It has been customary to regard the heart as a pump maintaining the flow of blood, and to assess the work done by the heart from the pressure and volume of blood leaving the ventricles. While correct in physical terms, measurement of external cardiac work in this way is a poor index of the myocardial oxygen consumption which is related to the work done by the ventricular muscle. Systolic pressu...

In Schistosoma mansoni-infected mice, gastrointestinal transit was measured in vivo and the neuromuscular function of longitudinal muscle strips of inflamed ileum and noninflamed gastric fundus was assessed in vitro. Eight weeks after infection, the ileal wall was acutely inflamed, as shown by a mucosal inflammatory infiltrate, leading to an increase in mucosal thickness, in myeloperoxidase (MP...

Objective: To assess the relation between myocardial viability, coronary flow reserve, and recovery of myocardial contractility after stenting for acute myocardial infarction. Design: Consecutive sample prospective study. Setting: University hospital. Patients: 41 patients with single vessel disease and successful primary stenting for a first acute myocardial infarction. Interventions: Tl singl...

OBJECTIVE To investigate the inhibitory effect of tadalafil on the contractility of isolated nonpregnant human myometrium. MATERIALS AND METHODS The ability of tadalafil (25, 40, and 63 μM) to inhibit 55 mM KCl-induced contractility of isolated nonpregnant human myometrium was studied. The ability of the ATP-sensitive potassium channel blocker glibenclamide (10 μM) and the calcium-sensitive p...

In heart failure, reduced cardiac contractility is accompanied by blunted cAMP responses to beta-adrenergic stimulation. Parathyroid hormone (PTH)-related peptide and arginine vasopressin are released from the myocardium in response to increased wall stress but do not stimulate contractility or adenylyl cyclase at physiological concentrations. To bypass the defective beta-adrenergic signaling c...

The way that contractility varies between beats—the force-frequency relationshipwas determined for rabbit papillary muscles held at different lengths. When the maximum rate of rise of tension in a contraction, Fmai, was used as a measure of contractility, the way contractility changed between contractions was independent of length. That is, when the values of Fmax obtained at one length were mu...

Amrinone, a bipyridine compound, has been shown to exert a positive inotropic effect on the heart, without producing cardiac arrhythmias. Because of preliminary observations suggesting that the actions of amrinone might change significantly with growth and development, we studied its effects on the contractility and electrophysiology of isolated cardiac muscle of 0to 96-day-old beagles and Purk...

Systolic heart failure (HF) is a systemic disease caused by reduced cardiac contractility. Although it would seem logical that this disease could be treated with strategies to directly improve contractility, inotropic therapies in the HF population have universally failed to live up to their expectations. Paradoxically, favorable outcomes can be achieved by administering drugs that may transien...

Background & Aims: Considering increasing incidence of cardiovascular disorders in diabetes mellitus and some evidence on antioxidant and antidiabetic potentials of naringenin, this study was conducted to evaluate the beneficial effects of 6-week administration of naringenin on contractile reactivity of isolated thoracic aorta in diabetic rats. Methods: Male Wistar rats were divided into contro...

The PTEN/PI3K signaling pathway regulates a vast array of fundamental cellular responses. We show that cardiomyocyte-specific inactivation of tumor suppressor PTEN results in hypertrophy, and unexpectedly, a dramatic decrease in cardiac contractility. Analysis of double-mutant mice revealed that the cardiac hypertrophy and the contractility defects could be genetically uncoupled. PI3Kalpha medi...