background: selective phosphodiesterase (pde3) inhibitors improve cardiac contractility and may use in congestive heart failure. however, their proarrhythmic potential is the most important side effect. methods: in this research, we evaluated the potential cardiotonic activity of six new synthesized selective pde3 inhibitors (6-hydroxy-4-methylquinolin-2(1h)-one derivatives) using the spontaneo...

1 Cardiovascular and metabolic responses to intravenous infusion of isoprenaline were measured in fasted, anaesthetized cats. 2 Isoprenaline (0.2 mug kg-1 min-1 for 15 min) decreased diastolic blood pressure and increased heart rate, blood glucose, blood lactate and plasma free fatty acids. 3 Oxprenolol (0.5 mg/kg) antagonized all cardiovascular and metabolic effects of isoprenaline non-selecti...

we investigated the vasodilatory effect of isoprenaline at large vessels (aorta, renal ans saphenous arteries, vena cava, renal and saphenous veins) in doxorbicin-induced model of heart failure. thirty saline-treated (normal group) and thirty doxorubicin treated rabbits (1 mg/kg administered intravenously twice weekly for 8 weeks) were studied after 16 weeks of treatment. chronic heart failure ...

The intravenous infusion of isoprenaline in normal subjects causes no significant electrocardiographic abnormalities. This is in sharp contrast to the remarkably ischaemnic ST-T changes seen after infusing isoprenaline in patients with coronary artery disease. Limited experience thus far has been attended by no untoward reactions. In view of the simplicity and great sensitivity, we conclude tha...

The action of isoprenaline, a purely beta-agonist, was investigated on frog atrial fibres under voltage clamp conditions; tonic tension was induced by long depolarizing pulses and the outward delayed current simultaneously developed. The cumulative dose-response curves showed that isoprenaline increased the peak of tonic tension in the concentration range 10(-8) to 3. 10(-6) mol.l-1, with a max...

Eighteen male rabbits were used in this trial, divided into three groups of 6 each. Group A served as controls. Group B were on a placebo and received isoprenaline injections. Group C were treated with Abana and also received isoprenaline. Histamine was measured in all the three groups. A significant increase in histamine levels was observed in the isoprenaline group. Two weeks of Abana therapy...

This study was conducted to determine whether the relaxant effect of adenosine triphosphate (ATP)-sensitive potassium channel (KATP) openers on airway smooth muscle are reduced during the hyporesponsiveness of beta-adrenergic receptors. Isometric tension was measured and dose-response curves were constructed for levcromakalim (a KATP opener), Y-26763 (another KATP opener), isoprenaline and theo...

Introduction: It was shown in a previous study, that MCPIP, a cilostamide derivative, increased atrial contraction force without changing contraction rate. To improve this property, two new derivatives of cilostamide were synthesized and their effects on PDE3 activity and isolated rat atria contraction were investigated. Methods: The inhibitory effect of each compound on PDE3 enzyme was dete...

The effects of isoprenaline on the induction of supraventricular tachycardia by programmed stimulation were studied in 67 patients to see whether they correlated with spontaneous catecholamine mediated symptoms during exercise testing and Holter monitoring. Thirty seven control patients (group 1) did not have spontaneous arrhythmias either during exercise testing or Holter monitoring. Thirty pa...

In several water-breathing fish species, beta-adrenergic receptor stimulation by noradrenaline leads to a decrease in plasma free fatty acid (FFA) levels, as opposed to an increase in air-breathing mammals. We hypothesised that this change in adrenergic control is related to the mode of breathing. Therefore, cannulated air-breathing African catfish were infused for 90 min with noradrenaline or ...