Abstract P176: A New Function for Adipocytes: Norepinephrine Storage

• Published in: Hypertension (Dallas, Tex. 1979) Tex. 1979), 2017-09, Vol.70 (suppl_1)
• Main Authors: Ahmad, Maleeha, Ayala-Lopez, Nadia, Darios, Emma, Watts, Stephanie W
• Format: Article
• Language: English
• ISSN: 0194-911X; 1524-4563
• DOI: 10.1161/hyp.70.suppl_1.p176

Abstract only Activation of the sympathetic nervous system, and the subsequent release of the neurotransmitter norepinephrine (NE), contracts blood vessels and increases blood pressure, a mechanism altered in obesity-related hypertension. Perivascular adipose tissue (PVAT) is a functional reservoir for catecholamines, including NE, and PVAT adipocytes have plasma membrane transporters that can transport NE, pointing to similarities with the neuronal handling of NE. Thus, we hypothesize that PVAT adipocytes store NE, and use the vesicular monoamine transporter (VMAT) to do so, similar to sympathetic neurons. High-pressure liquid chromatography showed NE present in normal male Sprague Dawley rat superior mesenteric artery (SPVAT; 503.60 ± 34.70 ng mg tissue -1 ) and mesenteric (MPVAT; 148.20 ± 15.00 ng mg tissue -1 ) PVATs (N=6). Using immunofluorescence, we tested for VMAT1 and VMAT2 in these PVATs (N=6). Both transporters were present surrounding the lipid of the adipocytes. We developed a novel protocol imaging live primary rat MPVAT adipocytes to capture real-time uptake of Mini202, a fluorescent VMAT probe functioning as a false neurotransmitter (N=4). Cells stained with 500 μM Mini202 (Corrected Total Cell Fluorescence x 10^6 = 9.29 ± 0.88). Addition of 100 μM Rose Bengal, a potent VMAT inhibitor, eliminated Mini202 signal (CTCF x 10^6= -1.72 ± 0.30. Negative because Mini202 background brighter than abolished signal). These data support a new function of adipocytes in storing catecholamines. Understanding NE uptake and storage in PVAT is crucial for research on obesity-related hypertension and is important considering the growing prevalence of obesity and cardiovascular disease.