?1-adrenergic stimulation mediates Ca2+-dependent inositol phosphate formation through the ?1B-like adrenoceptor subtype in adult rat cardiac myocytes

2001 ◽  
Vol 84 (1) ◽  
pp. 201-210
Author(s):  
Stelios Seraskeris ◽  
Antigone Lazou
1998 ◽  
Vol 507 (2) ◽  
pp. 527-539 ◽  
Author(s):  
Maxim Dobretsov ◽  
Stephanie L. Hastings ◽  
Joseph R. Stimers

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

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