Basic FGF Enhances Calcium Permeable Channel Openings in Adult Rat Cardiac Myocytes: Implication in the bFGF-induced Increase of Free Ca2+Content

1997 ◽  
Vol 29 (10) ◽  
pp. 2687-2698 ◽  
Author(s):  
Pierre-Laurent Merle ◽  
Yves Usson ◽  
Michel Robert-Nicoud ◽  
Jean Verdetti
PLoS ONE ◽  
2012 ◽  
Vol 7 (6) ◽  
pp. e39009 ◽  
Author(s):  
Hirotaka Ata ◽  
Deepa Shrestha ◽  
Masahiko Oka ◽  
Rikuo Ochi ◽  
Chian Ju Jong ◽  
...  

1994 ◽  
Vol 266 (1) ◽  
pp. C37-C41 ◽  
Author(s):  
T. A. Kinard ◽  
X. Y. Liu ◽  
S. Liu ◽  
J. R. Stimers

To determine if environmental factors influence the external K (K0) dependence of Na-K pump current (Ip), we systematically varied internal (pipette) Na (Napip) and Na-K pump activity while measuring the K0 dependence in adult rat cardiac myocytes. For each Napip, reactivation of Ip by K0 was dose dependent. The maximal Ip (Ipmax) and apparent affinity for K0 binding to the Na-K pump (K0.5) increased as Napip increased. The results of making an equimolar substitution of tetramethylammonium for K and Cs, and partial Ip inhibition with ouabain, also showed that Ipmax and K0.5 increased as Napip increased. We simulated pump activity as a function of intracellular Na (Nai) and K0 using a cyclic model of the Na-K pump and found that the model predicts K0.5 for K0 binding increases as Na increases, even when the conditions are adjusted by removing pipette K and partial pump inhibition with ouabain.


2005 ◽  
Vol 33 (05) ◽  
pp. 797-806 ◽  
Author(s):  
Jin Tao ◽  
Hongyi Wang ◽  
Jiandong Chen ◽  
Huae Xu ◽  
Shengnan Li

The saponin monomer 13 of dwarf lilyturf tuber (DT-13), one of the saponin monomers of dwarf lilyturf tuber, has been found to have potent cardioprotective effects. In order to investigate the effect of DT-13 on L-type calcium currents ( I Ca,L ), exploring the mechanisms of DT-13's cardioprotective effects, we directly measured the I Ca,L in the adult rat cardiac myocytes exposed to DT-13 using standard whole-cell patch-clamp recording technique. Our results showed that DT-13 exerted inhibitory effects on the I Ca,L of the single adult rat cardiac myocytes. The current density was reduced by about 38% after exposure of the cells to DT-13 (0.1 μM) for 10 minutes, from the control value of 7.46 ± 1.31 pA/pF to 4.25 ± 0.35 pA/pF ( n = 6, p < 0.05). This I Ca,L -inhibiting action of DT-13 was concentration-dependent. DT-13 up-shifted the current-voltage (I-V) curve, but did not significantly affect the half activation potential (V0.5). V0.5 was from -11.8 ± 0.9 mV in the control to -12.6 ± 1.9 mV in the presence of DT-13 at 0.1 μmol/L. DT-13 at 0.1 μM did not markedly affect the activation of I Ca,L , but shifted the inactivation curve of I Ca,L to the left. In combination with previous reports, these results suggest that there might be a close relationship between the cardioprotective effects of dwarf lilyturf tuber and the inhibitory effects of DT-13 on L-type calcium currents.


FEBS Letters ◽  
1983 ◽  
Vol 163 (2) ◽  
pp. 292-296 ◽  
Author(s):  
Frederick P. Walters ◽  
Frances G. Kennedy ◽  
Dean P. Jones

2002 ◽  
Vol 365 (3) ◽  
pp. 757-763 ◽  
Author(s):  
Thomais MARKOU ◽  
Antigone LAZOU

G-protein-coupled receptor agonists are powerful stimulators of mitogen-activated protein kinase (MAPK) cascades in cardiac myocytes. However, little is known regarding the physiological activation of enzymes downstream of MAPKs. We examined the activation of mitogen- and stress-activated protein kinase-1 (MSK1), a downstream target of MAPKs, in adult rat cardiac myocytes by phenylephrine and endothelin-1. Both agonists induced the phosphorylation of MSK1 at Thr-581 and Ser-376 but not at Ser-360. Maximal phosphorylation was observed at 10–15min after stimulation and it correlated with increased activity. Maximal activation of MSK1 in adult cardiomyocytes temporally coincided with maximal p38 MAPK activation while activation of the extracellular-signal-regulated kinase (ERK) cascade was more rapid. Phosphorylation and activation of MSK1 was completely inhibited by either PD98059 (ERK1/2 pathway inhibitor) or SB203580 (p38 MAPK inhibitor) alone. These data demonstrate that MSK1 activation in adult rat cardiac myocytes by G-protein-coupled receptor agonists requires the simultaneous activation of both the ERK and p38 MAPK pathways. However, the lack of phosphorylation at Ser-360, an identified phosphorylation site targeted by MAPKs, may indicate that MSK1 is not a direct substrate of ERK1/2 and p38 MAPK in adult rat cardiomyocytes.


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