The inotropic actions of isoproterenol in cat papillary muscles or trabeculae bathed in a salt solution containing 4 mM KCl were compared to those in similar muscles bathed in a salt solution containing 22 mM KC1. Although isoproterenol evoked the same increase in force of contraction in both groups of muscles, the time course of contraction differed markedly. In muscles bathed in 4 mM KC1, iso...

Cardioprotective effect of ethanolic extract of Terminalia chebula fruits (500 mg/kg body wt) was examined in isoproterenol (200 mg/kg body wt) induced myocardial damage in rats. In isoproterenol administered rats, the level of lipid peroxides increased significantly in the serum and heart. A significant decrease was observed in the activity of the myocardial marker enzymes with a concomitant i...

Experiments were performed in vitro to explore the influence of isoproterenol on the canine pelvi-ureteral system. The rhythmic changes of intrapelvic pressure became no longer manifest and simultaneously recorded electromyograms revealed disappearance of peristalsis at sites distal to the upper region of renal pelvis following application of isoproterenol, while the pacemaker at the pelvi-caly...

AimsUpregulation of Ca2+/calmodulin-dependent protein kinase II (CaMKII) contributes to the pathogenesis cardiovascular disease, including hypertension. Transgenic rats expressing human angiotensinogen gene [TGR (hAGT)L1623] are a new novel humanized model hypertension that associates with declines in cardiac contractile function and β-adrenergic receptor (AR) reserve. The molecular mechanisms ...

Background: There are controversial reports about the exact mechanisms of lead-induced hypertension, but many factors such as alteration in the responsiveness of cardiovascular system to endogenous substances including catecholamines could be one of the mechanisms involved. In present study, the effect of exposure to 100 ppm lead acetate by drinking water (in the periods of 4, 8 and 12 weeks)...

Background: Connexon is a membrane structural protein in the gap junctions. These cellular connections are responsible for transporting ions and messenger molecules to the oocyte. This study aimed to investigate the role of beta-2-adrenoceptors in the process of follicle growth based on the expression of the two connexins 37/43 in the gap junctions that have a primary role in the mitotic resump...

To determine the effect of isoproterenol on cardiac energetics and function in an animal preparation of cardiomyopathy, we studied Langendorif perfused hearts from Syrian cardiomyopathic hamsters. High-energy phosphate metabolites (phosphocreatine [PCr], ATP, inorganic phosphate [Pi]) and intracellular pH (pHi) were measured by 31P nuclear magnetic resonance spectroscopy and correlated with lef...

(over 1 •~ 10-4M). These results suggest that methoxamine possesses a direct negative inotropic action which is mainly due to a decrease in the intensity of the active state. An increase in F produced by isoproterenol was antagonized by methoxamine at a concentration about 100 times higher than that of isoproterenol, suggesting a weak beta-adrenergic blocking action of methoxamine. This antagon...

In the present work, we carry out a morphometric analysis, at ultrastructural level, of the secretory granules of the granular undulated duct of the submaxillary gland of the rat, under basal conditions (Control Group or I), following stimulation for 10 minutes with 2 mg/100 g weight of Isoproterenol (Group II), and following stimulation with 2 gammas/100 g weight of Noradrenalin for the same t...