| 17617391 |
Fesus G, Dubrovska G, Gorzelniak K, Kluge R, Huang Y, Luft FC, Gollasch M: Adiponectin is a novel humoral vasodilator. Cardiovasc Res. 2007 Sep 1;75(4):719-27. Epub 2007 Jun 6.
OBJECTIVES: Perivascular adipose tissue secretes an adipocyte-derived relaxing factor (s) (ADRF) that opens K (v) channels in rat arteries. Visceral fat accumulation causes adipocyte dysfunction, including hyposecretion of adiponectin. We tested the hypothesis that ADRF might be adiponectin and that adiponectin plays a role in the paracrine control of vascular tone by perivascular adipose tissue. METHODS AND RESULTS: We studied Sprague-Dawley rats, wild-type and adiponectin gene-deficient (Apn 1-/-) mice, and New Zealand obese (NZO) mice. In rat aortas, recombinant adiponectin at serum levels (2-5 microg/ml) inhibited serotonin-induced contractions. The effects were abolished by K (v) channel inhibition with 4-aminopyridine (4-AP, 2 mM). Similar effects were observed in NZO mouse mesenteric arteries. To study vascular function in Apn 1-/- mice, the mesenteric vascular bed was isolated, cannulated, and perfused at a constant 4-5-ml/min flow in the absence and presence of serotonin. 4-AP (2 mM) induced a similar increase in perfusion pressure in the Apn 1-/- perfused isolated mesenteric vascular bed, compared to wild-type mice. Removal of perivascular fat increased the vasoconstrictor responses, but abolished the 4-AP effects. The anti-contractile effects of perivascular fat were similar in mesenteric artery and aortic rings from Apn 1-/- and wild-type mice. Despite high adiponectin levels, the anti-contractile effects of perivascular fat were diminished in mesenteric arteries of NZO mice with age. CONCLUSION: Adiponectin is a novel humoral vasodilator that relaxes aortic and mesenteric rings by opening K (v) channels. Similar to the rat, perivascular adipose tissue of the mouse harbors an ADRF, which is malfunctional in NZO mice and is not adiponectin. |
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