Schalk K A, Faraci F M, Heistad D D
Department of Internal Medicine, University of Iowa College of Medicine, Iowa City 52242.
Stroke. 1992 Apr;23(4):560-3. doi: 10.1161/01.str.23.4.560.
Endothelin is a potent vasoconstrictor in several tissues, including the choroid plexus. The goal of this study was to determine whether endothelin affects the production of cerebrospinal fluid.
Ventriculocisternal perfusion was used to measure the production of cerebrospinal fluid in anesthetized rabbits. Changes in production of cerebrospinal fluid were examined in response to vehicle, intravenous endothelin (alone and in the presence of indomethacin), and intraventricular endothelin.
Under control conditions, the reduction in production of cerebrospinal fluid in response to endothelin administered intravenously was only modestly greater than that during infusion of vehicle. Because endothelin releases cyclooxygenase products that attenuate the direct effects of endothelin in several tissues, effects of endothelin on the production of cerebrospinal fluid were also examined after inhibition of cyclooxygenase. Production of cerebrospinal fluid in response to 1 micrograms/kg i.v. endothelin was reduced more in animals treated with indomethacin than in untreated animals (-34 +/- 7% [mean +/- SEM] versus -14 +/- 6%, p less than 0.05). Thus, effects of endothelin on the production of cerebrospinal fluid are attenuated by cyclooxygenase products. Finally, responses to intraventricular endothelin were examined. Intraventricular endothelin produced a modest, but significant, reduction in the production of cerebrospinal fluid.
In summary, endothelin may play a role in regulation of the brain fluid balance by affecting the rate of production of cerebrospinal fluid, and this effect is modulated by cyclooxygenase products.
内皮素在包括脉络丛在内的多种组织中是一种强力血管收缩剂。本研究的目的是确定内皮素是否影响脑脊液的生成。
采用脑室池灌注法测量麻醉兔脑脊液的生成。检测了给予赋形剂、静脉注射内皮素（单独及与吲哚美辛同时使用）和脑室内注射内皮素后脑脊液生成的变化。
在对照条件下，静脉注射内皮素后脑脊液生成的减少仅略大于输注赋形剂期间。由于内皮素释放的环氧化酶产物会减弱内皮素在多种组织中的直接作用，因此在抑制环氧化酶后也研究了内皮素对脑脊液生成的影响。与未治疗动物相比，吲哚美辛治疗的动物对1微克/千克静脉注射内皮素的脑脊液生成减少更多（-34±7%[平均值±标准误]对-14±6%，p<0.05）。因此，环氧化酶产物减弱了内皮素对脑脊液生成的作用。最后，检测了对脑室内注射内皮素的反应。脑室内注射内皮素使脑脊液生成有适度但显著的减少。
总之，内皮素可能通过影响脑脊液生成速率在脑液平衡调节中起作用，且这种作用受环氧化酶产物调节。
