scholarly journals Hyposmotic challenge modulates function of L-type calcium channel in rat ventricular myocytes through protein kinase C

2010 ◽  
Vol 31 (11) ◽  
pp. 1438-1446 ◽  
Author(s):  
An-tao Luo ◽  
Hong-yan Luo ◽  
Xin-wu Hu ◽  
Lin-lin Gao ◽  
Hua-min Liang ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Calcium Channel ◽  
Ventricular Myocytes ◽  
Rat Ventricular Myocytes ◽  
Kinase C

Arachidonic acid enhances contraction and intracellular Ca2+ transients in individual rat ventricular myocytes

1997 ◽  
Vol 272 (1) ◽  
pp. H350-H359 ◽  
Author(s):  
D. S. Damron ◽  
B. A. Summers
Keyword(s):  
Arachidonic Acid ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Cardiac Muscle ◽  
Ventricular Myocytes ◽  
Contractile Function ◽  
Receptor Activation ◽  
K Channels ◽  
Rat Ventricular Myocytes ◽  
Kinase C

Modulation of intracellular free Ca2+ concentration ([Ca2+]i) by inotropic stimuli alters contractility in cardiac muscle. Arachidonic acid (AA), a precursor for eicosanoid formation, is released in response to receptor activation and myocardial ischemia and has been demonstrated to alter K+ and Ca2+ channel activity. We investigated the effects of AA on contractility by simultaneously measuring [Ca2+]i and shortening in single field-stimulated rat ventricular myocytes. [Ca2+]i transients were measured using fura 2, and myocyte shortening was assessed using video edge detection. AA stimulated a doubling in the amplitude of the [Ca2+]i transient and a twofold increase in myocyte shortening. In addition, AA stimulated a 30% increase in the time to 50% diastolic [Ca2+]i and a 35% increase in the time to 50% relengthening. These effects of AA were mediated by AA itself (56 +/- 5%) and by cyclooxygenase metabolites. Pretreatment with the protein kinase C inhibitors staurosporine and chelerythrine nearly abolished (> 90% inhibition) these AA-induced effects. Inhibition of voltagegated K+ channels with 4-aminopyridine mimicked the effects of AA. Addition of AA to the 4-aminopyridine-treated myocyte had no additional effect on parameters of contractile function. These data indicate that AA alters the amplitude and duration of Ca2- transients and myocyte shortening via protein kinase C-dependent inhibition of voltage-gated K+ channels. Release of AA by phospholipases in response to receptor activation by endogenous mediators or pathological stimuli may be involved in mediating inotropic responses in cardiac muscle.

Enhancement of contraction and L-type Ca2+ current by murrayafoline-A via protein kinase C in rat ventricular myocytes

2016 ◽  
Vol 784 ◽  
pp. 33-41
Author(s):  
Bojjibabu Chidipi ◽  
Min-Jeong Son ◽  
Joon-Chul Kim ◽  
Jeong Hyun Lee ◽  
Tran Quoc Toan ◽  
...  
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Ventricular Myocytes ◽  
Rat Ventricular Myocytes ◽  
Kinase C

Isoenzyme-selective regulation of SERCA2 gene expression by protein kinase C in neonatal rat ventricular myocytes

2003 ◽  
Vol 285 (1) ◽  
pp. C39-C47 ◽  
Author(s):  
Michael J. Porter ◽  
Maria C. Heidkamp ◽  
Brian T. Scully ◽  
Nehu Patel ◽  
Jody L. Martin ◽  
...  
Keyword(s):  
Gene Expression ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Ventricular Myocytes ◽  
Dominant Negative ◽  
Neonatal Rat ◽  
Mrna Levels ◽  
Rat Ventricular Myocytes ◽  
Kinase C ◽  
Neonatal Rat Ventricular Myocytes

Patients with cardiac hypertrophy and heart failure display abnormally slowed myocardial relaxation, which is associated with downregulation of sarco(endo)plasmic reticulum Ca2+-ATPase (SERCA2) gene expression. We previously showed that SERCA2 downregulation can be simulated in cultured neonatal rat ventricular myocytes (NRVM) by treatment with the protein kinase C (PKC) activator phorbol 12-myristate 13-acetate (PMA). However, NRVM express three different PMA-sensitive PKC isoenzymes (PKCα, PKCϵ, and PKCδ), which may be differentially regulated and have specific functions in the cardiomyocyte. Therefore, in this study we used adenoviral vectors encoding wild-type (wt) and kinase-defective, dominant negative (dn) mutant forms of PKCα, PKCϵ, and PKCδ to analyze their individual effects in regulating SERCA2 gene expression in NRVM. Overexpression of wtPKCϵ and wtPKCδ, but not wtPKCα, was sufficient to downregulate SERCA2 mRNA levels, as assessed by Northern blotting and quantitative, real-time RT-PCR (69 ± 7 and 61 ± 9% of control levels for wtPKCϵ and wtPKCδ, respectively; P < 0.05 for each adenovirus; n = 8 experiments). Conversely, overexpression of all three dnPKCs appeared to significantly increase SERCA2 mRNA levels (dnPKCδ > dnPKCϵ > dnPKCα). dnPKCδ overexpression produced the largest increase (2.8 ± 1.0-fold; n = 11 experiments). However, PMA treatment was still sufficient to downregulate SERCA2 mRNA levels despite overexpression of each dominant negative mutant. These data indicate that the novel PKC isoenzymes PKCϵ and PKCδ selectively regulate SERCA2 gene expression in cardiomyocytes but that neither PKC alone is necessary for this effect if the other novel PKC can be activated.

Adenosine A 1 Stimulation Activates δ-Protein Kinase C in Rat Ventricular Myocytes

1996 ◽  
Vol 78 (1) ◽  
pp. 161-165 ◽  
Author(s):  
Patrick Henry ◽  
Sophie Demolombe ◽  
Michel Pucéat ◽  
Denis Escande
Keyword(s):  
Protein Kinase C ◽  
Protein Kinase ◽  
Ventricular Myocytes ◽  
Rat Ventricular Myocytes ◽  
Kinase C

Protein kinase C-α-induced hypertrophy of neonatal rat ventricular myocytes

2004 ◽  
Vol 287 (6) ◽  
pp. H2777-H2789 ◽  
Author(s):  
Kalpana Vijayan ◽  
Erika L. Szotek ◽  
Jody L. Martin ◽  
Allen M. Samarel
Keyword(s):  
Protein Synthesis ◽  
Protein Kinase C ◽  
Protein Kinase ◽  
Nuclear Translocation ◽  
Ventricular Myocytes ◽  
Neonatal Rat ◽  
Rat Ventricular Myocytes ◽  
Kinase C ◽  
Infected Cells ◽  
Neonatal Rat Ventricular Myocytes

Protein kinase C (PKC) isoenzymes play a critical role in cardiomyocyte hypertrophy. At least three different phorbol ester-sensitive PKC isoenzymes are expressed in neonatal rat ventricular myocytes (NRVMs): PKC-α, -δ, and -ε. Using replication-defective adenoviruses (AdVs) that express wild-type (WT) and dominant-negative (DN) PKC-α together with phorbol myristate acetate (PMA), which is a hypertrophic agonist and activator of all three PKC isoenzymes, we studied the role of PKC-α in signaling-specific aspects of the hypertrophic phenotype. PMA induced nuclear translocation of endogenous and AdV-WT PKC-α in NRVMs. WT PKC-α overexpression increased protein synthesis and the protein-to-DNA (P/D) ratio but did not affect cell surface area (CSA) or cell shape compared with uninfected or control AdV β-galactosidase (AdV βgal)-infected cells. PMA-treated uninfected cells displayed increased protein synthesis, P/D ratio, and CSA and elongated morphology. PMA did not further enhance protein synthesis or P/D ratio in AdV-WT PKC-α-infected cells. To assess the requirement of PKC-α for these PMA-induced changes, AdV-DN PKC-α or AdV βgal-infected NRVMs were stimulated with PMA. Without PMA, AdV-DN PKC-α had no effects on protein synthesis, P/D ratio, CSA, or shape vs. AdV βgal-infected NRVMs. PMA increased protein synthesis, P/D ratio, and CSA in AdV βgal-infected cells, but these parameters were significantly reduced in PMA-stimulated AdV-DN PKC-α-infected NRVMs. Overexpression of DN PKC-α enhanced PMA-induced cell elongation. Neither WT PKC-α nor DN PKC-α affected atrial natriuretic factor gene expression. Insulin-like growth factor-1 also induced nuclear translocation of endogenous PKC-α. PMA but not WT PKC-α overexpression induced ERK1/2 activation. However, AdV-DN PKC-α partially blocked PMA-induced ERK activation. Thus PKC-α is necessary for certain aspects of PMA-induced NRVM hypertrophy.

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