Solid plexiglass clips to induce reproducible renal hypertension in the rat

Objective: The objective of this study was to induce reproducible renal hypertension in rats using plexiglass clips, and to compare it with that induced by silver clips. Materials and Methods: Saw blades (0.21-0.22 mm thick ) were used to make clips (4 x 2 x 2 mm) from a piece of 2-mm thick plexiglass. Rats were subjected to sham-operation or placement of plexiglass or silver clips around left renal artery, and 4 weeks later their mean blood pressure (MBP, mmHg), heart rate (HR, bpm), and heart weight (HW), left kidney weight (LKW), right kidney weight (RKW) and body weight (BW, g) were determined. The RKW, LKW and HW were calculated as a percentage of body weight. Results: Four weeks after sham-operation or placement of clips around renal artery, MBP, HW and RKW were significantly higher and LKW was significantly lower in left renal artery-clipped rats using plexiglass or silver clips than sham-operated ones. There was also no significant differnce among the values of HR or BW from the 3 groups. Moreover, there was no significant difference among MBP, HR, LKW, RKW or BW from sham-operated or renal artery-clipped rats. Conclusion: The findings suggest that placement of solid plexiglass clips around left renal artery resulted in hypertension comparable to that induced by silver clips

Chronic 17β-estradiol augments relaxant role of basal nitric oxide in blood vessels from rats with heart failure

The effects of chronic 17β-estradiol on endothelium-dependent relaxation to acetylcholine (ACh) and contraction to N(G)-nitro-L-arginine methyl ester (L-NAME), and endothelium-independent relaxation to sodium nitroprusside (SNP) were examined on blood vessels from rats with chronic heart failure (CHF). Two groups of ovariectomized female (50-60 days) rats were implanted with pellets containing 17β-estradiol (25 μg/day) or vehicle, and given ligation of the left main coronary artery 1 week later. Another group of ovariectomized rats was implanted with vehicle pellets, and sham-operated. After 7 weeks, thoracic aortic rings, pulmonary artery rings, and portal vein strips were prepared for in vitro studies. Relative to sham- operated rats treated with the vehicle, vessels from vehicle-treated, coronary-ligated rats had similar relaxation to ACh and SNP but reduced response to L-NAME that was significant (P<0.05) for the aorta and portal vein but not pulmonary artery. Treatment of ligated rats with 17β-estradiol augmented responses to L-NAME in the aorta, pulmonary artery and portal vein to values above those in sham-operated rat. 17β-Estradiol did not affect relaxation of any vessels to SNP and increased maximum relaxation to ACh only in the portal vein. Hence, 17β-estradiol enhances the relaxant role of basal nitric oxide in CHF.link_to_subscribed_fulltex

The Effects of Hesperidin, on Cardiac Dysfunction of Experimental Type-I Diabetic Rats

ABSTRACT: Introduction & Objective: Flavonoids are polyphenolic compounds, which are considered as antioxidants due to their ability to scavenge free radicals and inhibit enzymes in oxygen-reduction pathways. Various studies have shown that these products reduce the cardiovascular disease mortalities. Heart failure is one the main cause of mortality in diabetic patients. It is believed that diabetes has deleterious cardiomyopathic effects, which would lead to heart failure. Several evidences indicate that oxidative stress is an important factor in the pathogenesis of diabetic complications, including cardiomyopathy. The objective of the present study was to examine the effects of hesperidin on cardiac function parameters in experimental diabetes mellitus type 1 (DM1). Material & Methods: Diabetes mellitus was induced in rats by single intraperitoneal injections of streptozotocin (60mg/kg). Diabetic rats were given oral Hesperidin (500 mg/kg) for two months. Afterwards, the animals' hearts were used to study left ventricular systolic pressure (LVSP), rate of rise (+dP/ dT) and rate of decrease (-dP/ dT) of left ventricular pressure, using Langendorff isolated heart apparatus. Results: Diabetes significantly reduced the LVSP, +dP/ dT and -dP/ dT compared to the control group(p<0.05). Hesperidin significantly improved all measured parameters in diabetic animals(p<0.05). Conclusion: These results show that hesperidin can improve diabetic cardiomyopathy in experimental diabetes mellitus

Purinergic receptors in the splanchnic circulation

There is considerable evidence that purines are vasoactive molecules involved in the regulation of blood flow. Adenosine is a well known vasodilator that also acts as a modulator of the response to other vasoactive substances. Adenosine exerts its effects by interacting with adenosine receptors. These are metabotropic G-protein coupled receptors and include four subtypes, A1, A2A, A2B and A3. Adenosine triphosphate (ATP) is a co-transmitter in vascular neuroeffector junctions and is known to activate two distinct types of P2 receptors, P2X (ionotropic) and P2Y (metabotropic). ATP can exert either vasoconstrictive or vasorelaxant effects, depending on the P2 receptor subtype involved. Splanchnic vascular beds are of particular interest, as they receive a large fraction of the cardiac output. This review focus on purinergic receptors role in the splanchnic vasomotor control. Here, we give an overview on the distribution and diversity of effects of purinergic receptors in splanchnic vessels. Pre- and post-junctional receptormediated responses are summarized. Attention is also given to the interactions between purinergic receptors and other receptors in the splanchnic circulation