Stimulation of β1- and β2-adrenoceptors dilates retinal blood vessels in rats
Stimulation of β1- and β2-adrenoceptors dilates retinal blood vessels in rats
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DOI：
10.1007/s00210-017-1349-4
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发表时间：
2017-05-01
影响因子：
3.6
通讯作者：
Nakahara, Tsutomu
中科院分区：
文献类型：
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作者：
Mori, Asami;Sekito, Akane;Nakahara, Tsutomu
我们以前的研究表明，肾上腺素通过刺激心得安敏感的β-肾上腺素受体和β(3)-肾上腺素能受体来扩张大鼠视网膜小动脉，选择性刺激β(2)-或β(3)-肾上腺素能受体引起视网膜血管扩张反应。在本研究中，我们比较了刺激β(1)和β(2)肾上腺素能受体对在体大鼠视网膜小动脉的影响。使用原始的高分辨率数字眼底相机拍摄大鼠眼底图像。测量图像中视网膜小动脉的直径。连续记录全身血压和心率。地诺帕明是一种β(1)-肾上腺素能受体激动剂，它增加了视网膜小动脉的直径和心率，并使平均动脉压略有下降，但在统计学上并不显著。β(1)-肾上腺素能受体拮抗剂CGP20712A可显著抑制地诺帕明诱导的视网膜血管扩张剂和心率反应，而β(2)-肾上腺素能受体拮抗剂ICI118551则不能。沙丁胺醇是一种β(2)-肾上腺素能受体激动剂，它增加了视网膜小动脉的直径，降低了平均动脉压，但没有显著改变心率。ICI118551可显著抑制沙丁胺醇的作用，而CGP20712A则不能。这些结果表明，刺激β(1)和β(2)-肾上腺素能受体扩张视网膜血管，提示所有三种β-受体亚型(β(1)、β(2)和β(3))都可能参与大鼠视网膜血管扩张剂对肾上腺素的反应。
Our previous studies have demonstrated that adrenaline dilates rat retinal arterioles by stimulating propranolol-sensitive beta-adrenoceptors and beta(3)-adrenoceptors, and selective stimulation of beta(2)- or beta(3)-adrenoceptors causes retinal vasodilator responses. In the present study, we compared the effects of beta(1)- and beta(2)-adrenoceptor stimulation on rat retinal arterioles in vivo. Rat ocular fundus images were captured using an original high-resolution digital fundus camera. Diameters of retinal arterioles contained in the images were measured. Systemic blood pressure and heart rate were recorded continuously. Denopamine, a beta(1)-adrenoceptor agonist, increased the diameter of retinal arterioles and heart rate, and produced a small but statistically insignificant decrease in mean arterial pressure. CGP20712A, a beta(1)-adrenoceptor antagonist, but not ICI118551, a beta(2)-adrenoceptor antagonist, significantly prevented denopamine-induced retinal vasodilator and heart rate responses. Salbutamol, a beta(2)-adrenoceptor agonist, increased the diameter of retinal arterioles and decreased mean arterial pressure without significantly changing heart rate. The effects of salbutamol were significantly prevented by ICI118551, but not by CGP20712A. These results suggest that stimulation of beta(1)- and beta(2)-adrenoceptors dilates retinal blood vessels and indicate that all three beta-adrenoceptor subtypes (beta(1), beta(2), and beta(3)) may be involved in the retinal vasodilator response to adrenaline in rats.