We studied the development of selective adrenergic and cholinergic neuroeffector transmission in primary cultures of isolated ventricular muscle cells. Explants of either thoracolumbar sympathetic ganglia or sacrococcygeal spinal cord were added to newborn rat ventricular cultures harvested prior to the onset of in vivo autonomic innervation. Neuronal growth, migration, and the formation of neu...

AIMS An attenuated heart rate response to exercise, termed chronotropic incompetence (CI), has been reported to be an independent predictor of cardiovascular mortality. We examined the change in autonomic function during exercise testing and correlated the results with CI. METHODS AND RESULTS Exercise testing using a bicycle ergometer was performed in 172 patients who had no evidence of cardi...

We systematically modified isoproterenol's chemical structure to reduce chronotropic, arrhythmogenic, and vascular side effects. Experiments on dogs showed that the resulting drug, dobutamine, had an inotropic efficacy as great as that of epinephrine due to a direct action on beta1 cardiac receptors. However, unlike epinephrine, dobutamine's effect on alpha and beta2 vascular receptors was slig...

We investigated blocking effects of the selective 8 1-adrenoceptor blocker atenolol (0.1 100 ,ug/kg, i.v.), the selective fl2-adrenoceptor blocker ICI 118,551 (1-1000 ,ug/kg, i.v.) and the com bination of the two drugs on positive chronotropic and dromotropic responses to norepinephrine (NE) released by stimulation of the sympathetic nerves in anesthetized, neurally decentralized, open-chest do...

The isolated right atrium of the dog was perfused with arterial blood introduced from a carotid artery of a support dog. The selective injection of dopamine, tyramine and norepinephrine into the cannulated sinus node artery induced dose-relatedly positive chronotropic and inotropic effects. However, for an equal increase in sinus rate, dopamine caused less increase in tension development than n...

Three presumptive cardiac tissues from aborted human embryos which ranged in length from 2 mm to 4 mm and in age from 53 days to 71 days were maintained in culture beating rhythmically for 18-88 days. Medium renewal, temperature increases (from 31° to 38°C), and pH increases (from 6.92 to 7.75) raised the pulsation rate. Excess potassium stopped the pulsation. Sympathomimetic drugs increased th...

cirrhosis is characterized by marked abnormalities in the cardiovascular system. a hyperdynamic splanchnic and systemic circulation is typical of cirrhotic patients and has been observed in all experimental forms of portal hypertension. the hyperdynamic circulation is most likely initiated by arterial vasodilatation, leading to central hypovolemia, sodium retention, and an increased intravascul...

The aim of this study was to determine whether dobutamine, dopamine, or milrinone (a phosphodiesterase [PDE] III inhibitor) would support cardiac function that had been attenuated by administration of the beta-blocker, carvedilol (0.2, 0.4, or 0.8 mg/kg). Hemodynamic and cardiac parameters including the heart rate (HR), left-ventricular fractional shortening (FS), and arterial pressure were mea...

Aims A hallmark of heart failure with preserved ejection fraction (HFpEF) is impaired exercise capacity varying severity. The main determinant cardiac output (CO), however little information available about the relation between constituents CO – rate and stroke volume in HFpEF. We sought to determine if a heterogeneity response exists patients HFpEF describe possible clinical phenotypes associa...