Cardiovascular Agents Affect the Tone of Pulmonary Arteries and Veins in Precision-Cut Lung Slices

Cardiovascular agents are pivotal in the therapy of heart failure. Apart from their action on ventricular contractility and systemic afterload, they affect pulmonary arteries and veins. Although these effects are crucial in heart failure with coexisting pulmonary hypertension or lung oedema, they are poorly defined, especially in pulmonary veins. Therefore, we investigated the pulmonary vascular effects of adrenoceptor agonists, vasopressin and angiotensin II in the model of precision-cut lung slices that allows simultaneous studies of pulmonary arteries and veins.Precision-cut lung slices were prepared from guinea pigs and imaged by videomicroscopy. Concentration-response curves of cardiovascular drugs were analysed in pulmonary arteries and veins.Pulmonary veins responded stronger than arteries to α(1)-agonists (contraction) and β(2)-agonists (relaxation). Notably, inhibition of β(2)-adrenoceptors unmasked the α(1)-mimetic effect of norepinephrine and epinephrine in pulmonary veins. Vasopressin and angiotensin II contracted pulmonary veins via V(1a) and AT(1) receptors, respectively, without affecting pulmonary arteries.Vasopressin and (nor)epinephrine in combination with β(2)-inhibition caused pulmonary venoconstriction. If applicable in humans, these treatments would enhance capillary hydrostatic pressures and lung oedema, suggesting their cautious use in left heart failure. Vice versa, the prevention of pulmonary venoconstriction by AT(1) receptor antagonists might contribute to their beneficial effects seen in left heart failure. Further, α(1)-mimetic agents might exacerbate pulmonary hypertension and right ventricular failure by contracting pulmonary arteries, whereas vasopressin might not

Catecholaminergic automatic activity in the rat pulmonary vein: electrophysiological differences between cardiac muscle in the left atrium and pulmonary vein.

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Effect of vitamin B6 on lipid peroxidation associated with exhaustive exercise in male trained rats

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Pharmacological isolation of the pulmonary veins in the rat.

Prix de Meilleur Presentation en Physiologie attribué à Pierre Bredeloux.National audienc

Automatic quantitative analysis of t-tubule organization in cardiac myocytes using ImageJ

International audienceThe transverse tubule system in mammalian striated muscle is highly organized and contributes to optimal and homogeneous contraction. Diverse pathologies such as heart failure and atrial fibrillation include disorganization of t-tubules and contractile dysfunction. Few tools are available for the quantification of the organization of the t-tubule system. We developed a plugin for the ImageJ/Fiji image analysis platform developed by the National Institutes of Health. This plugin (TTorg) analyzes raw confocal microscopy images. Analysis options include the whole image, specific regions of the image (cropping), and z-axis analysis of the same image. Batch analysis of a series of images with identical criteria is also one of the options. There is no need to either reorientate any specimen to the horizontal or to do a thresholding of the image to perform analysis. TTorg includes a synthetic "myocyte-like" image generator to test the plugin's efficiency in the user's own experimental conditions. This plugin was validated on synthetic images for different simulated cell characteristics and acquisition parameters. TTorg was able to detect significant differences between the organization of the t-tubule systems in experimental data of mouse ventricular myocytes isolated from wild-type and dystrophin-deficient mice. TTorg is freely distributed, and its source code is available. It provides a reliable, easy-to-use, automatic, and unbiased measurement of t-tubule organization in a wide variety of experimental conditions

Effects of the free radical generating system FeCl 3/ADP on reperfusion arrhythmias of rat hearts and electrical activity of canine Purkinje fibres

The aim was to evaluate the arrhythmogenic effect of a free radical generating system, FeCl 3/ADP, using two different approaches. Ventricular arrhythmias were studied in isolated rat hearts subjected to regional ischaemia and reperfusion without or with simultaneous treatment with nicergoline (0.4 mg·litre -1). In the second part of this study the electrophysiological effects of FeCl 3/ADP (0.1/1.0 μM) were investigated in normal Purkinje fibres and in Purkinje fibres from dog surviving infarction, by using conventional micro-electrode method. Hearts were obtained from male Sprague-Dawley rats, weight 250-300 g. Purkinje fibres were dissected from hearts of mongrel dogs of either sex (10-15 kg) with or without prior myocardial infarction. FeCl 3/ADP (0.1/1.0 μM and 1.0/1.0 μ M respectively) weakly changed the incidence of reperfusion induced arrhythmias. In nicergoline pretreated hearts, in which the incidence of reperfusion arrhythmias was reduced, FeCl 3/ADP (0.1/1.0 μM) did not change the incidence and the duration of reperfusion arrhythmias. In normal Purkinje fibres, FeCl 3/ADP(0.1/1.0μM) induced a decrease in action potential duration without any pronounced effect on V(max), diastolic potential, and activation potential. In Purkinje fibres from post infarct myocardium, FeCl 3/ADP decreased action potential duration, diastolic potential, and activation potential. Free radical generation did not antagonise the antiarrhythmic activity of α adrenergic blockade. Free radical generation induced slow and minor changes in electrophysiological activity of Purkinje fibres both from normal and ischaemic hearts. Our data suggest that free radical generation may not be the only mechanism involved in the genesis of reperfusion arrhythmias.link_to_subscribed_fulltex

Effects of exhaustive exersice and vitamin B6 deficiency on free radical oxidative process in male trained rats

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Biostratigraphy and biofacies of the Devonian deposits of the Kuh-e-Shorab section (southwest Damghan) based on conodont fauna

The studied section located in the Djam-Semnan area 55 kms south west Damghan, at the vicinity of the Amrovan rail way station, in the northern flank of Shorab unassymetric anticline. The section is 440 meters thick, including limestone, dolomitic limestone and sandstone with rich fossils contents (e.g.: trilobite, coral, brachiopod, crinoid segments and vertebrate remains). The lower boundary is covered with the recent alluvial and the upper boundary disconformably overlain by the red marls and sandstones of the Permian Dorud formation. In order to determine biostratigraphy and bifacies of the deposits of Bahram formation in Shorab section, twenty five samples (4-6 kgs) were collected and processed with conventional actic/formic acid. Nineteen samples were prolific and totally yielded 340 conodont elements. The extracted conodont elements mainly separated out of the carbonate units. Thirty-one species belong to four genera (Polygnathus, Icriodus, Pelecysgnathus and Ancyrodella) were discriminated as: Icriodus excavatus, I. expansus, I. cedarensis, I. subterminus, I. iowaensis, I. alternatus, I. tafilaltensis, I. brevis, I. cf. expansus, I. sp., Polygnathus brevilaminus, Poly. angustidiscus, Poly. pollocki, Poly. cf. webbi, Poly. aspelundi, Poly. politus, Poly. alatus, Poly. webbi, Poly. cf. olgae, Poly. dubius, Poly. xylus, Poly. zinaidae, Poly. sp., Pelekeygnathus inclinathus, Pele. serradentatus, Pele. sp., Ancyrodella pristina, Acny. cf. pristina, Ancy. aff. binodosa, Ancy. sp. Based on the frequency and distribution of the collected elements Late Givetian to Early Famennian age were suggested to the studied interval. Conodonts biofacies (icriodid-polygnathid) confirm the deposition of the Bahram formation of the Shorab section in the shallow carbonate condition

Influence of dietary polyinsatured fatty acids on contractility,lusitropy and compliance of isolated rat myocardium

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