Lack of Involvement of Protein Kinase A Phosphorylation in Voltage-Dependent Facilitation of the Activity of Human Cardiac L-Type Calcium Channels

1996 ◽  
Vol 221 (2) ◽  
pp. 446-453 ◽  
Author(s):  
Jörg Eisfeld ◽  
Gabor Mikala ◽  
Arnold Schwartz ◽  
Gyula Varadi ◽  
Udo Klöckner
Keyword(s):  
Protein Kinase ◽  
Calcium Channels ◽  
Protein Kinase A ◽  
Voltage Dependent ◽  
Kinase A

scholarly journals Protein kinase A reduces voltage-dependent Na+ current in Xenopus oocytes

1992 ◽  
Vol 12 (10) ◽  
pp. 3743-3752 ◽  
Author(s):  
E Gershon ◽  
L Weigl ◽  
I Lotan ◽  
W Schreibmayer ◽  
N Dascal
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Xenopus Oocytes ◽  
Na Current ◽  
Voltage Dependent ◽  
Kinase A

scholarly journals Protein kinase A modulation of CaV1.4 calcium channels

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Lingjie Sang ◽  
Ivy E. Dick ◽  
David T. Yue
Keyword(s):  
Protein Kinase ◽  
Calcium Channels ◽  
Protein Kinase A ◽  
Kinase A

Ca2+-induced Ca2+ release involved in positive inotropic effect mediated by CGRP in ventricular myocytes

1999 ◽  
Vol 276 (1) ◽  
pp. R259-R264 ◽  
Author(s):  
Ming-He Huang ◽  
Paul R. Knight ◽  
Joseph L. Izzo
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Ventricular Myocytes ◽  
Maximum Velocity ◽  
Ventricular Contractility ◽  
Adult Rat ◽  
Voltage Dependent ◽  
Intracellular Ca ◽  
Pm 10 ◽  
Kinase A

To investigate the effects and mechanisms of calcitonin gene-related peptide (CGRP) on ventricular contractility, ventricular myocytes isolated from adult rat and mouse hearts were exposed to CGRP. Myocyte contractility was assessed by a video edge motion detector, and the intracellular [Ca2+] transients were measured by a spectroflurophotometer in fura 2-loaded myocytes. CGRP exerted a potent concentration-dependent (10 pM–10 nM, EC50 = 44.1 pM) positive inotropism on rat ventricular myocytes. CGRP (1 nM) increased cell shortening during contraction by 140 ± 40% above baselines and increased maximum velocity of contraction and relaxation by 98 and 106%, respectively. CGRP failed to produce any response in the presence of the CGRP1 receptor antagonist. CGRP induced similar inotropic response in mouse ventricular myocytes. CGRP increased the amplitude of [Ca2+] transients of ventricular myocytes by 120 ± 25% above baseline and shortened the time of half-maximum myoplasmic Ca2+ clearance by 30 ± 5%. Increase in intracellular Ca2+mobilization by CGRP was dependent on Ca2+ influx through the activation of the L-type Ca2+ channel, because nifedipine blocked the CGRP-induced increase in [Ca2+] transients. Furthermore, CGRP failed to increase [Ca2+] transients after the inhibition of protein kinase A in ventricular myocytes. These data indicate that stimulation of mammalian ventricular myocardial CGRP1 receptors enhances [Ca2+] transients through the activation of protein kinase A, which in turn activates voltage-dependent L-type Ca2+channels. These events lead to Ca2+-induced intracellular Ca2+ release and enhanced myocyte contraction and facilitated relaxation.

Distinct voltage-dependent regulation of a heart-delayed IK by protein kinases A and C

1991 ◽  
Vol 261 (6) ◽  
pp. C1081-C1090 ◽  
Author(s):  
K. B. Walsh ◽  
R. S. Kass
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Protein Kinase A ◽  
Dependent Protein Kinase ◽  
Kinase C ◽  
Voltage Dependent ◽  
Dependent Protein ◽  
Kinetics Of ◽  
Kinase A ◽  
Stimulation Of

We have investigated the effects of stimulation of adenosine 3',5'-cyclic monophosphate-dependent protein kinase (protein kinase A) and Ca(2+)-diacylglycerol-dependent protein kinase (protein kinase C) on the delayed rectifier K+ current (IK) in guinea pig ventricular cells using a whole cell arrangement of the patch-clamp procedure. Stimulation of either protein kinase C or A resulted in enhanced IK activity. Augmentation of IK observed during stimulation of protein kinase A occurred in a markedly voltage-dependent manner, with the largest increases occurring at potentials near the threshold for IK activation. Enhancement of IK during stimulation of protein kinase C followed a different pattern, with minimal effects of the enzyme near IK threshold. Neither protein kinase A nor C altered the kinetics of IK activation, although both kinases slightly changed the kinetics of deactivation. Both kinases increased IK maximal conductance, but the effects of each kinase on the voltage-dependence of activation differed. Protein kinase A shifted IK activation toward more negative voltages but did not affect the slope of the activation curve. Protein kinase C, in contrast, changed the slope of the IK activation curve, with only a small effect on the half-maximal voltage of activation. These contrasting effects on the voltage dependence of IK activation are consistent with actions of the kinases at distinct sites on or near the IK channel protein.

Activation of mGluR5 modulates Ca2+currents in retinal amacrine cells from the chick

2004 ◽  
Vol 21 (6) ◽  
pp. 807-816 ◽  
Author(s):  
ROMINA SOSA ◽  
EVANNA GLEASON
Keyword(s):  
Protein Kinase ◽  
Protein Kinase A ◽  
Glutamate Receptors ◽  
Amacrine Cells ◽  
Voltage Gated ◽  
Metabotropic Glutamate ◽  
Direct Activation ◽  
Voltage Dependent ◽  
Kinase A ◽  
Stimulation Of

In the inner plexiform layer, amacrine cells receive glutamatergic input from bipolar cells. Glutamate can depolarize amacrine cells by activation of ionotropic glutamate receptors or mediate potentially more diverse changesviaactivation of G protein-coupled metabotropic glutamate receptors (mGluR5). Here, we asked whether selective activation of metabotropic glutamate receptor 5 is linked to modulation of the voltage-gated Ca2+channels expressed by cultured GABAergic amacrine cells. To address this, we performed whole-cell voltage clamp experiments, primarily in the perforated-patch configuration. We found that agonists selective for mGluR5, including (RS)-2-chloro-5-hydroxyphenylglycine (CHPG), enhanced the amplitude of the voltage-dependent Ca2+current. The voltage-dependent Ca2+current and CHPG-dependent current enhancement were blocked by nifedipine, indicating that L-type Ca2+channels, specifically, were being modulated. We have previously shown that activation of mGluR5 produces Ca2+elevations in cultured amacrine cells (Sosa et al., 2002). Loading the cells with 5 mM BAPTA inhibited the mGluR5-dependent enhancement, suggesting that the cytosolic Ca2+elevations are required for modulation of the current. Although activation of mGluR5 is typically linked to activation of protein kinase C, we found that direct activation of this kinase leads to inhibition of the Ca2+current, indicating that stimulation of this enzyme is not responsible for the mGluR5-dependent enhancement. Interestingly, direct stimulation of protein kinase A produced an enhancement of the Ca2+current similar to that observed with activation of mGluR5. Thus, activation of mGluR5 may modulate the L-type voltage-gated Ca2+current in these GABAergic amacrine cellsviaactivation of protein kinase A, possiblyviadirect activation of a Ca2+-dependent adenylate cyclase.

scholarly journals Functional Regulation of L-type Calcium Channels via Protein Kinase A-mediated Phosphorylation of the β2Subunit

1999 ◽  
Vol 274 (48) ◽  
pp. 33851-33854 ◽  
Author(s):  
Moritz Bünemann ◽  
Brian L. Gerhardstein ◽  
Tianyan Gao ◽  
M. Marlene Hosey
Keyword(s):  
Protein Kinase ◽  
Calcium Channels ◽  
Protein Kinase A ◽  
Functional Regulation ◽  
Kinase A
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