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Papillary muscle

Cromakalim. Cromakalim has along half-life (254). Cromakalim at an oral dose of 1.5 mg ia humans significantly lowers blood pressure 19/12 mm Hg (systohc/diastoHc pressure). It iacreases reaal blood flow, PRA, and heart rate. Cromakalim has bronchodilating activity that is beneficial for hypertensive asthmatic patients. Because of some undesirable effects seen ia cardiac papillary muscles of animals oa long-term treatmeat, future clinical trials are to be carried out usiag the active enantiomer, lemakalim (BRL 38227). [Pg.143]

Pyridyl-4-bromo-6-oxo-5,6,7,8-tetrahydrothiazolo[5,4-g]quinolones and analogues were prepared and tested as potential inotropic agents for treatment of heart failure. For example, the 2-(4-pyridyl) substituted thiazoloquinolone 38 gave a 122% increase in contractility of guinea pig papillary muscle (89EUP1). [Pg.213]

FIGURE 2.19 Potentiation and modulation of response through control of cellular processes, (a) Potentiation of inotropic response to isoproterenol in guinea pig papillary muscle by the phosphodiesterase inhibitor isobutylmethylxanthine (IBMX). Ordinates percent of maximal response to isoproterenol. Abscissa percent receptor occupancy by isoproterenol (log scale). Responses shown in absence (open circles) and presence (filled circles) of IBMX. Data redrawn from [7], (b) Effect of reduction in calcium ion concentration on carbachol contraction of guinea pig ileum. Responses in the presence of 2.5 mM (filled circles) and l.5mM (open circles) calcium ion in physiological media bathing the tissue. Data redrawn from [8],... [Pg.32]

Kihara, Y., and Morgan, J. P. (1989). A comparative study of three methods for intracellular loading of the calcium indicator aequorin in ferret papillary muscles. Biochem. Biophys. Res. Commun. 162 402—407. [Pg.410]

Karagueuzian, H.S. and Katzung, B.G. (1982). Voltage-clamp studies of transient inward current and mechanical oscillations induced by ouabain in ferret papillary muscle. J. Physiol, 327, 255-271. [Pg.71]

Discuss the functions of the chordae tendinae and the papillary muscles... [Pg.163]

Isolated right ventricular papillary muscle from guinea pig. [Pg.745]

Purkinje fibers Papillary muscle Isolated cardiac myocytes... [Pg.64]

Results of in vitro studies suggest an interaction between calcium ions and cyanide in cardiovascular effects (Allen and Smith 1985 Robinson et al. 1985a). It has been demonstrated that exposure to cyanide in metabolically depleted ferret papillary muscle eventually results in elevated intracellular calcium levels, but only after a substantial contracture develops (Allen and Smith 1985). The authors proposed that intracellular calcium may precipitate cell damage and arrhythmias. The mechanism by which calcium levels are raised was not determined. Franchini and Krieger (1993) produced selective denervation of the aortic and carotid bifurcation areas, and confirmed the carotid body chemoreceptor origin of cardiovascular, respiratory and certain behavioral responses to cyanide in rats. Bradycardia and hyperventilation induced by cyanide are typical responses evoked by carotid body chemoreceptor stimulation (Franchini and Krieger 1993). [Pg.90]

Chronotropism and inotropism Isolated atrium/papillary muscle/ isolated hearts Sugiyama et al.,-86 Voss et al.87... [Pg.257]

APD (microelectrode) Purkinje fibres papillary muscle mid-myocardial (M-cell) wedge preparation Abi-Gerges et al.,-88 Gintant et al.,-89 Lu et al. 90 Antzelevitch et al91... [Pg.257]

The Pfizer group in the United Kingdom has been actively involved in the search for new Class III antiarrhythmic agents. It has patented a variety of structural types that make extensive use of the methylsulphonylamino moiety. These include indanes [173,174], pyridines [175,176], piperazines [177-179], benzazepines [180], bisarylalkylamines [181] and diazabicyclic compounds [182], From this extensive work, two compounds, UK-66914 (65) and UK-68798 (66), have entered clinical trials. Compound (65) increases the effective refractory period (ERP) of ferret papillary muscle by 25% at a concentration of 0.5 //M [183]. Whole-cell patch-clamp studies... [Pg.90]

The Class III antiarrhythmic agent under development by Eisai is a meth-ylsulphonylamino-substituted benzoyl piperidine, E-4031 (67). In guinea-pig papillary muscle E-4031 increased APD90 by 25% at a eoncentration of 10 [190] and increased ERP in ferret papillary muscle by 25% at 58 nM... [Pg.91]

The quinolinone derivative, OPC-88117 (73), is yet another compound described as possessing both Class I and Class III electrophysiological activities. Studies in guinea-pig papillary muscle showed that OPC-88117 at 30 increased APDgo by about 15% and decreased F ,ax by only 4% however, at 100 /iM APDgo was prolonged by 23 % and was decreased by 23 % [206]. Further experiments in isolated rabbit hearts demonstrated that OPC-88117 increased atrio-His bundle (A-H) and His bundle-ventricle (H-V) conduction times and refractory periods with a profile that was similar to, but more potent than that of lidocaine [207]. [Pg.93]

At 0.1 and 0.3 /iM the compound significantly prolonged APD of guinea-pig papillary muscle with little effect on F ax [208]. At a much higher concentration (100 //M), Umax was significantly inhibited. Voltage-clamp studies with single ventricular myocytes showed that TYB-3823 blocked outward potassium currents. Further studies in vascular tissue indicated that it also blocks a- and / -receptors [209]. This may also contribute to its antiarrhythmic profile. [Pg.93]

Murrayaquinone A (107) (see Scheme 2.21) was found to produce a triphasic inotropic response of guinea-pig papillary muscle. This triphasic inotropic response is not mediated through a receptor mechanism, but through a mechanism involving ATP production (473). [Pg.192]

Secondary mitral regurgitation can be a consequence of intraventricular conduction delay. Secondary mitral regurgitation is a common accompaniment of dilated cardiomyopathy of ischemic etiology. Intraventricular conduction delays can create or exacerbate mitral regurgitation by causing a lack of coordination of the papillary muscles [95]. The geometry of the mitral papillary muscles places one near... [Pg.54]

A next-level assay is usually an isolated heart/cardiac tissue preparation. The canine Purkinje fiber assay (GLP) measures several action potential parameters, like resting membrane potential, upstroke velocity, action potential duration and shape, but also if a drug acts reverse-use dependently [72]. Based on changes of the action potential shape it is possible to conclude which ion channels are modulated (e.g., L-type calcium channel block would abolish the plateau phase). The papillary muscle assay (e.g., guinea pigs) determines similar parameters [73]. [Pg.396]

Hayashi, S., Kii, Y, Tabo, M., Fukuda, H., Itoh, T., Shimosato, T., Amano, H., Saito, M., Morimoto, H., Yamada, K., Kanda, A., Ishitsuka, T., Yamazaki, T., Kiuchi, Y, Taniguchi, S., Mori, T., Shimizu, S., Tsurubuchi, Y, Yasuda, S., Kitani, S., Shimada, C., Kobayashi, K., Komeno, M., Kasai, C., Hombo, T. and Yamamoto, K. (2005) QT PRODACT A multi-site study of in vitro action potential assays on 21 compounds in isolated guinea-pig papillary muscles. Journal of Pharmacological Sciences, 99, 423-437. [Pg.411]

Fig. 12. Left ventricular cavity opacification (a) View/ of the left ventricle (LV) of a patient without contrast agent (b) the same view after a bolus injection of a microbubble contrast agent the LV, endocardial border (LV/ENDO), and papillary muscle (PAP) are now precisely visualized, allowing myocardial (heart muscle) thickening to be evaluated. When watching the heart in motion, normal functioning heart muscle thickens as it contracts abnormal functioning heart muscle moves less and does not thicken. From Ref. [106], with permission. Fig. 12. Left ventricular cavity opacification (a) View/ of the left ventricle (LV) of a patient without contrast agent (b) the same view after a bolus injection of a microbubble contrast agent the LV, endocardial border (LV/ENDO), and papillary muscle (PAP) are now precisely visualized, allowing myocardial (heart muscle) thickening to be evaluated. When watching the heart in motion, normal functioning heart muscle thickens as it contracts abnormal functioning heart muscle moves less and does not thicken. From Ref. [106], with permission.
The heart is inspected internally following a longitudinal section into the right and left ventricles. The exposed papillary muscles and atrioventricular valves are examined. [Pg.250]


See other pages where Papillary muscle is mentioned: [Pg.129]    [Pg.31]    [Pg.1091]    [Pg.23]    [Pg.272]    [Pg.273]    [Pg.166]    [Pg.14]    [Pg.613]    [Pg.113]    [Pg.78]    [Pg.81]    [Pg.81]    [Pg.82]    [Pg.83]    [Pg.84]    [Pg.90]    [Pg.92]    [Pg.94]    [Pg.94]    [Pg.95]    [Pg.50]    [Pg.55]    [Pg.88]    [Pg.397]    [Pg.336]   
See also in sourсe #XX -- [ Pg.166 ]

See also in sourсe #XX -- [ Pg.80 , Pg.82 ]




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Canine papillary muscle, action

Canine papillary muscle, action potentials

Guinea pig papillary muscle action potential

Guinea pig papillary muscle action potential assay

Papillary muscle action potential assay

Papillary muscle negative inotropic effects

Papillary muscle rupture

Studies in Isolated Guinea Pig Papillary Muscles

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