Delgado Esmeralda, Marques-Neves Carlos, Rocha Isabel, Sales-Luís José, Silva-Carvalho Luis
Clinical Department, Centre for Interdisciplinary Investigation into Animal Health, Faculty of Veterinary Medicine, Technical University of Lisbon, Lisbon, Portugal.
Acta Ophthalmol. 2009 Jun;87(4):443-9. doi: 10.1111/j.1755-3768.2008.01285.x. Epub 2008 Aug 14.
We aimed to investigate the responsiveness of the ocular arteries to adrenergic drugs in a model of perfused isolated rabbit eye.
Rabbit external ophthalmic arteries (n = 15) in a head-mounted preparation were cannulated and the retinal and uveal vasculature perfused at a constant flow with warmed tyrode. The three-way polypropylene catheter was further connected to a pressure transducer and intraluminal pressure was taken as a measure of vascular resistance. Effects of intra-arterial injections of phenylephrine (group A, n = 5), prazosin (group B, n = 5) and phentolamine (group C, n = 5) on the recorded pressure were obtained. Student's paired-t test and one-way analysis of variance were used for statistical analysis (p < 0.05).
Intrinsic vasomotricity was observed in all preparations prior to any drug administration. Phenylephrine produced an increase in total vascular resistance. Intrinsic vasomotricity became more evident, showing a lower frequency but higher amplitude of oscillations. Evoked vasomotor responses with phenylephrine (250 microg/ml) were inhibited by intra-arterial administration of the selective alpha(1)-adrenergic antagonist, prazosin (0.5 mg/ml), as well as the non-selective alpha-adrenergic antagonist phentolamine (6 mg/ml).
Rabbit external ophthalmic arteries showed spontaneous contractions under constant perfusion. Phenylephrine elicited a vasoconstrictor response that was inhibited by adrenergic antagonists. In addition, the intrinsic vasomotricity was enhanced by phenylephrine and blocked by adrenergic antagonists. These results show that under in vitro perfusion the territory presents similar responses to adrenergic drugs to those observed in in vivo models and also provides evidence of myogenic autoregulatory properties in the rabbit ophthalmic artery and/or choroid.
我们旨在研究在灌注离体兔眼模型中眼动脉对肾上腺素能药物的反应性。
将15只兔的眼外动脉在头部固定的标本中插管，并以恒定流量用温热的台氏液灌注视网膜和葡萄膜血管系统。三通聚丙烯导管进一步连接到压力传感器，管腔内压力作为血管阻力的指标。获得动脉内注射去氧肾上腺素（A组，n = 5）、哌唑嗪（B组，n = 5）和酚妥拉明（C组，n = 5）对记录压力的影响。采用学生配对t检验和单因素方差分析进行统计分析（p < 0.05）。
在给予任何药物之前，在所有标本中均观察到内在血管运动性。去氧肾上腺素使总血管阻力增加。内在血管运动性变得更加明显，显示出较低的频率但较高的振荡幅度。动脉内给予选择性α(1)-肾上腺素能拮抗剂哌唑嗪（0.5 mg/ml）以及非选择性α-肾上腺素能拮抗剂酚妥拉明（6 mg/ml）可抑制去氧肾上腺素（250 μg/ml）诱发的血管运动反应。
兔眼外动脉在恒定灌注下表现出自发性收缩。去氧肾上腺素引发血管收缩反应，该反应被肾上腺素能拮抗剂抑制。此外，去氧肾上腺素增强了内在血管运动性，并被肾上腺素能拮抗剂阻断。这些结果表明，在体外灌注下，该区域对肾上腺素能药物的反应与在体内模型中观察到的反应相似，并且还提供了兔眼动脉和/或脉络膜中肌源性自动调节特性的证据。
