Effects of heme oxygenase-1 upregulation on isoproterenol-induced myocardial infarction

The present study was designed to examine the effect of heme oxygenase-1 (HO-1) induction by cobalt protoporphyrin (CoPP) on the cardiac functions and morphology, electrocardiogram (ECG) changes, myocardial antioxidants (superoxide dismutase [SOD] and glutathione [GSH]), and expression of heat shock protein (Hsp) 70 and connexin 43 (Cx-43) in myocardial muscles in isoproterenol (ISO) induced myocardial infarction (MI). Thirty two adult male Sprague Dawely rats were divided into 4 groups (each 8 rats): normal control (NC) group, ISO group: received ISO at dose of 150 mg/kg body weight intraperitoneally (i.p.) for 2 successive days; ISO + Trizma group: received (ISO) and Trizma (solvent of CoPP) at dose of 5 mg/kg i.p. injection 2 days before injection of ISO, with ISO at day 0 and at day 2 after ISO injections; and ISO + CoPP group: received ISO and CoPP at a dose of 5 mg/kg dissolved in Trizma i.p. injection as Trizma. We found that, administration of ISO caused significant increase in heart rate, corrected QT interval, ST segment, cardiac enzymes (lactate dehydrogenase, creatine kinase-muscle/brain), cardiac HO-1, Hsp70 with significant attenuation in myocardial GSH, SOD, and Cx-43. On the other hand, administration of CoPP caused significant improvement in ECG parameters, cardiac enzymes, cardiac morphology; antioxidants induced by ISO with significant increase in HO-1, Cx-43, and Hsp70 expression in myocardium. In conclusions, we concluded that induction of HO-1 by CoPP ameliorates ISO-induced myocardial injury, which might be due to up-regulation of Hsp70 and gap junction protein (Cx-43).

Multual effect of glucose and calcium on their rates of intestinal absorption in anesthetized rats

In the present experiments the possible interaction between intestinal calcium and glucose absorption was tested in vivo. 54 rats [200-220 gm, each] were used and anaesthetised by thiopental Na 60 mg/kg I.P., abdomen was opened and 2 canulae were inserted at the proximal and distal ends of the small intestine. After preliminary wash with warm N. saline, different solutions containing CaCI[2] isotonic [1.1 gm%] or hypertonic [2.2 gm%], with and without N. saline + glucose 596, were administered into the intestine through the proximal canula and retained for 15 minutes and then pushed out by air. Volume and glucose or calcium content of the administered and collected perfusates were estimated. Calcium absorption was enhanced significantly [P<0.01] in the presence of glucose. Alternatively, hypertonic calcium produced significant inhibition of glucose absorption [P< 0.05]. This inhibitory effect of calcium was almost abolished by the addition of the Ca[++]channel blocker 'verapamil' in 4 mg/kg. Verapamil also decreased intestinal absorption of calcium significantly [P

Effect of different types of stress on blood glucose, triglycerides and cholesterol in rabbits

Fasting serum levels of glucose, triglycerides and cholesterol were determined and compared in 18 rabbits pre and 5 minutes post exposure to stress. Animals were fed the same type of diet for 2 weeks and then divided into 3 groups. Each group was subjected for 5 minutes to one of the following stressful conditions: a] Physical stress where rabbits were forced to run on a motorized treadmill [Healthstyler FJE-620] at a rate of 2 km/hr; b] Cold stress in which rabbits were immersed in cold water at 4 degree C, and c] Pain stress by pressing strong clamps on the fore-limbs of rabbits. Serum glucose level was increased significantly in response to all 3 stressful stimuli, while scrum triglycerides level was only increased significantly post physical and cold stresses but not after pain stress. The highest values were recorded post cold stress especially for triglycerides which reached almost triple their pre stress values. Pain stress, however, gave the smallest response. On the other hand, serum cholesterol level obtained post all 3 types of stressors was not significantly different from its pre stress value. Longer periods of stress are probably required in order to get significant changes in serum cholesterol level. Several neuro-endocrinal and chemical factors have been incriminated in this response which include: catecholamines, glucocorticoids, glucagon, plasma lipid peroxide, beta-endorphin, and endogenous opioids