Nitric oxide modulates angiotensin II-induced drinking behavior in the near-term ovine fetus
Nitric oxide modulates angiotensin II-induced drinking behavior in the near-term ovine fetus
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DOI：
10.1067/mob.2000.104227
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发表时间：
2000-03-01
影响因子：
9.8
通讯作者：
Ross, MG
中科院分区：
文献类型：
--
作者：
El-Haddad, MA;Chao, CR;Ross, MG
目的：人类和绵羊胎儿表现出自发吞咽和血管紧张素II刺激吞咽的增加率。血管紧张素II和一氧化氮合酶已经定位于大脑中的口渴中心。本研究进行，以确定中央一氧化氮是否有助于调节血管紧张素II诱导的胎儿swallowing.Study设计：6怀孕母羊与近期单胎长期准备胎儿血管和侧脑室导管和electrocorticograms和食管肌电图电极。在2小时的对照期后，向胎仔连续侧脑室注射（1 mL）血管紧张素II（3.2 μ g;时间，2小时）和N ω-硝基-L-精氨酸甲酯（3 mg;时间，3小时），并重复注射血管紧张素II（3.2 μ g;时间，5小时）。所有胎儿在前一天接受侧脑室注射人工脑脊液的额外对照研究。结果：血管紧张素II注射显著增加平均+/- SEM胎儿吞咽（0.9 +/- 0.1至2.7 +/- 0.4吞咽/min）。N ω-硝基-L-精氨酸甲酯显着降低胎儿吞咽到低于基础率（0.4 +/- 0.1吞咽/分钟），吞咽并没有增加与第二次血管紧张素II剂量（在存在一氧化氮阻断）。结论：这些结果表明，抑制中枢一氧化氮抑制胎儿吞咽行为，响应于中央血管紧张素II。我们推测，紧张性一氧化氮通过维持谷氨酸激活下丘脑N-甲基-D-天冬氨酸受体促进血管紧张素II吞咽刺激。
OBJECTIVE: Human and ovine fetuses demonstrate an enhanced rate of spontaneous and angiotensin II-stimulated swallowing. Angiotensin II and nitric oxide synthase have been localized to thirst centers in the brain. This study was performed to determine whether central nitric oxide contributes to the regulation of angiotensin II-induced fetal swallowing.STUDY DESIGN: Six pregnant ewes with near-term singleton fetuses were chronically prepared with fetal vascular and lateral ventricle catheters and electrocorticogram and esophageal electromyogram electrodes. After a 2-hour control period, fetuses were administered serial lateral ventricle injections (1 mL) of angiotensin II (3.2 mu g; time, 2 hours) and N omega-nitro-L-arginine methyl ester (3 mg; time, 3 hours) and a repeat angiotensin II injection (3.2 mu g; time, 5 hours). All fetuses received an additional control study of lateral ventricle injections of artificial cerebrospinal fluid on a previous day.RESULTS: Angiotensin II injection significantly increased mean +/- SEM fetal swallowing (0.9 +/- 0.1 to 2.7 +/- 0.4 swallows/min). N omega-nitro-L-arginine methyl ester significantly decreased fetal swallowing to below the basal rate (0.4 +/- 0.1 swallows/min), and swallowing did not increase with the second angiotensin II dose (in the presence of nitric oxide blockade).CONCLUSIONS: These results demonstrate that inhibition of central nitric oxide suppresses fetal swallowing behavior in response to central angiotensin II. We speculate that tonic nitric oxide facilitates angiotensin II swallowing stimulation by maintenance of glutamate activation of hypothalamic N-methyl-D-aspartate receptors.