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Sympathetic overdrive in obesity involves purinergic hyperactivity in the resistance vasculature
Author(s) -
Haddock Rebecca Ellen,
Hill Caryl Elizabeth
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.26.1_supplement.lb603
Subject(s) - purinergic receptor , vasoconstriction , endocrinology , medicine , adrenergic , excitatory postsynaptic potential , neurotransmission , sympathetic nervous system , chemistry , inhibitory postsynaptic potential , blood pressure , adenosine , receptor
Diet‐induced obesity is associated with enhanced sympathetic outflow, as measured by release of noradrenaline. However, sympathetic nerves release other transmitters; ATP being especially important in control of vascular tone. Here we examined the purinergic and adrenergic components to nerve‐mediated vasoconstriction in small mesenteric arteries of Sprague‐Dawley rats fed a normal or high fat diet. Arteries were isolated, pressurised and smooth muscle membrane potential and vessel diameter measured in response to perivascular nerve stimulation. Innervation density was examined by histochemistry. Obesity increased the amplitude of nerve‐mediated vasoconstriction ( P <0.05; 1–10Hz). At 1 and 5Hz, purinergic and adrenergic responses were augmented, while only the purinergic component was increased at 10Hz ( P <0.05). Vasoconstriction at 1Hz in obesity was associated with larger purinergic excitatory junction potentials ( P <0.05), exhibiting decreased rise time and rate of decay ( P <0.05), without change in resting membrane potential. Spontaneous EJPs were also significantly increased in amplitude and frequency, as was the density of the sympathetic nerve plexus ( P < 0.05). We demonstrate that sympathetic nerve‐mediated vasoconstriction is enhanced by obesity due to upregulation of purinergic, in addition to adrenergic, neurotransmission. The study was supported by the NHMRC to REH (466009).