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| Olivoto,R.R.; Damiani,C.E.N.; Kassouf Silva,I.; Lofrano-Alves,M.S.; Oliveira,M.A.; Fogaça,R.T.H.. |
| In cardiac and skeletal muscle, eugenol (μM range) blocks excitation-contraction coupling. In skeletal muscle, however, larger doses of eugenol (mM range) induce calcium release from the sarcoplasmic reticulum. The effects of eugenol are therefore dependent on its concentration. In this study, we evaluated the effects of eugenol on the contractility of isolated, quiescent atrial trabeculae from male Wistar rats (250-300 g; n=131) and measured atrial ATP content. Eugenol (1, 3, 5, 7, and 10 mM) increased resting tension in a dose-dependent manner. Ryanodine [100 µM; a specific ryanodine receptor (RyR) blocker] and procaine (30 mM; a nonspecific RyR blocker) did not block the increased resting tension induced by eugenol regardless of whether extracellular... |
| Tipo: Info:eu-repo/semantics/article |
Palavras-chave: Eugenol; Atrial trabeculae; Resting tension; Ryanodine; Rat; ATP. |
| Ano: 2014 |
URL: http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2014000400328 |
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| MACKENZIE,LAUREN; RODERICK,H. LLEWELYN; PROVEN,ANDREW; CONWAY,STUART J; BOOTMAN,MARTIN D. |
| Inositol 1,4,5-trisphosphate (InsP3) is an established calcium-mobilizing messenger, which is well-known to activate Ca2+ signaling in many cell types. Contractile cardiomyocytes express hormone receptors that are coupled to the production of InsP3. Such cardioactive hormones, including endothelin, may have profound inotropic and arrhythmogenic actions, but it is unclear whether InsP3 underlies any of these effects. We have examined the expression and localization of InsP3 receptors (InsP3Rs), and the potential role of InsP3 in modulating cardiac excitation-contraction coupling (EC coupling). Stimulation of electrically-paced atrial and ventricular myocytes with a membrane-permeant InsP3 ester was found to evoke an increase in the amplitudes of action... |
| Tipo: Journal article |
Palavras-chave: Calcium; Cardiac; Inositol; Arrhythmia; Ryanodine. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000400008 |
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| WILLIAMS,ALAN J; TANNA,BHAVNA. |
| Ryanodine binds with high affinity and specificity to a class of Ca2+-release channels known as ryanodine receptors (RyR). The interaction with RyR results in a dramatic alteration in function with open probability (Po) increasing markedly and rates of ion translocation modified. We have investigated the features of ryanodine that govern the interaction of the ligand with RyR and the mechanisms underlying the subsequent alterations in function by monitoring the effects of congeners and derivatives of ryanodine (ryanoids) on individual RyR2 channels. While the interaction of all tested ryanoids results in an increased Po, the amplitude of the modified conductance state depends upon the structure of the ryanoid. We propose that different rates of cation... |
| Tipo: Journal article |
Palavras-chave: Calcium; Ca2+-release channel; Sarcoplasmic reticulum; Ryanodine; Single channel. |
| Ano: 2004 |
URL: http://www.scielo.cl/scielo.php?script=sci_arttext&pid=S0716-97602004000400006 |
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