Regional activation of rapid onset vasodilatation in mouse skeletal muscle: regulation through ýý-adrenoreceptors.
Regional activation of rapid onset vasodilatation in mouse skeletal muscle: regulation through ýý-adrenoreceptors.
复制标题
小鼠骨骼肌快速血管舒张的区域激活：通过 α-肾上腺素受体进行调节。
DOI：
10.1113/jphysiol.2010.193672
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发表时间：
2010
期刊：
影响因子：
--
通讯作者：
Segal,StevenS
中科院分区：
文献类型：
--
作者：
Moore,AlexW;Bearden,ShawnE;Segal,StevenS
Exercise onset entails motor unit recruitment and the initiation of vasodilatation. Dilatation can ascend the arteriolar network to encompass proximal feed arteries but is opposed by sympathetic nerve activity, which promotes vasoconstriction and inhibits ascending vasodilatation through activating α‐adrenoreceptors. Whereas contractile activity can antagonize sympathetic vasoconstriction, more subtle aspects of this interaction remain to be defined. We tested the hypothesis that constitutive activation of α‐adrenoreceptors governs blood flow distribution within individual muscles. The mouse gluteus maximus muscle (GM) consists of Inferior and Superior regions. Each muscle region is supplied by its own motor nerve and feed artery with an anastomotic arteriole (resting diameter ∼25 μm) that spans both muscle regions. In anaesthetized male C57BL/6J mice (3–5 months old), the GM was exposed and superfused with physiological saline solution (35°C; pH 7.4). Stimulating the inferior gluteal motor nerve (0.1 ms pulse, 100 Hz for 500 ms) evoked a brief tetanic contraction and produced rapid (<1 s) onset vasodilatation (ROV; diameter change, 10 ± 1 μm) of the anastomotic arteriole along the active (Inferior) muscle region but not along the inactive (Superior) region (n= 8). In contrast, microiontophoresis of acetylcholine (1 μm micropipette tip, 1 μA, 500 ms) initiated dilatation that travelled along the anastomotic arteriole from the Inferior into the Superior muscle region (diameter change, 5 ± 2 μm). Topical phentolamine (1 μm) had no effect on resting diameter but this inhibition of α‐adrenoreceptors enabled ROV to spread along the anastomotic arteriole into the inactive muscle region (dilatation, 7 ± 1 μm;P< 0.05), where remote dilatation to acetylcholine then doubled (P< 0.05). These findings indicate that constitutive activation of α‐adrenoreceptors in skeletal muscle can restrict the spread of dilatation within microvascular resistance networks and thereby increase blood flow to active muscle regions.
