Disease relevance of Papillary Muscles

• This study suggests that heat stress enhances the ability of rabbit papillary muscle to use pyruvate, but not glucose, after reoxygenation, and that the differences seen in contractility may be secondary to induction of the 72-kD stress protein [1].
• ERP and APD of papillary muscles were also reduced during hypoxia produced by bubbling the physiological bathing solution with N2 instead of O2 [2].
• Asymmetrical septal hypertrophy dislocates the cardiac apex and papillary muscles anteriosuperiorly producing abnormal systolic anterior mitral leaflet mition [3].
• On histologic examination, myocardial necrosis involving the right ventricular free wall in the ventriculotomy animals and the posterior papillary muscle and subadjacent free wall in the coronary occlusion animals, did not differ between the mannitol treated and control groups [4].
• Influence of rate-dependent cellular uncoupling on conduction change during simulated ischemia in guinea pig papillary muscles: effect of verapamil [5].

High impact information on Papillary Muscles

• Tumor necrosis factor alpha, interleukin-6, and interleukin-2 inhibited contractility of isolated hamster papillary muscles in a concentration-dependent, reversible manner [6].
• Mechanism of myocardial contractile depression by clinical concentrations of ethanol. A study in ferret papillary muscles [7].
• We evaluated the effects of the diterpene compound forskolin in human myocardial adenylate cyclase preparations, isolated trabeculae and papillary muscles derived from failing human hearts, and acutely instrumented dogs [8].
• Ouabain effects on intracellular potassium activity and contractile force in cat papillary muscle [9].
• Baseline isoproterenol-stimulated papillary muscle contractile force was significantly lower in the cirrhotic group; with L-NAME incubation, contractile force increased significantly in cirrhotic rats but was unaffected in the controls [10].

Chemical compound and disease context of Papillary Muscles

• In addition to demonstrating a gradual but complete reversibility of the abnormalities in papillary muscle function in diabetic rats (although control of hyperglycemia was less than ideal), this study confirms that this model of a cardiomyopathy is not a result of streptozotocin-induced cardiac toxicity [11].
• Contracture due to hypoxia, to both oxygen and glucose deficiency, and to potassium chloride was induced in rat left ventricular papillary muscle preparations [12].
• The role of local accumulation and diffusion of CO2 to modify cellular loss and extracellular accumulation of K+ during the initial, reversible phase of myocardial ischemia was investigated in isolated, cylindrical papillary muscles of the rabbit [13].
• The myocardial energetic active state. I. Oxygen consumption during tetanus of cat papillary muscle [14].
• Three weeks after myocardial infarction, when left ventricular function was impaired, catecholamine responsiveness was determined by measuring the effects of isoprenaline in the conscious animal, the isolated perfused heart, the isolated right atria, and the right papillary muscles [15].

Biological context of Papillary Muscles

• We investigated whether this depression could be due to a direct effect of ethanol on the process of electromechanical coupling by simultaneously measuring the transmembrane action potential and contraction, or the cytosolic calcium transient (via aequorin photoluminescence) and contraction in isolated ferret right ventricular papillary muscle [7].
• Isoproterenol largely restored contractility in papillary muscle and stimulated PLN phosphorylation to wild-type levels in intact hearts [16].
• Membrane potential (MP) was changed uniformly in segments (length less than or equal to 1.0 mm) of papillary muscles by applying extracellular polarizing current pulses across a single sucrose gap [17].
• Isometric contraction of isolated rat left ventricular posterior papillary muscle was virtually eliminated at the end of an exposure to 15 minutes of hypoxia and remained 40+/-5% depressed an hour after the reintroduction of O2 [18].
• The contribution of electrogenic Na(+)-HCO3- cotransport to pHi regulation during changes in heart rate was explored in cat papillary muscles loaded with BCECF-AM in bicarbonate-free (HEPES) medium and in CO2/HCO3(-)-buffered medium [19].

Anatomical context of Papillary Muscles

• The effects of erythromycin on repolarization were more marked in Purkinje fibers than in papillary muscle [20].
• Similarly, the ability of cromakalim to shorten cardiac action potential duration in guinea pig papillary muscle and to increase outward whole-cell potassium currents in isolated myocytes was inhibited by glibenclamide, whereas sodium 5-hydroxydecanoate was without effect [21].
• The influence of selective removal of the endocardial endothelium (by a 1-second exposure to the detergent Triton X-100, 0.5%) on myofilament Ca2+ responsiveness and intracellular Ca2+ transients was studied in ferret papillary muscles loaded with the Ca(2+)-regulated bioluminescent indicator aequorin [22].
• The observation that TxB2 when added to a papillary muscle or myocardial subfractions, did not decrease Tpd or ATPase suggests that TxB2 plays an indirect role in altering cardiac muscle activity [23].
• To determine whether beta 1-adrenoceptor function is impaired in heart failure selectively, beta 1- and beta 2-adrenoceptor density and functional responsiveness in the right and left atria and the left papillary muscles from patients with mitral valve disease (functional class III to IV) were studied [24].

Associations of Papillary Muscles with chemical compounds

• Right ventricular papillary muscles taken from heat-stressed and control rabbit hearts were superfused with Kreb's solution containing either glucose or pyruvate and rendered hypoxic for 30 min [1].
• Cardiac contractile function was evaluated in isolated left ventricular papillary muscles in the absence and presence of the NOS inhibitor nitro-L-arginine methyl ester (L-NAME) [10].
• In contrast, papillary muscles responded normally to calcium, and adenylate cyclase responses to fluoride and histamine were normal [25].
• In isolated canine ventricular trabeculae and papillary muscles driven electrically at 0.5 Hz at 37 degrees C, the positive inotropic effects of milrinone, amrinone, MDL 17,043, MDL 19,205, OPC-8212, and forskolin were all associated with simultaneous elevations in tissue cyclic AMP levels [26].
• Reduction of the extracellular Na+ concentration of 75% of normal potentiated the inotropic response of papillary muscles to low concentrations of milrinone, suggesting possible activation of the Na+-Ca++ exchange mechanism [27].

Gene context of Papillary Muscles

• There was a large gradient of Kv4.2 expression across the ventricular wall, and Kv4.2 expression in epicardial muscle was more than eight times higher than in papillary muscle [28].
• Isolated left ventricular papillary muscles from wild-type (WT) and phospholamban knockout (KO) mice were stimulated at 2 to 6 Hz [29].
• Polyclonal antibodies raised against a peptide sequence of the human DMPK were used to analyze the subcellular distribution of the protein in rat papillary muscles [30].
• METHODS: Experiments were performed in isometrically contracting (0.2 Hz) rat papillary muscles at 30 degrees C. DF was measured either after stretch or after the addition of ET-1 or ET-3 (in doses that increase contractility to a similar magnitude as does the SFR), with or without the selective ETA receptor antagonist BQ123 (300 nmol/L) [31].
• Concomitant administration of IGF binding protein-3 blocked IGF-1-positive inotropic action in ferret papillary muscles [32].

Analytical, diagnostic and therapeutic context of Papillary Muscles

• Both glutaraldehyde-tanned xenograft pericardial chordae (GTXP) and extruded polytetrafluorethylene chordae (ePTFE) heal to papillary muscles and cusps [33].
• A possible role for endogenous prostaglandins in the toxic electrophysiological effects of the aglycone acetylstrophanthidin was studied in isolated canine Purkinje fiber papillary muscle preparations by standard microelectrode techniques [34].
• Using another tracer, one can monitor myocardial perfusion in the left and right ventricular walls, even in structures as small as the papillary muscles [35].
• Absence of xanthine oxidising activity was also observed with human papillary muscle extracts that were subjected to either ultrafiltration or gel filtration [36].
• The effect of diltiazem on the contractile and vascular responses to 2 min of total occlusion and reperfusion was investigated in isolated blood-perfused canine papillary muscle preparations [37].

References