和效应物质 (离子通道和保护蛋白 ) .核因子 - κB可能在心肌缺血预适应的延迟保护中起重要作用 .缺血预适应已扩展到药理性预适应 ,单磷酯 A,尼可地尔等能显著减轻心肌缺血损伤 .     

降钙素基因相关肽在前列腺素介导豚鼠心脏缺血预适应中的作用(英文)

目的:研究降钙素基因相关肽与前列腺素在豚鼠心脏缺血预适应中的相互作用。方法:采用Langen-dorff方法灌注豚鼠离体心脏。记录心率、冠脉流量、左室内压以及最大变化速率,并测定冠脉流出液中降钙素基因相关肽(CGRP)与6-酮-PGF_(1α)的释放量。结果:内皮素-1(200 pmoL)引起心功能下降,表现为冠脉流量、心率、左室内压及其最大变化速率降低。缺血预适应可明显减轻内皮素-1引起的心脏损伤,同时预适应期间CGRP与6-酮-PGF_(1α)的释放量明显增加。应用辣椒素耗竭内源性CGRP后,缺血预适应的保护作用被取消。选择性CGRP_1受体拮抗剂CGRP_(8-37)100nmol/L也能取消缺血预适应的保护作用。环氧化酶抑制剂吲哚美辛(10μmol/L)可取消缺血预适应的保护作用,同时缺血预适应促进CGRP与6-酮-PGF_(1α)释放的作用也被取消。结论:前列腺素参与了缺血预适应对豚鼠心脏的保护作用,前列腺素的作用是由CGRP所介导。     

心肌缺血预适应及其产生机制

心肌缺血预适应是指短暂的心肌缺血再灌注能显著减轻长时间心肌缺血再灌注损伤。这种保护作用表现在缩小心肌梗死范围、抗缺血再灌注心律失常、改善心肌的收缩和舒张功能等。心肌缺血预适应的机制与内源性心脏保护物质的释放以及膜受体信号传导通路有关。1心肌缺血预适应的提出     

内源性阿片肽介导大鼠后肢缺血预适应的保护作用

研究了内源性阿片肽介导大鼠后肢缺血预适应的保护作用. 后肢缺血2 h，乙酰胆碱（ACh）诱导的血管内皮依赖性舒张性反应明显下降. 缺血预适应（缺血5 min，再灌5 min，重复3 次）能显著减弱长时间缺血对ACh舒血管效应的抑制作用，这种保护作用可被纳洛酮（3 mg·kg^-1）取消. 预先给予吗啡（300 μg·kg^-1）也能产生与缺血预适应相同的血管内皮保护作用. 然而，预先用辣椒素（50 mg·kg^-1）耗竭降钙素基因相关肽后，吗啡的保护作用被取消. 结果提示，内源性阿片肽介导大鼠后肢缺血预适应的血管保护作用，其机理可能涉及内源性降钙素基因相关肽.     

降钙素基因相关肽在一氧化氮介导热应激诱导心肌延迟预适应中的作用

目的：研究一氧化氮－降钙素基因相关肽途径是否参与热应激诱导的心肌延迟预适应。方法：采用Langendorff装置灌注离体心脏。心脏低温（4℃）保存4h后,再灌注40min(37℃）。实验前24h大鼠进行高温处理（直肠温度42℃,15min)。记录心率,冠脉流量、左室内压以及最大变化速率,并测定血浆降钙素基因相关肽（CGRP）浓度和冠脉流出液中肌酸激酶（CK）释放量。结果：热应激能显著增强心肌停搏液的保护作用,减少CK释放量,并升高血浆CGRP浓度。这些作用能被预先给予亚硝基精氨酸甲酯及辣椒素所取消。结论：一氧化氮参与了对大鼠心脏的延迟保护,其作用是由内源性CGRP所介导。     

Protection of ischemic preconditioning mediated by endogenous opioid peptides in rat hindquarters

研究了内源性阿片肽介导大鼠后肢缺血预适应的保护作用．后肢缺血２ｈ，乙酰胆碱（ＡＣｈ）诱导的血管内皮依赖性舒张性反应明显下降．缺血预适应（缺血５ｍｉｎ，再灌５ｍｉｎ，重复３次）能显著减弱长时间缺血对ＡＣｈ舒血管效应的抑制作用，这种保护作用可被纳洛酮（３ｍｇ·ｋｇ－１）取消．预先给予吗啡（３００μｇ·ｋｇ－１）也能产生与缺血预适应相同的血管内皮保护作用．然而，预先用辣椒素（５０ｍｇ·ｋｇ－１）耗竭降钙素基因相关肽后，吗啡的保护作用被取消．结果提示，内源性阿片肽介导大鼠后肢缺血预适应的血管保护作用，其机理可能涉及内源性降钙素基因相关肽．     

辣椒辣素对大鼠再灌注损伤的心肌早期和延迟保护作用(英文)

目的:研究辣椒辣素预处理的早期和延迟心肌保护。方法:采用Langendorff装置灌注离体心脏,记录心率、冠脉流量、左室内压以及最大变化速率,并测定降钙素基因相关肽(CGRP)的血浆浓度及灌注液中肌酸激酶(CK)的释放量。结果:辣椒辣素(50mg·kg~(-1),sc)改善心功能、降低CK释放,并升高CGRP的血浆浓度。预先用辣椒辣素耗竭感觉神经递质后,辣椒辣素的心肌保护和升高CGRP血浆浓度作用消失,应用辣椒辣素24h或48h后,其对缺血心肌仍具有保护作用。结论:辣椒辣素能诱导早期和延迟心肌保护,其保护作用可能与促进CGRP释放有关。     

Mediation of calcitonin gene-related peptide in protection of ischemic preconditioning in rat hindlimbs

目的：研究降钙素基因相关肽（ＣＧＲＰ）介导缺血预适应对血管内皮的保护．方法：大鼠后肢缺血２ｈ后，观察乙酰胆碱诱导血管内皮依赖性舒张反应．结果：缺血不影响去甲肾上腺素的缩血管效应，但能显著削弱乙酰胆碱的舒血管效应．缺血预适应能阻止长时间缺血对乙酰胆碱舒血管效应的抑制作用，这种保护作用可被反复应用辣椒素耗竭ＣＧＲＰ所取消．急性应用辣椒素促进ＣＧＲＰ释放或外源性应用ＣＧＲＰ均可产生预适应样的保护作用．结论：大鼠后肢缺血预适应对内皮细胞的保护与辣椒素敏感的感觉神经有关；ＣＧＲＰ能模拟缺血预适应保护血管．     

吴茱萸次碱对心脏过敏损伤的保护作用

目的 观察吴茱萸次碱对心脏过敏损伤的保护作用与激活辣椒素受体。剌激内源性降钙素基因相关肽(CGRP)释放的关系。方法 预致敏的离体心脏用K-H液恒压逆行灌流,从侧管中注入牛血清白蛋白(5 mg),造成过敏损伤。测定冠脉流出液中CGRP和心肌组织中肿瘤坏死因子(TNF-α)的浓度。结果预致敏的豚鼠心脏受抗原(牛血清蛋白)攻击引起冠脉流量(CF)显著减少,左室内压(LVP)和左室内压最大变化速率(±dp/dtmax)降低,同时伴有心率(HR)的增加和P-R间期的延长。两个浓度吴莱萸次碱(0.3或1.0 μmol·L-1)均能显著抑制抗原攻击所致的心功能抑制,表现为LVP、±dp/dtmax和CF升高,P-R间期明显缩短,并能同时促进CGRP的释放和降低心肌组织TNF-α的浓度。昊茱萸次碱对窦性心动过速无明显影响。吴茱萸次碱对心脏过敏损伤的保护作用能被一种选择性CGRP受体拮抗剂CGRP8-37所取消。结论 吴茱萸次碱对心脏过敏损伤的保护作用是通过促进CGRP释放所介导,其心脏保护作用可能与抑制心肌组织TNF-α产生有关。     

Delayed cardioprotection by intestinal preconditioning is mediated by calcitonin gene-related peptide

Previous studies have shown that nitric oxide and calcitonin gene-related peptide (CGRP) are involved in mediation of the delayed cardioprotection of ischemic or pharmacological preconditioning, and nitric oxide can evoke the release of CGRP. In the present study, we examined the role of CGRP in nitric oxide-mediated delayed cardioprotection by brief intestinal ischemia in rats. The serum concentration of creatine kinase and infarct size were measured after 45-min coronary artery occlusion and 180-min reperfusion. Ischemic preconditioning was induced by six cycles of 4-min ischemia and 4-min reperfusion of the small intestine. Pretreatment with intestinal ischemic preconditioning for 24, 48, or 72 h significantly reduced infarct size and creatine kinase release, and the effects of ischemic preconditioning were completely abolished by L-nitroarginine methyl ester (L-NAME, 10 mg/kg, i.p.), an inhibitor of nitric oxide synthase, or by pretreatment with capsaicin (50 mg/kg, s.c.), which selectively depletes transmitters in capsaicin-sensitive sensory nerves. Intestinal preconditioning caused a significant increase in plasma concentrations of CGRP, and the effect was also abolished by L-NAME or capsaicin. These results suggest that the delayed cardioprotection afforded by intestinal ischemic preconditioning is mediated by endogenous CGRP via the nitric oxide pathway.     

The cardioprotective effects of nitroglycerin-induced preconditioning are mediated by calcitonin gene-related peptide

Previous investigations have shown that endogenous calcitonin gene-related peptide (CGRP) may play an important role in the mediation of ischemic preconditioning and that nitroglycerin evokes the release of CGRP. In the present study, we examined whether nitroglycerin provides a preconditioning stimulus, and whether the cardioprotective effects of nitroglycerin-induced preconditioning involve endogenous CGRP. Thirty minutes of global ischemia and 30 min of reperfusion caused a significant impairment of cardiac contractile function and an increased release of creatine kinase. Pretreatment with nitroglycerin at the concentration of 3x10(-7) or 10(-6) M for 5 min produced a significant improvement of cardiac function and a decrease in the release of creatine kinase. The content of CGRP-like immunoreactivity in coronary effluent was increased during nitroglycerin perfusion. However, the cardioprotection afforded by nitroglycerin was abolished by CGRP-(8-37) (10(-7) M), a selective CGRP receptor antagonist. Pretreatment with capsaicin (50 mg/kg, s.c.), which specifically depletes the transmitter content of sensory nerves, also abolished the protective effects of nitroglycerin and markedly reduced the release of CGRP from the heart during nitroglycerin perfusion. These findings suggest that nitroglycerin-induced preconditioning is related to stimulation of CGRP release in rat hearts.     

The cardioprotection of calcitonin gene-related peptide-mediated preconditioning

Preconditioning induced by brief ischemia or hyperthermia or some drugs shows two phases, early and delayed protection. The cardioprotection afforded by preconditioning is related to stimulation of endogenous mediators release. Calcitonin gene-related peptide (CGRP), a major transmitter of capsaicin-sensitive sensory nerves, has recently been shown to play an important role in mediation of the preconditioning induced by brief ischemia or hyperthermia or by some drugs, and alpha-CGRP seems to play a major role in the mediation of delayed preconditioning. It has been shown that the cardioprotection afforded by CGRP-mediated preconditioning is due to inhibition of cardiac tumor necrosis factor-alpha (TNF-alpha) production, but not to the activation of the K(ATP) channel.     

Delayed preconditioning by cardiac ischemia involves endogenous calcitonin gene-related peptide via the nitric oxide pathway

Previous investigations have shown separately that calcitonin gene-related peptide (CGRP) or nitric oxide (NO) is involved in mediation of ischemic preconditioning. In the present study, we tested interactions of CGRP with NO in mediation of delayed preconditioning. In Sprague-Dawley rats, ischemia-reperfusion injury was induced by 45-min occlusion followed by 3-h reperfusion of coronary artery, and preconditioning was induced by four cycles of 3-min ischemia and 5-min reperfusion. Infarct size, plasma creatine kinase activity, the plasma level of NO and CGRP, and the expression of CGRP mRNA in dorsal root ganglion were measured. Pretreatment with preconditioning significantly reduced infarct size and the release of creatine kinase during reperfusion, and caused a significant increase in the expression of CGRP mRNA, concomitantly with an elevation in the plasma level of CGRP and NO. The effects of preconditioning were completely abolished by administration of L-nitroarginine methyl ester (L-NAME, 10 mg/kg, i.p.), an inhibitor of NO synthase. Pretreatment with capsaicin (50 mg/kg, s.c.), which depletes transmitters in capsaicin-sensitive sensory nerves, also blocked the cardioprotection of preconditioning and reduced the synthesis and release of CGRP, but did not affect the concentration of NO. The present results suggest the delayed protection afforded by ischemic preconditioning is also mediated by endogenous CGRP via the NO pathway in rat heart.     

The role of calcitonin gene-related peptide (CGRP) in ischemic preconditioning in isolated rat hearts

Brief coronary artery occlusion can protect the heart against damage during subsequent prolonged coronary artery occlusion; ischemic preconditioning. The role of calcitonin gene-related peptide (CGRP) in ischemic preconditioning is investigated in isolated perfused rat hearts, by measuring CGRP release during ischemic preconditioning and mimicking this by exogenous CGRP infusion, either in the absence or presence of the CGRP antagonist BIBN4096BS. CGRP increased left ventricular pressure and coronary flow in a concentration dependent manner, which was effectively antagonized by BIBN4096BS. Rat hearts (n=36) were subjected to 45 min coronary artery occlusion and 180 min reperfusion, which was preceded by: (1) sham pretreatment, (2) BIBN4096BS infusion (1 microM), (3) preconditioning by 15 min coronary artery occlusion and10 min reperfusion, (4) as 3, but with BIBN4096BS, (5) 15 min CGRP infusion (5 nM) and 10 min washout, (6) as 5, but with BIBN4096BS. Cardiac protection was assessed by reactive hyperaemia, creatine kinase release, infarct size related to the area at risk (%), and left ventricular pressure recovery. Preconditioning increased CGRP release into the coronary effluent from 88+/-13 to 154+/-32 pg/min/g, and significantly protected the hearts by decreasing reactive hyperaemia (35%), reducing creatine kinase release (53%), limiting infarct size (48%), and improving left ventricular pressure recovery (36%). Exogenous CGRP induced preconditioning-like cardioprotection. BIBN completely abolished the cardioprotection induced by preconditioning as well as by exogenous CGRP. In conclusion, since cardioprotection of preconditioning-induced CGRP release can be mimicked by exogenous CGRP, and both can be blocked by a CGRP antagonist, results indicate an important role for CGRP in ischemic preconditioning.     

Protection of calcitonin gene-related peptide-mediated preconditioning against lysophosphatidylcholine-induced myocardial injury in isolated rat hearts

研究心脏缺血预适应（ＰＣ）对溶血性磷脂酰胆碱（ＬＰＣ）损伤心肌作用的影响，并探讨降钙素基因相关肽（ＣＧＲＰ）在ＰＣ中的作用．离体大鼠心脏Ｌａｎｇｅｎｄｏｒｆ法灌流，记录心率，冠脉流量，左室压和左室压最大上升速率（＋ｄｐ／ｄｔｍａｘ），并测定灌流液中肌酸磷酸激酶（ＣＰＫ）含量．结果显示，ＬＰＣ能降低各项心功能指标，并使ＣＰＫ释放增加；ＰＣ（缺血５ｍｉｎ，再灌５ｍｉｎ，重复３次）能减轻ＬＰＣ的损伤作用；ＰＣ的心肌保护作用可被选择性ＣＧＲＰ受体拮抗剂ＣＧＲＰ８－３７所取消；预先给予ＣＧＲＰ或辣椒素能产生与ＰＣ相同的心肌保护作用．对照组，ＬＰＣ，ＰＣ＋ＬＰＣ，ＣＧＲＰ８－３７，ＣＧＲＰ８－３７＋ＰＣ＋ＬＰＣ，ＣＧＲＰ＋ＬＰＣ，ＣＧＲＰ８－３７＋ＣＧＲＰ＋ＬＰＣ，辣椒素＋ＬＰＣ组ＣＰＫ释放量分别为０．２６±０．０５，２．３０±０．２２，０．２５±０．０３，０．３０±０．０８，２．６０±０．１５，０．２４±０．０５，２．７０±０．２０和０．２５±０．０７μｍｏｌ·ｍｉｎ－１·ｇ－１湿组织．这些结果提示：１）ＰＣ对ＬＰＣ所致心肌损伤具有保护作用；２）ＰＣ的保护作用是由ＣＧＲＰ所介导；３）ＣＧＲＰ或辣椒素可模拟ＰＣ的保护作?     

降钙素基因相关肽介导缺血预适应对溶血性磷脂酰胆碱损伤心肌的保护作用

研究心脏缺血预适应(PC)对溶血性磷脂酰胆碱(LPC)损伤心肌作用的影响，并探讨降钙素基因相关肽(CGRP)在PC中的作用. 离体大鼠心脏Langendorff法灌流，记录心率，冠脉流量，左室压和左室压最大上升速率(+dp/dt_max)，并测定灌流液中肌酸磷酸激酶(CPK)含量. 结果显示，LPC能降低各项心功能指标，并使CPK释放增加；PC(缺血5 min， 再灌5min，重复3次)能减轻LPC的损伤作用；PC的心肌保护作用可被选择性CGRP受体拮抗剂CGRP_8-37所取消；预先给予CGRP或辣椒素能产生与PC相同的心肌保护作用. 对照组, LPC, PC+LPC, CGRP_8-37, CGRP_8-37+PC+LPC, CGRP+LPC, CGRP_8-37+CGRP+LPC, 辣椒素+LPC组CPK释放量分别为0.26±0.05, 2.30±0.22, 0.25±0.03, 0.30±0.08, 2.60±0.15, 0.24±0.05, 2.70±0.20和0.25±0.07 μmol·min^-1·g^-1湿组织. 这些结果提示：1) PC对LPC所致心肌损伤具有保护作用；2) PC的保护作用是由CGRP所介导；3) CGRP或辣椒素可模拟PC的保护作用.     

Inhibition of cardiac tumor necrosis factor-alpha production by calcitonin gene-related peptide-mediated ischemic preconditioning in isolated rat hearts

Previous investigations have demonstrated that calcitonin gene-related peptide (CGRP) plays an important role in the mediation of ischemic preconditioning in rats. In the present study, we examined signal transduction pathways of CGRP-mediated ischemic preconditioning. Thirty minutes of global ischemia and 40 min of reperfusion caused a dramatic decrease in myocardial function, and a significant increase in the release of cardiac creatine kinase in the coronary effluent and in the content of tumor necrosis factor-alpha (TNF-alpha) in myocardial tissues. However, ischemic preconditioning (three cycles of 5-min ischemia and 5-min reperfusion) or pretreatment with CGRP for 5 min dramatically improved the recovery of cardiac function, and reduced the release of cardiac creatine kinase and the TNF-alpha content. The effect of ischemic preconditioning was abolished by CGRP-(8-37), the selective CGRP receptor antagonist, and by capsaicin, which depletes sensory nerve neurotransmitter content, but was unaltered by treatment with glibenclamide, a blocker of the ATP-sensitive potassium (K(ATP)) channel. The protective effects of exogenous CGRP-induced preconditioning were also not blocked by glibenclamide. These results suggest that the cardioprotective effects afforded by CGRP-mediated ischemic preconditioning are related to inhibition of cardiac TNF-alpha production, but not to activation of the K(ATP) channel.     

Monophosphoryl lipid A-induced delayed preconditioning is mediated by calcitonin gene-related peptide

The delayed preconditioning of the heart by monophosphoryl lipid A is mediated by endogenous nitric oxide (NO), and the cardioprotection afforded by nitroglycerin is related to stimulation of calcitonin gene-related peptide (CGRP) release. The objective of this study was to explore whether improvement of preservation with cardioplegia by monophosphoryl lipid A is mediated by CGRP. In addition, we examined the effect of monophosphoryl lipid A on the tumor necrosis factor-alpha (TNF-alpha) content of myocardial tissues. The isolated rat heart was perfused in the Langendorff mode. Heart rate, coronary flow, left-ventricular pressure, and its first derivatives (+/-dp/dt(max)) were recorded, and plasma levels of NO and CGRP, the release of creatine kinase in coronary effluent and the content of TNF-alpha in myocardial tissues were measured. Hypothermic ischemia for 4 h caused a decline in cardiac function, and an increase in the release of creatine kinase and in the content of TNF-alpha. Pretreatment with monophosphoryl lipid A (500 microg/kg, i.p.) for 24 h improved the recovery of cardiac function and reduced the release of creatine kinase concomitantly with a decrease in the content of cardiac TNF-alpha. Monophosphoryl lipid A markedly increased plasma concentrations of CGRP and NO. After pretreatment with L-nitroarginine methyl ester (L-NAME), the cardioprotection and the increased release of NO and CGRP induced by monophosphoryl lipid A were abolished. Capsaicin also abolished the cardioprotection and the increased release of CGRP induced by monophosphoryl lipid A, but did not affect the content of NO. The results suggest that monophosphoryl lipid A-induced preconditioning enhances preservation with cardioplegia and that the protective effects of monophosphoryl lipid A are related to stimulation of CGRP release.