Expression and regulation of calcitonin gene-related peptide receptor in rat placentas
Expression and regulation of calcitonin gene-related peptide receptor in rat placentas
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DOI：
10.1093/biolreprod/67.4.1321
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发表时间：
2002-10-01
影响因子：
3.6
通讯作者：
Yallampalli, C
中科院分区：
文献类型：
--
作者：
Dong, YL;Vegiraju, S;Yallampalli, C
降钙素基因相关肽（CGRP）是目前已知最强的血管扩张剂之一，通过与受体相互作用发挥其生物学作用。最近的报道表明存在两种类型的CGRP受体，CGRP-A和CGRP-B。目前的研究旨在检查大鼠胎盘中是否存在CGRP-B受体，如果存在，它们是否受胎龄和性类固醇激素的调节。胎盘从定时妊娠的Sprague-Dawley大鼠获得，所述大鼠在分娩前和分娩期间的第17-21天和第22天处死（每个胎龄n = 6）。此外，还从注射孕酮（P，4 mg/大鼠/天s.c.第20-22天）、抗孕酮RU 486（10 mg/大鼠s.c.第17天）、17 β-雌二醇（5 μ g/大鼠s.c.第17天）和抗雌激素ICI 182780（0.3 μ g/大鼠s.c.第17天）。结果显示，首先，使用单克隆抗CGRP-B受体抗体对大鼠胎盘进行免疫荧光染色，揭示了CGRP-B受体存在于胎盘的绒毛膜层，特别是滋养层和血管内皮细胞以及下面的平滑肌细胞。在分娩过程中获得的胎盘中染色强度较低。第二，在大鼠胎盘的Western印迹中获得了一条66 kDa的单一条带，与CGRP-B受体抗体反应;第三，蛋白条带的光密度分析显示，CGRP-B受体从第17天到第22天增加，在临产前第22天达到最高水平，是第17天的10倍第四，大鼠胎盘组织中CGRP-B受体的表达在分娩过程中减少第五，在分娩前第20-22天给予P减轻了足月分娩时胎盘CGRP-B受体的下降;第六，在妊娠第17天给予RU-486显著降低胎盘CGRP-B受体的表达（6 h为18%，对照组为100%，P < 0.01）：第七，雌激素治疗后48 h，CGRP-B受体表达明显下降;第八，ICI 182780处理第17天增加胎盘CGRP-13受体（48 h时152% vs.100%，P < 0.01）。这些结果表明，CGRP-B受体存在于大鼠胎盘，受体水平随胎龄增加而升高，足月分娩时降低。孕激素刺激和雌激素抑制胎盘CGRP-B受体表达。因此，妊娠晚期胎盘CGRP-B受体的升高可能在增加与妊娠晚期胎儿快速生长相关的胎儿胎盘单位的血流量中发挥作用。
Calcitonin gene-related peptide (CGRP), one of the most potent vasodilators known, exerts its biological action by interacting with its receptors. Recent reports suggest the existence of two types of CGRP receptors, CGRP-A and CGRP-B. The current study was designed to examine whether CGRP-B receptors are present in the rat placenta, and if they are, whether they are modulated by gestational age and by sex-steroid hormones. Placentas were obtained from timed pregnant Sprague-Dawley rats that were killed on Days 17-21 and 22 before and during labor (n = 6 for each gestational age). In addition, placentas were also obtained from pregnant rats injected with progesterone (P,; 4 mg per rat per day s.c. on Days 20-22), antiprogesterone RU486 (10 mg/rat s.c. on Day 17), 17beta-estradiol (5 mug/rat s.c. on Day 17), and antiestrogen ICI 182780 (0.3 mug/rat s.c. on Day 17). Results showed that first, immunoflourescent staining of rat placentas using monoclonal anti-CGRP-B receptor antibody revealed the presence of CGRP-B receptors in the labyrinthine layer of the placenta, specifically to the trophoblast and blood vessel endothelium and underlying smooth muscle cells. The intensity of staining was lower in placentas obtained during labor. Second, a single band of 66 kDa, reactive to CGRP-B receptor antibody, was obtained in Western blotting of the rat placenta; third, densitometric analysis of protein bands showed that CGRP-B receptors were increased from Day 17 to Day 22, with maximal levels obtained on Day 22 before labor, which was 10 times higher than that of Day 17 (P < 0.01); fourth, expression of CGRP-B receptors in rat placenta decreased during labor (8% vs. 100% on Day 22 before labor, P < 0.01); fifth, P, given during Days 20-22 attenuated the fall in placental CGRP-B receptors at term labor; sixth, RU-486 given on Day 17 of gestation significantly decreased expression of placental CGRP-B receptors (18% vs. 100% in controls at 6 h, P < 0.01); seventh, a significant decrease in CGRP-B receptor expression was noted 48 h after estrogen administration; and eighth, ICI 182780 treatment on Day 17 increased placental CGRP-13 receptors (152% vs. 100% in control at 48 h, P < 0.01). These results indicate that CGRP-B receptors are present in rat placenta and that receptor levels are higher with gestational age and lower at term labor. Progesterone stimulated and estrogen inhibited placental CGRP-B receptor expression. Thus, elevations in placental CGRP-B receptors in late pregnancy could play a role in increasing blood flow through the fetoplacental unit associated with rapid fetal growth during late gestation.