Artikel
Perivascular adipose tissue and mesenteric vascular function in spontaneously hypertensive rats (SHR)
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Veröffentlicht: | 10. August 2005 |
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Gliederung
Text
Perivascular adipose tissue produces leptin and induces vasorelaxation by opening of 4-aminopyridine (4-AP)-sensitive K+ channels in normotensive rats. We have characterized the mesenteric perivascular adipose tissue from 3-month-old Wistar Kyoto (WKY) and aged-matched spontaneously hypertensive rats (SHR) and have tested the hypothesis that this tissue contributes to differences in vascular resistance in hypertension. Mesenteric bed (MB) weight as well as MB total lipid content were lower in SHR than in WKY rats. Freshly isolated MB adipocytes were similar in size between strains. Plasma tryglicerides, glycerol, non-esterified free-fatty acids, and leptin were also lower in SHR than in WKY rats. There was a significant correlation between leptin content and the quantity of mesenteric fat. In order to study vascular function, the MB was cannulated and perfused at a constant flow of 2 ml/min. 4-AP (2 mM) induced a smaller increase in perfusion pressure in MB of SHR rats compared to WKY rats. In isolated mesenteric artery rings, 4-AP (2 mM) induced a contractile effect that was significantly reduced in SHR compared to WKY rats. The anti-contractile effects of perivascular fat were smaller in mesenteric artery rings from SHP rats than from WKY rats. These results suggest that the lower content of perivascular adipose tissue and leptin in SHR might contribute to the increased vascular resistance in this strain. Supported by MCyT (BFI 2001-0638) and DFG.