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BACKGROUND In cardiac hypertrophy, ECG T-wave changes imply an abnormal sequence of ventricular repolarization. We investigated the hypothesis that this is due to changes in the normal regional differences in action potential duration. We assessed the contribution of potassium- and calcium-dependent currents to these differences. Both the altered sequence(More)
Cardiac hypertrophy was induced in rats by daily injection of isoproterenol (5 mg/kg ip) for 7 days. Membrane voltage and currents were recorded using the whole cell patch-clamp technique in left ventricular myocytes from control and hypertrophied hearts. Ryanodine-sensitive delayed afterdepolarizations (DADs) and transient inward current (I(ti)) appeared(More)
OBJECTIVE To investigate electrical and mechanical properties of single myocytes isolated from different regions of the left ventricle in control and hypertrophied hearts. METHODS Mild cardiac hypertrophy was induced in guinea-pigs by aortic constriction. Myocytes were isolated from basal sub-endocardial, basal mid-myocardial and apical sub-epicardial(More)
OBJECTIVE To compare the properties of single myocytes isolated from different layers of the basal region of the left ventricle and to test the hypothesis that differences in the delayed rectifier current (IK) contribute to regional differences in action potential duration. METHODS Myocytes were isolated from basal sub-endocardial, mid-myocardial and(More)
Major regional differences in the electrical properties of myocytes from ventricular muscle have been described previously, on the basis of samples taken from a maximum of three regions in each heart. In order to define the topographical basis for such differences, we studied the electrical and mechanical properties of single myocytes isolated from 20(More)
Horse flies feed from superficial haematomas and probably rely heavily on the pharmacological properties of their saliva to find blood. Here we describe the first evidence of vasodilators in horse fly Hybomitra bimaculata (Diptera, Tabanidae) salivary gland extract and clone and express one of the active peptides (termed vasotab). Physiological tests using(More)
We have investigated the effects of midazolam on circulating concentrations of pituitary and pancreatic hormones in eight healthy patients during cholecystectomy and compared the changes with those in a control group of eight patients. Anaesthesia was induced either with midazolam 0.42 mg kg-1 i.v. followed by an infusion of midazolam 0.125 mg kg-1 for 1 h,(More)
We have demonstrated that the novel hypothalamic peptide pituitary adenylate cyclase-activating polypeptide (PACAP-38; 0.1-100 nmol/l) caused an increase in the release of GH, ACTH, LH and alpha-subunit and accumulation of intracellular cyclic AMP from dispersed rat anterior pituitary cells in static culture for 24 h. There were no significant effects on(More)
OBJECTIVE Catecholamines that accompany acute physiological stress are also involved in mediating the development of hypertrophy and failure. However, the cellular mechanisms involved in catecholamine-induced cardiac hypertrophy, particularly Ca2+ handling, are largely unknown. We therefore investigated the effects of cardiac hypertrophy, produced by(More)
To determine the site of action of fentanyl in attenuating the pituitary-adrenal response to surgery, we have measured serum concentrations of cortisol and growth hormone during and after a standardized surgical procedure in two groups of patients. One group received fentanyl 15 micrograms kg-1 i.v. immediately before the start of surgery; a second group(More)