肾上腺髓质素对豚鼠心室肌细胞L-型钙通道的作用及其信号转导机制

目的: 研究肾上腺髓质素( adrenomedullin, ADM)抑制豚鼠心室肌细胞L-型钙通道的信号转导机制。方法: 应用全细胞膜片钳技术,记录应用ADM(1-100 nmol·L^-1)前后L-型钙电流(I_Ca,L),以及分别记录应用ADM特异性受体拮抗剂ADM_22-52(100 nmol·L^-1)+ADM(100 nmol·L^-1)、蛋白激酶A (PKA) 特异性拮抗剂H-89(10 μmol·L^-1) + ADM(100 nmol·L^-1)、蛋白激酶C (PKC) 特异性拮抗剂PKC_19-36(10 μmol·L^-1)+ADM(100 nmol·L^-1)、PKC特异性激动剂PMA(1 μmol·L^-1)前后I_Ca,L。结果: ADM(1-100 nmol·L^-1)浓度依赖性地抑制豚鼠心室肌细胞I_Ca,L,并可被ADM_22-52(100 nmol·L^-1)完全阻断;H-89(10 μmol·L^-1)对ADM抑制I_Ca,L的作用无影响。PKC_19-36(10 μmol·L^-1)可完全阻断ADM 对I_Ca,L的抑制效应,且PMA(1 μmol·L^-1)可模拟ADM 对I_Ca,L的抑制效应。结论: ADM作用于特异性ADM受体可浓度依赖性地抑制豚鼠心室肌细胞I_Ca,L,此作用有可能与PKC激活相关。     

Contribution of adrenomedullin to homeostatic response to cold stress in rat model

Acute stress known to stimulate sympathetic activity as well as the hypothalamo-pituitary–adrenal (HPA) axis, produces a significant increase in adrenomedullin (ADM) levels in the pituitary gland, plasma and adrenal glands, all of which are key components of HPA axis, suggesting a regulatory or protective role for ADM in countering HPA activation following a variety of physiological and psychological stressors. This study was conducted to assess a rat model for in depth investigation of biochemical mechanisms and consequences of cold stress. Four groups of Sprague–Dawley rats were observed for their serum total protein, glucose, trigliceride and cholesterol levels as well as their blood pressures after housing at room temperature, administration of ADM (1.0 nm/kg), exposing to cold stress (8 °C for 48 h) and exposing to ADM injection in addition to cold stress. The results suggest that application of ADM in addition to cold stress may act via receptors on different end-organs and causes altered metabolic regulation taking partial or total occupation of ADM receptors, stimulated in response to cold application induced physiologic ADM release before pharmacological ADM administration.     

肾上腺髓质素2对大鼠脑微血管内皮细胞增殖的影响

目的：研究肾上腺髓质素2（AM2）对大鼠脑微血管内皮细胞增殖的影响。 方法： 分离并培养SD大鼠脑微血管内皮细胞，经Ⅷ因子相关抗原的抗体鉴定和常规处理后，随机分为对照、AM2（10^-7 mol/L、10^-8 mol/L和10-9 mol/L）、ADM、ADM+AM2、10%胎牛血清和10％胎牛血清＋AM2 10-7 mol/L等8组，以［3H］-TdR掺入法测定MEC增殖反应。 结果： 10^-7-10^-9 mol/L各浓度AM2、ADM以及AM2和ADM合用对于静止状态的脑微血管内皮细胞［3H］-TdR掺入与对照组比较均无明显差异（均P>0.05）。10%胎牛血清刺激组脑微血管内皮细胞［3H］-TdR掺入比对照组高87.5%（P<0.05），10^-7mol/L AM2抑制胎牛血清诱导的脑微血管内皮细胞［3H］-TdR掺入增加（P<0.05）。 结论： AM2抑制血清诱导的脑微血管内皮细胞增殖。     

慢性支气管炎大鼠内皮素和肾上腺髓质素水平的变化及牛磺酸的作用

目的:探讨内皮素(endothelin,ET)和肾上腺髓质素(adrenomedullin,AdM)在慢性支气管炎大鼠血浆、支气管肺泡灌洗液(bronchoalveolarlavagefluid,BALF)和肺组织中含量的变化及牛磺酸的影响。方法:实验分为慢支组、牛磺酸组和对照组,每组6只大鼠。大鼠吸入含10-6(体积分数)二氧化硫的混合空气建立慢性支气管炎模型。放免法测定ET1和AdM含量。结果:血浆、BALF和肺组织ET1含量,慢性支气管炎动物比对照动物分别增加239%、243%和367%(P<0.01),牛磺酸组比慢支组分别降低31.7%、36.7%和62.6%(P值分别小于0.05、0.01和0.01)。血浆、BALF和肺组织AdM含量,慢支组大鼠比正常对照大鼠分别增加40%、100%和138%(P<0.01),牛磺酸组大鼠比慢支组分别减少18.6%、28.5%和29.5%(P值分别小于0.05、0.01和0.01)。结论:慢性支气管炎病程中ET1和AdM可能发挥一定作用;牛磺酸可能通过阻止ET1和AdM调节紊乱的发生发挥保护作用。     

影响大鼠主动脉肾上腺髓质素和肾上腺升压素释放的因素

用放射免疫法测定离体大鼠主动脉孵育或灌流介质中肾上腺髓质系（ＡＭ）和肾上腺升压素（ＡＴ）,发现：①～１００ｎｍｏｌ／Ｌ ＡＩＩ和ＥＴ－１呈剂量依赖性增加ＡＭ的释放率;１和１０ｎｍｏｌ／Ｌ ＡＩＩ和ＥＴ－１对ＡＴ的释放无明显的影响,１００ｎｍｏｌ／Ｌ ＡＩＩ和ＥＴ－１则增加ＡＴ释放率;这六组的ＡＭ／ＡＴ比值均增大;②１０ｎｍｏｌ／Ｌ肾上腺素增加ＡＭ和ＡＴ的释放率,１０ｎｍｏｌ／Ｌ ＣＧＲＰ则降低两者     

Direct cardiac and vascular actions of adrenomedullin in conscious sheep

1. Adrenomedullin (ADM) is a recently characterized circulating hormone which affects haemodynamic, renal and pituitary function in mammals. We have shown previously that in sheep, ADM produces vasodilatation together with increases in cardiac output and contractility. However, whether these effects are direct or mediated by autonomic reflexes is unclear. The present study examined the cardiovascular actions of an intravenous infusion of ADM in conscious, chronically instrumented sheep with either sympathetic, parasympathetic or autonomic ganglion blockade, to determine the role of the autonomic nervous system in mediating these cardiovascular changes.
2. Human ADM (1–52) was infused for 60 min at 2 μg kg⁻¹ h⁻¹ following: (1) saline control, (2) combined α/β-adrenoceptor (sympathetic) blockade (proporanolol 0.4 mg kg⁻¹ h⁻¹+phentolamine 0.15 mg kg⁻¹ h⁻¹ for 20 h), (3) muscarinic (parasympathetic) blockade (methscopolamine 0.05 mg kg⁻¹ h⁻¹ for 20 h) or (4) ganglion blockade (hexamethonium 3 mg kg⁻¹ h⁻¹ for 4 h). Measurements were made of mean arterial pressure (MAP), heart rate (HR), cardiac output (CO), stroke volume (SV), total peripheral conductance (TPC), maximal aortic flow (Fmax) and maximal rate of change of aortic flow (dF/dt).
3. ADM reduced MAP by 3±1 mmHg, and increased CO (1.2±0.2 l min⁻¹), HR (14±2 beats min⁻¹), TPC (21±3 ml min⁻¹ mmHg⁻¹), Fmax (2.3±0.8 l min⁻¹) and dF/dt (86±21 l min⁻¹ s⁻¹) in normal sheep. In animals with α/β blockade, similar changes were observed with ADM. However, during muscarinic blockade, the increases in HR (32±4 beats min⁻¹), CO (2.1±0.4 l min⁻¹), TPC (31±4 ml min⁻¹ mmHg⁻¹), Fmax (4.0±0.6 l min⁻¹), and dF/dt (150±12 l min⁻¹ s⁻¹) produced by ADM were enhanced. During ganglion blockade, ADM produced a greater reduction in MAP (−10±2 mmHg) compared to controls (−3±1 mmHg). However, there was no increase in HR. The changes in CO, TPC and contractility were similar to those observed in control animals.
4. These results suggest that the vasodilator effects of ADM on the periphery and its ability to increase CO and cardiac contractility are not mediated by the autonomic nervous system, but are probably the result of direct actions of ADM on the heart and vasculature.

     

C型利钠肽在慢性肺心病中的变化及临床意义

目的探讨C型利钠肽 (CNP)在慢性肺心病中的作用和临床意义。方法选择慢性肺源性心脏病 30例 ,分急性期和缓解期 (分别为B1和B2组 ) ,30例健康人为对照组 (A组 )。各组均采用放免法测定血浆CNP、肾上腺髓质素 (ADM )。结果临床实验组血浆CNP和ADM水平均高于正常对照组 (P <0 .0 1) ;血浆CNP水平B1高于B2 (P <0 .0 5 ) ;血浆ADM水平B1高于B2 (P <0 .0 1)。血浆CNP与血浆ADM水平呈正相关 (r=0 2 83,P <0 .0 5 )。结论CNP参与了慢性肺心病的病理生理过程 ;并且通过观察血浆CNP水平变化 ,可以反映肺心病的病情。     

肾上腺髓质素在肾上腺疾病中的免疫组化研究

目的：应用免疫组织化学技术观察免疫反应性肾上腺髓质素（ir-ADM)在人正常肾上腺、良恶性肾上腺肿瘤及肾上腺皮质增生组织中的分布特点。方法：对人正常肾上腺皮质（n＝10)和髓质（n=10)、嗜铬细胞瘤（n=31)、原发性醛固酮增多症的肾上腺皮质腺瘤（n=13)和增生（n=9)、皮质醇增多症的肾上腺皮质腺瘤（n=12)、增生（n=10)和腺癌（n=4)、无功能肾上腺皮质腺癌组织（n=7)进行ir-ADM的免疫组化染色。结果：10例人正常肾上腺髓质组织均显示ir-ADM染色阳性;31例嗜铬细胞瘤组织中16例染色阳性,大部分嗜铬细胞瘤组织中的ir-ADM免疫组化染色强度低于正常肾上腺髓质组织（P＜0．01）。在嗜铬细胞瘤中阵发性高血压组阳性染色例数多于持续性高血压组（P＜0．05）;人正常肾上腺皮质及各组皮质病变组织中,ir-ADM免疫组化染色均为阴性。结论：ir-ADM在嗜铬细胞瘤组织中分布呈不均一性,可能与嗜铬细胞瘤患者血压表现的多样化有关,应进一步探讨ADM在嗜铬细胞瘤发病中的病理生理作用。     

Adrenomedullin and adrenotensin regulate collagen synthesis and proliferation in pulmonary arterial smooth muscle cells

To understand the pathophysiological mechanisms of pulmonary arterial smooth muscle cell (PASMC) proliferation and extracellular-matrix accumulation in the development of pulmonary hypertension and remodeling, this study determined the effects of different doses of adrenomedullin (ADM) and adrenotensin (ADT) on PASMC proliferation and collagen synthesis. The objective was to investigate whether extracellular signal-regulated kinase (ERK1/2) signaling was involved in ADM- and ADT-stimulated proliferation of PASMCs in 4-week-old male Wistar rats (body weight: 100-150 g, n=10). The proliferation of PASMCs was examined by 5-bromo-2-deoxyuridine incorporation. A cell growth curve was generated by the Cell Counting Kit-8 method. Expression of collagen I, collagen III, and phosphorylated ERK1/2 (p-ERK1/2) was evaluated by immunofluorescence. The effects of different concentrations of ADM and ADT on collagen I, collagen III, and p-ERK1/2 protein expression were determined by immunoblotting. We also investigated the effect of PD98059 inhibition on the expression of p-ERK1/2 protein by immunoblotting. ADM dose-dependently decreased cell proliferation, whereas ADT dose-dependently increased it; and ADM and ADT inhibited each other with respect to their effects on the proliferation of PASMCs. Consistent with these results, the expression of collagen I, collagen III, and p-ERK1/2 in rat PASMCs decreased after exposure to ADM but was upregulated after exposure to ADT. PD98059 significantly inhibited the downregulation by ADM and the upregulation by ADT of p-ERK1/2 expression. We conclude that ADM inhibited, and ADT stimulated, ERK1/2 signaling in rat PASMCs to regulate cell proliferation and collagen expression.