Abstract |
The prostanoid thromboxane A2 has been implicated to contribute to the pathogenesis of many cardiovascular diseases, including hypertension. To study the role of vascular thromboxane- prostanoid ( TP) receptors in blood pressure regulation, we generated mice with cell-specific deletion of TP receptors in smooth muscle using Cre/Loxp technology. We crossed the KISM22α-Cre transgenic mouse line expressing Cre recombinase in smooth muscle cells with a mouse line bearing a conditional allele of the Tbxa2r gene (Tp(flox)). In KISM22α-Cre(+)Tp(flox/flox) (TP-SMKO) mice, TP receptors were efficiently deleted from vascular smooth muscle cells. In TP-SMKOs, acute vasoconstrictor responses to the TP agonist U46619 were attenuated to a similar extent in both the peripheral and renal circulations. Yet, acute vascular responses to angiotensin II were unaffected at baseline and after chronic angiotensin II administration. Infusion of high-dose U46619 caused circulatory collapse and death in a majority of control mice but had negligible hemodynamic effects in TP-SMKOs, which were completely protected from U46619-induced sudden death. Baseline blood pressures were normal in TP-SMKOs. However, the absence of TP receptors in vascular smooth muscle cells was associated with significant attenuation of angiotensin II-induced hypertension and diminished vascular remodeling. This was also associated with reduced urinary thromboxane production after chronic angiotensin II. Thus, TP receptors in vascular smooth muscle cells play a major role in mediating the actions of thromboxane A(2) in TP agonist-induced shock, hypertension, and vascular remodeling of the aorta.
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Authors | Matthew A Sparks, Natalia A Makhanova, Robert C Griffiths, John N Snouwaert, Beverly H Koller, Thomas M Coffman |
Journal | Hypertension (Dallas, Tex. : 1979)
(Hypertension)
Vol. 61
Issue 1
Pg. 166-73
(Jan 2013)
ISSN: 1524-4563 [Electronic] United States |
PMID | 23150508
(Publication Type: Journal Article, Research Support, Non-U.S. Gov't)
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Chemical References |
- Receptors, Thromboxane
- Vasoconstrictor Agents
- Thromboxane A2
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
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Topics |
- 15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5,13-dienoic Acid
(pharmacology)
- Animals
- Aorta
(drug effects, metabolism)
- Blood Pressure
(drug effects)
- Death, Sudden
- Hypertension
(genetics, metabolism)
- Mice
- Mice, Knockout
- Muscle, Smooth, Vascular
(drug effects, metabolism)
- Myocytes, Smooth Muscle
(drug effects, metabolism)
- Receptors, Thromboxane
(genetics, metabolism)
- Thromboxane A2
(pharmacology)
- Vasoconstriction
(drug effects)
- Vasoconstrictor Agents
(pharmacology)
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