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- Title
Adenosine elicits an eNOS-independent reduction in arterial blood pressure in conscious mice that involves adenosine A<sub>2A</sub> receptors.
- Authors
Andersen, H.; Jaff, M. G.; Høgh, D.; Vanhoutte, P.; Hansen, P. B.
- Abstract
Aims: Adenosine plays an important role in the regulation of heart rate (HR) and vascular reactivity. However, the mechanisms underlying the acute effect of adenosine on arterial blood pressure in conscious mice are unclear. Therefore, this study investigated the effect of the nucleoside on mean arterial blood pressure (MAP) and HR in conscious mice. Methods: Chronic indwelling catheters were placed in C57Bl/6J (WT) and endothelial nitric oxide synthase knockout (eNOS−/−) mice for continuous measurements of MAP and HR. Using PCR and myograph analysis, involvement of adenosine receptors was investigated in human and mouse renal blood vessels. Results: Bolus infusion of 0.5 mg kg−1 adenosine elicited significant transient decreases in MAP (99.3 ± 2.3 to 70.4 ± 4.5 mmHg) and HR (603.2 ± 18.3 to 364.3 ± 49.2 min−1), which were inhibited by the A2A receptor antagonist ZM 241385. Activation of adenosine A2A receptors with CGS 21680 (0.02 mg kg−1) caused a significant reduction in MAP from 99.6 ± 1.2 to 73.1 ± 3.6 mmHg accompanied by tachycardia (610.5 ± 9.3 to 677.5 ± 9.5 min−1). The reduction in MAP observed after adenosine or CGS 21680 administrations was not significantly different in WT and eNOS−/− mice. In isolated human and mouse intrarenal arteries, adenosine caused a relaxation dependent on A2A adenosine receptor activation. A2A receptors were present in both human and mouse arteries whereas A1 and A2B receptors were only present in mouse arteries. Conclusion: In conclusion, acute adenosine administration and selective stimulation of adenosine A2A receptors results in an immediate, transient eNOS-independent reduction in MAP. A2A receptor activation causes relaxation of human and mouse arteries.
- Subjects
ADENOSINES; CARDIOVASCULAR receptors; HEART beat; REGULATION of blood pressure; BLOOD-vessel abnormalities; POLYMERASE chain reaction; LABORATORY mice; PHYSIOLOGY
- Publication
Acta Physiologica, 2011, Vol 203, Issue 1, p197
- ISSN
1748-1708
- Publication type
Article
- DOI
10.1111/j.1748-1716.2010.02218.x