Effect of phentolamine on myocardial extracellular matrix of cardiac remodeling in rats

Objective:To study the effects of phentolamine on myocardial extracellular matrix of cardiac remodeling induced by norepinephrine in rats.Methods:24 SD rats were divided into 3 groups randomly:control groups,norepinephrine groups(model groups),norepinephrine +phentolamine groups(treatment groups).Echocardiography was used to detect changes in cardiac structure and function,the level of collagen volume fraction(CVF) and hydroxy-proline as well as collagen content were determined in myocardial tissue,matrix metalloproteinases-2 and collagen Ⅰin myocardial tissue were localized by immunohistochemitry.Results:Compared with control groups,left ventricular hypertrophy in the model group rats,the livdioxyproline content and CVF was significantly higher(P<0.01),and matrix metalloproteinase- 2 and collagen Ⅰ protein expression was significantly increased(P<0.01).Phentolamine significantly improved cardiac hypertrophy in treatment group rats,reduced hydroxy-proline,CVF,matrix metalloproteinase 2and collagen Ⅰ protein expression(P<0.05).Conclusions:Phentolamine can effectively reduce the incidence of myocardial hypertrophy and myocardial extracellular matrix remodeling in SD rats,and it can ease myocardial extracellular matrix of cardiac remodeling.It may he associated with reduced expression of matrix metalloproteinase 2 and collagen Ⅰ in myocardial tissue remodeling.

Effects of Phentolamine on Hemorrheology and Hemodynamics in Dogs with Acute Liver Damage

The effects of phentolamine on hemorrheology and hemodynamics were studied in dogs with acute liver damage induced by acetaminophen. After 1 h of phentolamine application , the viscosity of plasma and whole blood was significantly diminished. The hematocrit readings followed the same pattern as the alterations in viscosity. The portal venous resistance and the value of K were remarkably decreased and the portal venous blood flow was obviously increased. It can be assumed , therefore , that the decrease in viscosity induced by phentolamine results from internal hemodilution and phentolamine may improve hepatic blood circulation through the decrease of portal venous resistance caused by the reduction of blood viscosity and the dilation of portal vascular beds.

Curative effect of silybin combined with pituitrin-phentolamine for pulmonary tuberculosis complicated by acute hemoptysis

Objective: To study the curative effect of silybin combined with pituitrin-phentolamine for pulmonary tuberculosis complicated by acute hemoptysis. Methods: A total of 78 patients with pulmonary tuberculosis complicated by acute hemoptysis who were treated in this hospital between December 2013 and April 2017 were divided into control group (n=39) and silybin group (n=39) by random number table. Control group received pituitrin-phentolamine hemostasis therapy, silybin group received pituitrin-phentolamine combined with silybin therapy, both were treated for 1 week. The differences in peripheral blood liver function and coagulation index levels as well as serum oxidative stress index contents were compared between the two groups of patients before treatment and after 1 week of treatment. Results:Before treatment, the differences in peripheral blood liver function and coagulation index levels as well as serum oxidative stress index contents were not statistically significant between the two groups. After 1 week of treatment, peripheral blood liver function indexes ALT, AST, ALP and STB contents of silybin group were lower than those of control group;peripheral blood coagulation indexes PT, APTT and TT levels were lower than those of control group whereas Fib level was higher than that of control group;serum oxidative stress indexes AOPPs and LHP contents were lower than those of control group whereas GSH-Px and T-AOC contents were higher than those of control group. Conclusion: pituitrin-phentolamine combined with silybin therapy can effectively protect the liver function, optimize the coagulation function and reduce the oxidative stress response in patients with pulmonary tuberculosis complicated by acute hemoptysis.

Arterial relaxation is coupled to inhibition of mitochondrial fission in arterial smooth muscle cells:comparison of vasorelaxant effects of verapamil and phentolamine

Mitochondria are morphologically dynamic organelles which undergo fission and fusion processes. Our previous study found that arterial constriction was always accompanied by increased mitochondrial fission in smooth muscle cells, whereas inhibition of mitochondrial fission in smooth muscle cells was associated with arterial relaxation. Here, we used the typical vasorelaxants, verapamil and phentolamine, to further confirm the coupling between arterial constriction and mitochondrial fission in rat aorta. Results showed that phentolamine but not verapamil induced vasorelaxation in phenylephrine(PE)-induced rat thoracic aorta constriction. Verapamil, but not phentolamine, induced vasorelaxation in high K^+(KPSS)-induced rat thoracic aorta constriction. Pre-treatment with phentolamine prevented PEbut not KPSS-induced aorta constriction and pre-treatment with verapamil prevented both PE-and KPSSinduced aorta constriction. Transmission electron microscopy(TEM) results showed that verapamil but not phentolamine inhibited KPSS-induced excessive mitochondrial fission in aortic smooth muscle cells,and verapamil prevented both PE-and KPSS-induced excessive mitochondrial fission in aortic smoothmuscle cells. Verapamil inhibited KPSS-induced excessive mitochondrial fission in cultured vascular smooth muscle cells(A10). These results further demonstrate that arterial relaxation is coupled to inhibition of mitochondrial fission in arterial smooth muscle cells.

The effects of scorpion(Buthus martensi Karsch)venom on rat left ventricular function

In order to investigate the cardiovascular effects of the scorpion(Buthus martensiKarsch)venom(BmKv),the left ventricle of the rats was catheterized via the right carotidartery.The LVP,LVEDP,+dp/dt max,Vmax,HR and BP were observed.The results showedthat intravenous injection of the BmKv(60μg/kg),in comparison with the control,elicited obvi-ous hypertension and increase of cardiac contractility,both of which lasted for 1h,while theheart rate had no significant change rand that pretreating the rats with alpha-adrenergic blocker,phentolamine,antagonized the hypertensive effects,but did not antagonize the increase of cardiaccontractility.Pretreatment with beta-adrenergic blocker,propranolol,has no influence on the ef-fects of the venom.It is suggested that the hypertensive effects are due to the activation of al-pha-adrenergic receptor,whereas the increase of cardiac contractility may not be resulted fromthe activation of beta-adrenergic receptor.The BmKv treated with dithiothreitol before injectionhad no cardiovascular effects,indicating that the intact disulfide bridges play a decisive role inthe cardiovascular effects of the BmKv.

小剂量酚妥拉明治疗重度妊高症的护理体会

本院近3年来收治重度妊高症16例,我们采用小剂量酚妥拉明(phentolamine)静脉滴注,取得较好疗效,简介护理要点及体会如下: 1 临床资料 16例中,年龄25～37岁。初产妇12例,经产妇4例。孕周37～41周。血压18.3～21.5/14.0～19.6kPa,心率在116～168,尿蛋白++～卌,全身性水肿(体重增加7.2～2.5Kg/周)。16例临床表现均有头痛、

Vasorelaxant effect of osthole on isolated thoracic aortic rings in rats

OBJECTIVE: To investigate the effect of osthole on isolated thoracic aortic rings, and to determine the potential mechanism of action.METHODS: Thoracic aortas were isolated from Wistar rats, and were suspended in tissue organ chambers for vascular tension measurement. The effect of cumulative osthole(10-9, 10-8, 10-7, 10-6, and 10-5 mol/L) on endothelium-intact and endothelium-denuded thoracic aortic rings pre-contracted with phenylephrine(PE, 10-6 mol/L) or KCl(6 × 10-2 mol/L) was recorded. Histomorphological changes of thoracic aorta were analyzed by hematoxylin-eosin. The effects of different osthole concentrations on endothelium-intact aortic rings, which were pre-inhibited with the non-selective nitric oxide synthase inhibitor L-Arg(NO2)-OMe·HCl(3 × 10-4 mol/L), endothelium-derived nitric oxide synthase inhibitor Nω-nitro-L-arginine(3 × 10-4 mol/L), guanylate cyclase inhibitor 1 H-[1,2,4] oxadiazolo [4,3-α]quinoxaline-1-one(10-5 mol/L), cyclooxygenase inhibitor indometacin(10-5 mol/L), and the Ca2+-activated potassium channel inhibitor tetraethylammonium nitrate(10-5 mol/L), and then contracted with PE, were examined. Aortic rings incubated with osthole(10-5 mol/L), phentolamine(10-5 mol/L), or verapamil(10-5 mol/L) in Ca2+-free Krebs-Henseleit solution(KHS) were stimulated with PE or KCl.RESULTS: There was a dose-dependent increase in vasorelaxation of isolated thoracic aortic rings(both with and without endothelium) with increasing osthole concentration. Hematoxylin-eosin staining showed that osthole significantly improved thoracic aorta ring morphology. Compared with the control group, there were also significant differences after incubation with L-Arg(NO2)-OMe ω-nitro-L-arginine, and 1 H-[1,2,4] oxadiazo·lo HCl,N [4,3-α] quinoxaline-1-one(P < 0.05 for all). The relaxation rate of the rings in the osthole group incubated with indometacin and tetraethylammonium nitrate were similar to controls. In Ca2+-free KHS, the PE-induced contraction was similar between the osthole(4.37% ± 0.41%) and control(4.21% ± 1.33%)groups. However, after cumulative CaCl2(0.5, 1, 1.5,2, 2.5, and 3 mmol/L), the Ca2+-induced contraction was significantly inhibited in the osthole and phentolamine groups compared with controls(P < 0.05).After cumulative CaCl2 was added to Ca2+-free KHS(high K+ concentration), the contraction rate was significantly higher than both of the control and the osthole groups(P < 0.05). The contraction rate in the osthole group was higher than the verapamil group(P < 0.05).CONCLUSION: Osthole has a vasorelaxant effect on isolated rat thoracic aortic rings, via inhibition of both receptor-operated and voltage-dependent Ca2+channels in arterial smooth muscle, leading to decreased Ca2+ influx, and via inhibition of nitric oxide release on arterial endothelial cells.