Abstract P627: The β3 Adrenergic Receptor is Partially Responsible for Anti-contractile Effect of Perivascular Adipose Tissue in Rat Mesenteric Resistance Arteries
In normal conditions, perivascular adipose tissue (PVAT) decreases contractile responses non-specifically in various vascular beds. This anti-contractile effect of PVAT is reduced in metabolic diseases and hypertension. The β3 adrenergic receptor (β3AR) is a G protein-coupled receptor expressed in adipocytes and involved in lipolysis and thermoregulation. We have previously demonstrated that chronic systemic infusion with a β3AR agonist induces white-to-brown adipose tissue remodeling and enhanced anti-contractile effects of PVAT via activation of cystathionine gamma lyase, enzyme involved in hydrogen sulfide synthesis. We hypothesized that the β3AR is directly mediating release of PVAT relaxing factors. Endothelium-intact mesenteric resistance arteries from adult male Wistar rats were used to measure contractile responses in the presence and absence of PVAT. In the absence of PVAT, the β3AR agonist CL316243 (1 nM-10 μM) did not directly induce relaxation of U46619-contracted arteries. In control conditions, norepinephrine (NE)-induced contraction was significantly reduced in the presence of PVAT. In contrast, incubation with the selective β3AR antagonist L-748337 (100 nM) led to a significant increase in NE-induced contraction in PVAT-intact arteries, while no change was observed in the absence of PVAT (figure). These data suggest that β3AR mediates the anti-contractile effect of PVAT on NE-induced contraction in resistance mesenteric arteries. Considering the structural and functional alterations of PVAT in hypertension, future studies may reveal a potential novel therapeutic approach via targeting of the PVAT β3AR pathway.
Author Disclosures: T. Szasz: None. T. Matsumoto: None. C.F. Wenceslau: None. R. Webb: None.
- © 2015 by American Heart Association, Inc.