Role of endothelin-1 in choroidal blood flow regulation during isometric exercise in healthy humans
Role of endothelin-1 in choroidal blood flow regulation during isometric exercise in healthy humans
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DOI：
10.1167/iovs.02-0372
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发表时间：
2003-02-01
影响因子：
4.4
通讯作者：
Schmetterer, L
中科院分区：
文献类型：
--
作者：
Fuchsjäger-Mayrl, G;Luksch, A;Schmetterer, L
目的。有证据表明，脉络膜对眼球灌注压(OPP)的变化有一定的自我调节能力。到目前为止，这一反应的调解人还没有确定。本研究假设内皮素(EI)-1和/或血管紧张素-II(ANF)-II托盘参与脉络膜血管收缩。方法对12名健康男性志愿者进行随机、双盲、安慰剂对照、三方交叉研究。受试者在不同的研究日期接受特定的ET受体拮抗剂BQ-123、血管紧张素转换酶抑制剂依那普利或安慰剂的静脉输注。在这些输液期间，受试者被要求蹲下几分钟。使用激光共聚焦多普勒血流仪测量脉络膜血流量，并根据平均动脉压和锁骨内压计算眼暂留压(OPP)。结果：BQ423和依那普利对基础血压、脉搏、眼内压和脉络膜血流量没有影响。在等长运动中，观察到平均动脉压的显著增加与OPP VAS的增加相平行。虽然蹲着时脉络膜血流量略有增加，但这种增加远没有DPP的增加明显，这表明脉络膜有一定的调节潜力。依那普利不改变等长运动时脉络膜压力-流量关系，但BQ-123使脉络膜压力-流量曲线显著左移(P<；0.001)。结论：目前的数据表明，在健康人体等长运动中，ET-1而不是Ang B在脉络膜血流调节中起作用。因此，眼血管疾病患者托盘中脉络膜自动调节功能受损的原因是内皮系统的改变。有必要对这类患者进行进一步研究，以验证DAIS假说。
PURPOSE. There is evidence that the choroid has some autoregulatory capacity in response to changes in ocular perfusion pressure (OPP). The mediators of this response are hitherto unidentified. The hypothesis for the current study was that endothelin (EI)-1 and/or angiotensin (ANF)-II tray be involved in choroidal vasoconstriction during an increase in OPP.METHODS. To test this hypothesis a randomized, double-masked, placebo controlled, three way crossover study was performed in 12 healthy male volunteers. Subjects received on different study days intravenous infusions of the specific ET,, receptor antagonist BQ-123, the angiotensin converting enzyme inhibitor enalapril or placebo. During these infusion periods subjects were asked to squat for minutes. Choroidal blood flow was measured using a confocal laser Doppler flowmeter and ocular pension pressure (OPP) was calculated from mean arterial pressure and intraoclar pressure.RESULTS. BQ423 and enalapril had no effect on basal blood pressure, pulse rate, intraocular pressure, or choroidal blood flow. During isometric exercise, a pronounced increase in mean arterial pressure paralleled by an increase in OPP Vas observed. Although choroidal blood flow slightly increased during squatting, the increase was much less pronounced than the increase in DPP, indicating some regulatory potential of the choroid. Enalapril did not alter the choroidal pressure-flow relationship during; isometric exercise, but BQ-123 induced a significant leftward shift of the pressure-flow cure (P < 0.001).CONCLUSIONS. The present data indicate that ET-1, but not ANG B, plays a role in choroidal blood flow regulation during isometric exercise in healthy humans. Hence, impaired choroidal autoregulation in patients with ocular vascular diseases tray arise from an altered endothelia system. Further studies in such patients are warranted to verify dais hypothesis.