Effects of nanomolar concentration dihydroouabain on calcium current and intracellular calcium in guinea pig ventricular myocytes

A mathematical model of action potentials of mouse sinoatrial node cells with molecular bases

“…Experimentally, however, we have observed that low (100 nM) or high (30 μM) concentrations of TTX used to block I Na,1.1 or I Na,1.5 , respectively, caused a reduction of d V /d t max . This may be due to TTX affecting other depolarizing Ca 2+ currents in SAN cells, as has been seen in experimental studies (75, 87). …”

Different Na+K+-ATPase signal pathways was involved in the increase of [Ca2+]i induced by strophanthidin in normal and failing isolated guinea pig ventricular myocytes

“…[Ca 2+ ] i increase and cardiac contractility was enhanced, thus the Na + /K + -ATPase inhibition theory may not properly explain the inotropic action of glycosides [2] . Although we observed that dihydroouabain (a CS) could increase [Ca 2+ ] i in non-beating myocytes via stimulating the I Ca-L and I Ca , or directly triggering a release of [Ca 2+ ] i using whole-cell patch-clamp and the confocal microscopy techniques [3] , these experiments did not detect [Ca 2+ ] i and contractility simultaneously, which still can not effectively explain the mechanisms of the inotropic actions of CS.…”

“…Evidence suggests that there is an endogenous ouabainlike factor in the heart tissue, which possesses hormonelike properties and can relay messages through various signal transduction pathways [5,13,14] . Yin et al [3] proved that low concentrations of dihydroouabain increased [ [5] . They found that the increase of contractility in cardiac myocytes does not only rely on [Ca 2+ ] i , but also on ROS generation.…”

“…Evidence suggests that there is an endogenous ouabainlike factor in the heart tissue, which possesses hormonelike properties and can relay messages through various signal transduction pathways [5,13,14] . Yin et al [3] proved that low concentrations of dihydroouabain increased [Ca 2+ ] i by Ca 2+ influx via L-type Ca 2+ channels, TTX-sensitive Na + channels, or/and by directly triggering intracellular calcium release in guinea pig cardiac myocytes, suggesting that the effects of CS might involve more complex mechanisms.…”