CALCITONIN GENE-RELATED PEPTIDE - EFFECTS ON RENAL ARTERIOLAR TONE AND TUBULAR CAMP LEVELS
CALCITONIN GENE-RELATED PEPTIDE - EFFECTS ON RENAL ARTERIOLAR TONE AND TUBULAR CAMP LEVELS
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DOI：
10.1152/ajprenal.1990.258.1.f121
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发表时间：
1990-01-01
影响因子：
--
通讯作者：
TRIZNA, W
中科院分区：
文献类型：
--
作者：
EDWARDS, RM;TRIZNA, W
比较了降钙素基因相关肽（CGRP）和鲑鱼降钙素（SCTA）对兔肾离体小管传入、出动脉张力和腺苷3′，5′-环单磷酸腺苷（cAMP）积累的影响。CGRP和SCT本身对小动脉直径没有影响。在去甲肾上腺素收缩的传入小动脉中，CGRP而非SCT产生浓度依赖性松弛[50%最大剂量，(EC50) = 1.3 nM]。相比之下，CGRP和SCT对去甲肾上腺素或血管紧张素II预收缩的输出小动脉没有任何影响。CGRP刺激cAMP在肾小球中的积累（EC50 = 0.5 nM），而SCT没有。在小管中，CGRP仅在sct反应节段增加cAMP水平，例如皮质和髓质厚升肢和远曲小管。在髓质厚升肢，CGRP约为。ec50为0.22亩，刺激cAMP积累的效力比SCT低500倍。M和0.41 nM。最大浓度(1。M) CGRP和SCT对髓质厚升肢cAMP水平的影响无加性。结果表明，在传入小动脉上和肾小球中存在特定的CGRP受体，这些受体产生舒张，与cAMP产生的增加有关。在小管中，CGRP似乎是SCT受体的弱激动剂。综上所述，CGRP可能参与肾脏血流动力学的调节。
The effects of calcitonin gene-related peptide (CGRP) and salmon clacitonin (SCTA) on isolated afferent and efferent arteriolar tone and on adenosine 3'',5''-cyclic monophosphate(cAMP) accumulation in isolated tubules from rabbit kidney were compared. By themselves, CGRP and SCT had no effect on arteriole diameter. In norepinephrine-contracted afferent arterioles, CGRP, but not SCT, produced a concentration-dependent relaxation [50% maximal dose, (EC50) = 1.3 nM]. In contrast, neither CGRP nor SCT had any effect on efferent arterioles precontracted with norepinephrine or angiotensin II. CGRP, but not SCT, stimulated cAMP accumulation in glomeruli (EC50 = 0.5 nM). In tubules, CGRP increased cAMP levels only in SCT-responsive segments, e.g., cortical and medullary thick ascending limbs and distal convoluted tubules. In the medullary thick ascending limb, CGRP was .apprx.500-fold less potent than SCT in stimulating cAMP accumulation with EC50s of 0.22.mu.M and 0.41 nM, respectively. The effect of maximum concentrations (1 .mu.M) of CGRP and SCT on cAMP levels in the medullary thick ascending limb were not additive. The results suggest that there are specific CGRP receptors on afferent arterioles that produce relaxation and in glomeruli that are associated with an increase in cAMP production. In tubules, CGRP appears to be a weak agonist at the SCT receptor. We conclude that CGRP may play a role in the regulation of renal hemodynamics.