Extracellular calcium sensing in rat aortic vascular smooth muscle cells

2006 ◽  
Vol 348 (4) ◽  
pp. 1215-1223 ◽  
Author(s):  
Sanela Smajilovic ◽  
Jakob Lerche Hansen ◽  
Tue E.H. Christoffersen ◽  
Ewa Lewin ◽  
Søren P. Sheikh ◽  
...  
2008 ◽  
Vol 81 (2) ◽  
pp. 260-268 ◽  
Author(s):  
Masih-ul Alam ◽  
John Paul Kirton ◽  
Fiona L. Wilkinson ◽  
Emily Towers ◽  
Smeeta Sinha ◽  
...  

2017 ◽  
Vol 35 (3) ◽  
pp. 523-532 ◽  
Author(s):  
Ioana Alesutan ◽  
Rashad Tuffaha ◽  
Tilman Auer ◽  
Martina Feger ◽  
Burkert Pieske ◽  
...  

1994 ◽  
Vol 304 (2) ◽  
pp. 543-548 ◽  
Author(s):  
E J Freeman ◽  
E A Tallant

We previously showed that angiotensin II (Ang II) and angiotensin-(2-8)-peptide [Ang-(2-8)] activate a phosphoinositide-specific phospholipase C (PLC) and cause calcium mobilization in rat aortic vascular smooth-muscle cells (VSMC), while Ang II and Ang-(1-7) produce prostaglandins. To define further the signal-transduction mechanisms activated by angiotensin peptides in smooth-muscle cells, we measured diacylglycerol (DAG) accumulation in response to different angiotensin peptides and its inhibition by subtype-selective receptor antagonists. Both an initial (10 s) and secondary (10 min) phase of DAG production in response to 100 nM Ang II were inhibited by 1 microM losartan (DuP 753), an AT1 antagonist, while 1 microM PD 123177, an AT2 antagonist, was ineffective. In contrast, the heptapeptide Ang-(1-7) did not produce DAG in VSMC. Ang II also caused the hydrolysis of phosphatidylinositol and phosphatidylcholine, the formation of phosphatidic acid and the formation of phosphatidylethanol (PEt) in the presence of ethanol, through activation of a PLD and a PLD-induced transphosphatidylation reaction. A similar concentration of Ang-(2-8) also activated PLD; in contrast, Ang-(1-7) was ineffective. PEt production by 100 nM Ang II was significantly attenuated by the AT1 antagonists losartan, its metabolite EXP 3174 or L-158,809 (all at 1 microM), whereas a similar concentration of the AT2 antagonists CGP 42112A or PD 123177 was ineffective. The production of PEt by Ang II was also partially attenuated by the removal of extracellular calcium and potentiated by increasing calcium concentrations, indicating that PLD activity is partially dependent on extracellular calcium. Thus VSMC PLD is coupled to an AT1 receptor and occurs in response to Ang II or Ang-(2-8), but not Ang-(1-7). Since AT1 receptors in VSMC are also coupled to activation of PLC, both PLC and PLD may be coupled to the same or a different AT1 receptor. Alternatively, PLD may be sequentially activated in response to Ang II activation of PLC and a subsequent increase in calcium concentration.


2016 ◽  
Vol 310 (3) ◽  
pp. C193-C204 ◽  
Author(s):  
M. Schepelmann ◽  
P. L. Yarova ◽  
I. Lopez-Fernandez ◽  
T. S. Davies ◽  
S. C. Brennan ◽  
...  

The extracellular calcium-sensing receptor CaSR is expressed in blood vessels where its role is not completely understood. In this study, we tested the hypothesis that the CaSR expressed in vascular smooth muscle cells (VSMC) is directly involved in regulation of blood pressure and blood vessel tone. Mice with targeted CaSR gene ablation from vascular smooth muscle cells (VSMC) were generated by breeding exon 7 LoxP-CaSR mice with animals in which Cre recombinase is driven by a SM22α promoter (SM22α-Cre). Wire myography performed on Cre-negative [wild-type (WT)] and Cre-positive SM22αCaSRΔflox/Δflox [knockout (KO)] mice showed an endothelium-independent reduction in aorta and mesenteric artery contractility of KO compared with WT mice in response to KCl and to phenylephrine. Increasing extracellular calcium ion (Ca2+) concentrations (1–5 mM) evoked contraction in WT but only relaxation in KO aortas. Accordingly, diastolic and mean arterial blood pressures of KO animals were significantly reduced compared with WT, as measured by both tail cuff and radiotelemetry. This hypotension was mostly pronounced during the animals' active phase and was not rescued by either nitric oxide-synthase inhibition with nitro-l-arginine methyl ester or by a high-salt-supplemented diet. KO animals also exhibited cardiac remodeling, bradycardia, and reduced spontaneous activity in isolated hearts and cardiomyocyte-like cells. Our findings demonstrate a role for CaSR in the cardiovascular system and suggest that physiologically relevant changes in extracellular Ca2+ concentrations could contribute to setting blood vessel tone levels and heart rate by directly acting on the cardiovascular CaSR.


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