Reduced anti-contractile effect of perivascular adipose tissue on mesenteric small arteries from spontaneously hypertensive rats: role of Kv7 channels.
Perivascular adipose tissue (PVAT) has been shown to produce vasoactive substances and regulate vascular tone. This function of PVAT has been reported to be altered in hypertension. However, the underlying mechanisms are not fully understood. In this study we used age-matched normotensive Wistar-Kyoto (WKY) rats and spontaneously hypertensive rats (SHR) as well as Sprague-Dawley rats and tested effects of PVAT on mesenteric small arteries. Vessels were mounted in a Mulvany-Halpern myograph and cumulative concentration-response relations to noradrenaline were determined in the presence or absence of PVAT. We found that PVAT has an anti-contractile effect on mesenteric small vessels, irrespective of strains. A reduced effect of PVAT was observed in SHR compared to WKY rats; the difference between strains was eliminated by 10 μM XE991, a blocker of Kv7 (KCNQ) voltage-dependent potassium channels. The anti-contractile effect of PVAT was not affected by depolarizing smooth muscle cells with high K(+) solution. Sensitivities to exogenous vasodilators acetylcholine or sodium nitroprusside were not potentiated but reduced in vessels with PVAT. Our results suggest that the reduced anti-contractile effect of PVAT in SHR correlates with a deficiency in Kv7 channels. Diffusion hindrance of PVAT is also a factor that should be considered in investigations on rat mesenteric small arteries.
Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, PO Box 432, S-40530 Gothenburg, Sweden. rui.li@gu.se
Rui
R
Li
Ingrid
I
Andersen
Josefin
J
Aleke
Veronika
V
Golubinskaya
Helena
H
Gustafsson
Holger
H
Nilsson
D000273:Adipose Tissue / Q000166:cytology*; D000818:Animals; D000873:Anthracenes / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002395:Catecholamines / Q000378:metabolism; D004058:Diffusion; D066298:In Vitro Techniques; D051656:KCNQ Potassium Channels / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008297:Male; D008638:Mesenteric Arteries / Q000166:cytology* / Q000378:metabolism / Q000502:physiology*; D051381:Rats; D011918:Rats, Inbred SHR; D014661:Vasoconstriction / Q000187:drug effects
C112297:10,10-bis(4-pyridinylmethyl)-9(10H)-anthracenone; D000873:Anthracenes; D002395:Catecholamines; D051656:KCNQ Potassium Channels