scholarly journals The Effect of alpha-Tocopherol on the Synthesis, Phosphorylation and Activity of Protein Kinase C in Smooth Muscle Cells After Phorbol 12-Myristate 13-Acetate Down-Regulation

1997 ◽  
Vol 246 (3) ◽  
pp. 745-749 ◽  
Author(s):  
Sophie Clement ◽  
Andrea Tasinato ◽  
Daniel Boscoboinik ◽  
Angelo Azzi
1989 ◽  
Vol 262 (1) ◽  
pp. 285-291 ◽  
Author(s):  
J Pfeilschifter ◽  
M Ochsner ◽  
S Whitebread ◽  
M De Gasparo

In smooth-muscle cells (SMC) isolated from rat aorta, angiotensin II stimulates a phospholipase C with subsequent formation of inositol trisphosphate (InsP3). Short-term (10 min) pretreatment of SMC with 12-O-tetradecanoylphorbol 13-acetate (TPA; 100 nM) decreases the angiotensin II-induced InsP3 formation. However, this inhibition is not observed after incubating the cells for 2 h with TPA. Longer-term pretreatments even lead to an enhanced generation of InsP3. This increased response to angiotensin II occurs without a significant change in the receptor number or Kd value of angiotensin II binding to the cells. The biologically inactive phorbol ester 4 alpha-phorbol 12,13-didecanoate was without effect on angiotensin II-stimulated InsP3 generation, irrespective of the time of preincubation. In parallel with this potentiation of angiotensin II-induced generation of InsP3 by TPA, a down-regulation of protein kinase C activity is observed. A 24 h pretreatment of SMC with TPA decreases protein kinase C activity to less than 10% of that of control cells. Longer-term pretreatment also increases the angiotensin II-induced release of Ca2+ and delays the decay of the transient Ca2+ increase. All these data suggest that protein kinase C exerts a negative feedback control on angiotensin II-stimulated polyphosphoinositide turnover, and that protein kinase C is an important factor in limiting the production of InsP3 in stimulated cells.


1997 ◽  
Vol 17 (5) ◽  
pp. 969-978 ◽  
Author(s):  
Michele Mietus-Snyder ◽  
Annabelle Friera ◽  
Christopher K. Glass ◽  
Robert E. Pitas

1987 ◽  
Vol 173 (2) ◽  
pp. 504-514 ◽  
Author(s):  
Ken-Ichi Kariya ◽  
Yasuo Fukumoto ◽  
Terutaka Tsuda ◽  
Takeshi Yamamoto ◽  
Yasuhiro Kawahara ◽  
...  

2013 ◽  
Vol 2013 ◽  
pp. 1-11 ◽  
Author(s):  
Jie Li ◽  
Lei Cao ◽  
Cang-Bao Xu ◽  
Jun-Jie Wang ◽  
Yong-Xiao Cao

Minimally modified low-density lipoprotein (mmLDL) is a risk factor for cardiovascular disease. The present study investigated the effects of mmLDL on the expression of endothelin type A () receptors in coronary arteries. Rat coronary arteries were organ-cultured for 24 h. The contractile responses were recorded using a myographic system. receptor mRNA and protein expressions were determined using real-time PCR and western blotting, respectively. The results showed that organ-culturing in the presence of mmLDL enhanced the arterial contractility mediated by the receptor in a concentration-dependent and time-dependent manner. Culturing with mmLDL (10 μg/mL) for 24 h shifted the concentration-contractile curves toward the left significantly with increased of from control of and significantly increased receptor mRNA and protein levels. Inhibition of the protein kinase C, extracellular signal-related kinases 1 and 2 (ERK1/2), or NF-κB activities significantly attenuated the effects of mmLDL. The c-Jun N-terminal kinase inhibitor or the p38 pathway inhibitor, however, had no such effects. The results indicate that mmLDL upregulates the receptors in rat coronary arterial smooth muscle cells mainlyviaactivating protein kinase C, ERK1/2, and the downstream transcriptional factor, NF-κB.


1993 ◽  
Vol 265 (6) ◽  
pp. C1723-C1728 ◽  
Author(s):  
A. D. Bonev ◽  
M. T. Nelson

We explored the possibility that muscarinic receptor stimulation can inhibit ATP-sensitive K+ (KATP) channels in smooth muscle cells from guinea pig urinary bladder. Whole cell K+ currents were measured in smooth muscle cells isolated from the detrusor muscle of the guinea pig bladder. Stimulation of muscarinic receptors by carbachol (CCh; 10 microM) inhibited KATP currents by 60.7%. Guanosine 5'-O-(2-thiodiphosphate) in the pipette (internal) solution prevented the CCh-induced inhibition of KATP currents. Activators of protein kinase C (PKC), a diacylglycerol analogue, and phorbol 12-myristate 13-acetate inhibited KATP currents by 63.5 and 73.9%, respectively. Blockers of PKC (bisindolylmaleimide GF-109203X and calphostin C) greatly reduced CCh inhibition of KATP currents. We propose that muscarinic receptor stimulation inhibits KATP channels in smooth muscle cells from urinary bladder through activation of PKC.


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