Koizumi Ryo, Fushimi Taiki, Sato Yuki, Fujii Yasuyuki, Sato Hiroki, Osakabe Naomi
Department of Bio-science and Engineering, Shibaura Institute of Technology, Saitama, Japan.
Free Radic Res. 2021 May;55(5):491-498. doi: 10.1080/10715762.2020.1759805. Epub 2021 Jul 12.
We previously found that a single dose of B-type procyanidin mixture increase in skeletal muscle blood flow (BF). We compared BF changes following administration of (-)-epicatechin (EC, monomer) and the B-type procyanidins procyanidin B2 (B2, dimer), procyanidin C1 (C1, trimer), and cinnamtannin A2 (A2, tetramer). Each chemical was administered orally to rats, followed by BF measurement in cremaster arteriole for 60 min. About 10 and 100 µg/kg of B2 and C1 elicited BF increase, the effect was potent at 100 µg/kg. BF also increased significantly after administration of 10 µg/kg A2, but not with the administration at 100 µg/kg. EC yielded no BF changes. Co-treatment with the nonselective adrenaline blocker carvedilol attenuated the BF increase seen with 10 µg/kg A2 treatment. This outcome suggested the involvement of sympathetic nerve activation in the BF increase by this dose of A2. Co-treatment of 100 µg/kg A2 with the α2 blocker yohimbine exhibited an increase of BF significantly. The α2 adrenaline receptor in the vasomotor centre is an inhibitory receptor and it regulates hemodynamics. This result suggested that high doses of A2 did not alter BF because of activating the α2 adrenergic receptor. Phosphorylation of aortic endothelial nitric oxide synthase (eNOS) increased with 10 µg/kg A2 alone or co-treatment with 100 µg/kg A2 and yohimbine, but not with co-treatment of 10 µg/kg A2 and carvedilol or 100 µg/kg A2 alone. These results imply that A2 does not directly activate eNOS, but that shear stress from the increased BF might be associated with eNOS phosphorylation.
我们之前发现，单剂量的B型原花青素混合物可增加骨骼肌血流量（BF）。我们比较了给予（-）-表儿茶素（EC，单体）以及B型原花青素原花青素B2（B2，二聚体）、原花青素C1（C1，三聚体）和肉桂单宁A2（A2，四聚体）后BF的变化。将每种化学物质口服给予大鼠，随后在提睾小动脉中测量BF 60分钟。约10和100μg/kg的B2和C1可引起BF增加，在100μg/kg时作用较强。给予10μg/kg A2后BF也显著增加，但100μg/kg时未增加。EC未引起BF变化。与非选择性肾上腺素阻滞剂卡维地洛联合治疗可减弱10μg/kg A2治疗时出现的BF增加。这一结果表明，交感神经激活参与了该剂量A2引起的BF增加。100μg/kg A2与α2阻滞剂育亨宾联合治疗时BF显著增加。血管运动中枢的α2肾上腺素受体是一种抑制性受体，它调节血流动力学。这一结果表明，高剂量A2未改变BF是因为激活了α2肾上腺素能受体。单独使用10μg/kg A2或与100μg/kg A2和育亨宾联合治疗时，主动脉内皮型一氧化氮合酶（eNOS）的磷酸化增加，但与10μg/kg A2和卡维地洛联合治疗或单独使用100μg/kg A2时未增加。这些结果表明，A2不会直接激活eNOS，但增加的BF产生的剪切应力可能与eNOS磷酸化有关。
