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Peripheral macrophage depletion impairs phenylephrine mediated contraction in aorta from stroke prone spontaneously hypertensive rats, but does not alter the effect of perivascular fat
Author(s) -
Dorrance Anne McLaren,
Pires Paulo Wagner,
McClain Jonathon Lee,
Watts Stephanie W
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.872.4
Subject(s) - contraction (grammar) , medicine , phenylephrine , aorta , endocrinology , myograph , peripheral , isometric exercise , vascular smooth muscle , blood pressure , cardiology , smooth muscle
Perivascular fat limits contraction in isolated aortic rings. These studies have been largely conducted in normotensive rats. We proposed that perivascular fat would impair contraction in aorta from stroke prone spontaneously hypertensive rats (SHSRP) and that peripheral macrophage depletion would exacerbate this impairment. SHRSP were treated with liposome‐encapsulated clodronate (CLOD) or placebo for six weeks from six weeks of age to remove the peripheral macrophages. Aortae where then removed and mounted in a wire myograph to measure isometric force generation with and without perivascular fat. CLOD had no effect on blood pressure (201±7 vs 200±5 mmHg, control vs CLOD) or body weight (251±7 vs 248±3g, control vs CLOD). The phenylephrine (PE) induced contraction was impaired in the aorta + fat from control SHRSP. Interestingly, macrophage ablation reduced the PE mediated contraction in the clean aorta but not in the aorta + fat. The KCl induced contraction was also reduced in the presence of fat in both groups. These results suggest that macrophage deletion has direct effects on the vascular smooth muscle to reduce contraction.Control (n=5) Control+Fat CLOD (n=6) CLOD+FatMax PE contraction (% of KCl) 85.3±5.2 65.9±4.8 * 71.3±2.4 * 59.2±3.1 EC50 −7.7±0.2 −6.7±0.1 * −7.3±0.2 −6.7±0.2 KCl induced contraction (mN) 23.5±1.6 14.4±0.2 * 30.0±1.8 16.1±1.7 #* different from Control.# different from CLOD