Tetrandrine potentiates caffeine-induced contraction but inhibits phenylephrine-induced contraction in perfused rat mesenteric artery

Effects of tetrandrine (TET), a bisbenzylisoquinoline alkaloid, on the contractile responses of perfused rat mesenteric arteries to phenylephrine (PE) and caffeine were investigated. TET concentration-dependently (1-30 micro M) attenuated phenylephrine-induced responses but potentiated the contractile responses to caffeine (5-40 mM) in the presence and absence of Ca(2+). Berbamine (BER), a structural analogue of TET, elicited a relatively smaller inhibitory effect on the responses to PE due to Ca(2+) release or Ca(2+) influx. However, both TET and BER elicited a comparable potentiating effect on caffeine-induced contraction. Cyclopiazonic acid (CPA; 10 micro M), a selective sarcoplasmic reticulum Ca(2+)-ATPase pump inhibitor, mimicked the potentiating effect of TET when added 5 min prior to caffeine in Ca(2+)-free medium. However, CPA did not augment and might even inhibit the caffeine-induced response when it was preincubated with the tissue for 25 min prior to the addition of caffeine. We propose that TET elicits differential effects on PE- and caffeine-induced responses in perfused rat mesenteric arterial bed. The inhibitory effect of TET on PE-induced responses is probably due to its direct interactions with alpha-adrenoceptors and PE-sensitive Ca(2+)-channels. The augmentation of caffeine-induced responses by TET, particularly in Ca(2+)-free medium, is likely to be due to its partial inhibition of the sarcoplasmic reticulum Ca(2+)-ATPase pump.     

Tetrandrine and related bis—benzylisoquinoline alkaloids from medicinal herbs：cardiovascular effects and mechanisms of action

Tetrandrine(TET),a bis-benzylisoquinoline alkaloid purified and identified an active ingredient in a Chinese medicinal herb,Radix Stephanae tetrandrae,has been used traditionally for the treatment of congestive circulatory disorder and inflammatory diseases.TET,together with a few of its structural analogues,has long been demonstrated to have antihypertensive action in clinical as well as animal studies.Presumably,the primary anti-hypertensive action of TET is due to its vasodilatory properties.TET prevents or inhibits vascular contraction induced by membrane depolarization with KCl or α-adrenoceptor activation with phenylephrine (PE).TET(30μmol/L) also inhibits the release of endothelium-derived nitric oxide(NO) as well as NO production by inducible NO synthase.TET apparently inhibits multiple Ca^2 entry pathways as demonstrated in cell types lacking the L-type Ca^2 channels.In cardiac muscle cells,TET inhibits both L-and T-type Ca^2 channels.In addition to its actions on cardiovascular tissues,TET may also exert its anti-hypertensive action via a Ca^2 -dependent manner on other tissues intimately involved in the modulation of blood pressure control,such as adrenal grands.In adrenal glomerulosa cells,KCl-or angiotensin II-induced aldosterone synthesis is highly dependent on extracellular Ca^2 .Steroidogenesis and Ca^2 -influx in bovine adrenal glomerulosa cells have been shown to be potently inhibited by TET.In bovine adrenal chromaffin cells,TET inhibits Ca^2 currents via L-and N-type channels as well as other unidentified channels with IC50 of 10μmol/L.Other than the Ca^2 antagonistic effects.TET also interacts with the α-adrenergic receptors and muscarinic receptors based on functional as well as radioligand binding studies.Apart from its functional effects,TET and related compounds also exert effects on tissue structures,such as remodelling of hypertrophied heart and inhibition of angiogenesis,probably by causing apoptotic responses.TET is also known for its anti-inflammatory and anti-fibrogenic actions,which make TET and related compound potentially useful in the treatment of lung silicosis,liver cirrhosis,and rheumatoid arthritis.     

毒性中药鬼臼质量标准研究

目的:建立毒性中药鬼臼的质量标准。方法:采用显微、液质联用方法进行定性鉴别,以液相色谱法进行含量测定。结果:各方法可用于鬼臼的质量鉴定。结论:建立的显微、LC-MS等方法可对其进行定性定量分析。     

Case report: A patient with primary biliary cirrhosis and autoimmune haemolytic anaemia

Diseases of an autoimmune nature are well recognized in association with primary biliary cirrhosis. Although autoimmune thyroiditis and many rheumatological conditions are well described in primary biliary cirrhosis, autoimmune haematological diseases have been less well reported. We report on a 66 year old North American Indian man with coincident primary biliary cirrhosis and warm antibody haemolytic anaemia. This case report supports the suggestion of an association between autoimmune haemolytic anaemia and primary biliary cirrhosis.     

New perspectives on vascular wall signaling: role of perivascular adipocytes and fibroblasts

This communication represents personal perspectives of recent development in the newly evolved areas in vascular signaling mechanisms at the anatomical level of vascular walls from outside in, that is, from perivascular adventitial side to effectuate the control of vascular reactivity. Since half a century ago, the focus of interest in vascular biology has been confined primarily to the study of the excitation-contraction coupling of vascular smooth muscle (VSM) as well as neuroeffector mechanisms. During the past 3 decades, considerable advancement in the understanding of vascular signaling has been made via the discovery of endothelium-derived relaxation factors (EDRF), endothelium-derived hyperpolarizing factors (EDHF) and endothelium-derived contracting factors (EDCF). The discovery of nitric oxide (NO) as a major cellular messenger has also helped open up another huge area of research in oxidative stress and vascular diseases. In the past decade, concepts on vascular wall signaling have been extended from vascular endothelial cells and then translated to the other seemingly inert cellular components, such as perivascular adipocytes and adventitial fibroblasts. Growing body of evidences show that these cellularities contribute to both functional as well as structural integrity in vasculature with significant pathophysiological implications.     

兰尼定对大鼠平滑肌细胞的肾上腺素能作用(英文)

电场刺激后释放的内源性去甲肾上腺素可引起大鼠输精管的双相收缩。初始的短暂收缩可被30μmol/L兰尼定和2μmol/L硝苯啶减弱,而后继的收缩部分可被2μmol/L硝苯啶消除,但被30μmol/L兰尼定增强。 外加的去甲肾上腺素也可产生输精管的双相收缩,这两相都能被2 μmol/L硝苯啶抑制,兰尼定30μmol/L可使两个相的收缩都减弱50％。我们推测兰尼定的结合位点在输精管的内质网。兰尼定对α-肾上腺素能刺激的不同相的作用不一致,表明对α-肾上腺素能的刺激一收缩偶合有两种方式。     

Association of interleukin-18 promoter polymorphism and atherosclerotic diseases in Chinese patients with diabetic nephropathy

Aim: Interleukin‐18 (IL‐18) is a pro‐inflammatory cytokine and possibly plays an important role in the pathogenesis of cardiovascular disease. The relationship between two IL‐18 gene polymorphisms, namely C‐607A and G‐137C, and cardiovascular disease in patients with diabetic nephropathy was examined. Methods: Two hundred and twenty patients (91 male) with diabetic nephropathy were studied. The IL‐18 promoter genotypes were determined. All patients were then prospectively followed for the cardiovascular events. Cardiovascular mortality and all‐cause mortality were also compared. Results: Mean age was 64.3 ± 10.6 years; average follow up was 73.9 ± 33.6 months. The frequencies of CC, CA and AA genotypes of the C‐607A polymorphism were 25.5%, 48.2% and 26.8%, respectively; GG, GC and CC genotypes of the G‐137C polymorphism were 71.8%, 25.0% and 3.2%, respectively. Neither of the polymorphisms were associated with the development of primary cardiovascular end‐point. Cardiovascular survival was 84.8% and 70.6% at 60 months for GG and GC/CC genotypes of the G‐137C polymorphism, respectively (P = 0.027); the corresponding actuarial survival was 69.0% and 54.8%, respectively (P = 0.053). However, the G‐137C genotype was not an independent predictor of cardiovascular or actuarial survival after adjusting for confounders by multivariate analysis with the Cox model. The C‐607A polymorphism had no significant effect on cardiovascular or actuarial survival. Conclusion: The G‐137C polymorphism of the IL‐18 promoter is associated with the cardiovascular mortality, and a trend of association with all‐cause mortality, in patients with diabetic nephropathy. The association, however, becomes insignificant after adjusting for confounding factors. Further studies are needed to test other genetic determinants of the association between systemic inflammation and cardiovascular disease in renal failure patients.