The present study was undertaken to examine whether the beta adrenergic agonist, isoproterenol, increases plasma renin activity (PRA) by activation of intrarenal or extrarenal pathways. The effects of intravenous (i.v.) and renal arterial infusion of isoproterenol on PRA and renin secretion rate (RSR) were compared in anesthetized dogs. In 12 studies in 9 dogs i.v. infusion of isoproterenol (0....

BACKGROUND Autonomic modulation, especially increased sympathetic activity may play a role in the genesis of ventricular arrhythmias. The purpose of this study was to determine whether beta-sympathetic stimulation with isoproterenol would alter sustained ventricular tachycardia (VT) circuits similarly during the drug-free and antiarrhythmic drug-treated states. METHODS AND RESULTS Twenty-five...

The ability of the M2 muscarinic receptor to mediate an inhibition of the relaxant effects of forskolin and isoproterenol was investigated in guinea pig ileum and trachea. In some experiments, trachea was first treated with 4-diphenylacetoxy-N-methylpiperidine (4-DAMP) mustard to inactivate M3 receptors. The contractile response to oxotremorine-M was measured subsequently in the presence of bot...

This study evaluated the cardiac and pulmonary effects of administering multiple inhaled doses of albuterol, isoproterenol sulfate, and placebo in ten patients with reversible obstructive disease of the airways. The pulmonary effects of therapy with albuterol were similar in magnitude to those of isoproterenol but lasted longer. The inotropic and chronotropic effects of therapy with isoproteren...

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) o...

To determine if cardiac tissue is capable of modulating its response to a stimulating hormone, we studied desensitization to the positive inotropic effect of catecholamines on embryonic chick ventricular tissue using a phase contrast microscope-video motion detector system and correlated the contractility findings with concurrent observations of /?-adrenergic receptor properties and adenylate c...

Young and old volunteers received acetazolamide systemically or isoproterenol topically. Although the responses of the two groups of volunteers were quite similar for acetazolamide, they differed significantly for isoproterenol. It is suggested that a normal aging change is altered responsiveness of the site of aqueous production and of the outflow pathways to topical isoproterenol. The site of...

Cytoskeletal organization in organ cultured embryonic chicken lens was affected by isoproterenol treatment. Immunofluorescent localization of a 49 kD fiber cell-specific cytoskeletal protein showed a cytoplasmic and membrane localization in control lenses. Following isoproterenol treatment, fluorescence was predominantly membrane-associated. Changes in 49 kD distribution as determined by immuno...

BACKGROUND Rapid anterograde conduction in the setting of ventricular preexcitation is associated with an increased risk of sudden cardiac death. The effect of isoproterenol in this setting is unclear, particularly in younger anesthetized patients. The aim of this study was to determine the effect of isoproterenol on accessory-pathway conduction in children undergoing general anesthesia and its...

During treatment of primary cultured hepatocytes with either glucagon or isoproterenol for several hours, the stimulations of cAMP formation by these hormones decreased time dependently. Glucagon treatment also reduced the response to isoproterenol, but isoproterenol treatment did not decrease the response to glucagon. Treatment with isoproterenol caused more rapid desensitization than treatmen...