V(2)-LIKE VASOPRESSIN RECEPTOR MOBILIZES INTRACELLULAR CA2+ IN RAT MEDULLARY COLLECTING TUBULES
V(2)-LIKE VASOPRESSIN RECEPTOR MOBILIZES INTRACELLULAR CA2+ IN RAT MEDULLARY COLLECTING TUBULES
复制标题
DOI：
10.1152/ajprenal.1993.265.1.f35
复制
发表时间：
1993-07-01
影响因子：
--
通讯作者：
IMBERTTEBOUL, M
中科院分区：
文献类型：
--
作者：
CHAMPIGNEULLE, A;SIGA, E;IMBERTTEBOUL, M
在单个显微解剖的大鼠髓质集合管 [外 (OMCD) 和内 (IMCD)] 中测量胞质游离钙浓度 ([Ca2+]i)，以识别参与加压素 (AVP) 诱导的 [Ca2+]i 增加的受体。在这两个片段中，[Phe2,Orn8]加压素 ([Phe2,Orn8]VT)（一种特定的 V1 激动剂）以及 V2 激动剂 1-desamino-8-D-AVP (dDAVP) 都会触发 [Ca2+]i 变异。在 OMCD 中，对 10 nM AVP 的平均反应大致相当于 V1 和 V2 激动剂效应的总和。在 IMCD 中，单独使用 dDAVP (10 nM) 即可重现对 AVP 的钙反应（分别使用 dDAVP 和 AVP 时，DELTA[Ca2+]i = 243 +/- 34 nM，n = 6，以及 248 +/- 27 nM，n = 8）。此外，在相同的实验中，V1 和 V2 最大效应不是相加的（[Phe2 Orn8]VT = 154 +/- 21 nM，n = 6；dDAVP + [Phe2 Orn8]VT = 233 +/- 23 nM，n = 9）。作为 AVP，dDAVP 释放细胞内钙（无钙培养基中的 DELTA[Ca2+]i = 182 +/- 24 nM，n = 8，而 dDAVP 和 AVP 分别为 182 +/- 14 nM，n = 6）。 8-(4-氯苯硫基)腺苷 3',5'-环单磷酸和毛喉素均未修饰 [Ca2+]i。可以排除 dDAVP 与催产素 (OT) 受体的交叉反应，因为 1) 特定 OT 激动剂 [Thr4,Gly7] OT (10 nM) 仅轻微增加 [Ca2+]i (DELTA-[Ca2+]i = 20 +/- 5 nM, n = 11) 2) 特定 OT 拮抗剂不会改变 dDAVP 反应[1-(O-巯基-O,O-环五亚甲基丙酸)、2-(O-甲基)酪氨酸、4-苏氨酸、8-鸟氨酸、9-酪氨酰胺]加压素[d(CH2)51,O-Me-Tyr2, Thr4, Tyr-NH29] OVT； 3) 它对 V1 拮抗剂不敏感，但被 V1/V2 拮抗剂 [d(CH2)5,O-Et-Tyr2,Val4]AVP 完全阻断 ([DELTA[Ca2+]i = 18 +/- 4 nM, n = 6)。这些结果表明，在 IMCD 中，AVP 通过 V1 和 V2 受体增加 [Ca2+]i。 [Ca2+]i，V2 受体引起的变异涉及独立于腺苷酸环化酶并与 V1 和 V2 受体相同的细胞内钙池偶联的机制。
Cytosolic free calcium concentration ([Ca2+]i) was measured in single microdissected rat medullary collecting tubules [outer (OMCD) and inner (IMCD)] to identify receptors involved in vasopressin (AVP)-induced [Ca2+]i increases. In both segments, [Phe2, Orn8]vasotocin ([Phe2,Orn8]VT), a specific V1 agonist, as well as the V2 agonist 1-desamino-8-D-AVP (dDAVP) triggered [Ca2+]i variations. In OMCD, the mean response to 10 nM AVP roughly corresponded to the sum of V1 and V2 agonists effects. In IMCD, dDAVP (10 nM) alone reproduced the calcium response to AVP (DELTA[Ca2+]i = 243 +/- 34 nM, n = 6, and 248 +/- 27 nM, n = 8, with dDAVP and AVP, respectively). Furthermore, in the same experiments V1 and V2 maximal effects were not additive ([Phe2 Orn8]VT = 154 +/- 21 nM, n = 6; dDAVP + [Phe2 Orn8]VT = 233 +/- 23 nM, n = 9). As AVP, dDAVP released intracellular calcium (DELTA[Ca2+]i in calcium-free medium = 182 +/- 24 nM, n = 8, vs. 182 +/- 14 nM, n = 6 with 10 nM dDAVP and AVP, respectively). Neither 8-(4-chlorophenylthio)adenosine 3',5'-cyclic monophosphate nor forskolin modified [ Ca2+]i. A cross-reaction of dDAVP with an oxytocin (OT) receptor can be excluded since 1) the specific OT agonist [Thr4,Gly7] OT (10 nM) increased only slightly [Ca2+]i (DELTA-[Ca2+]i = 20 +/- 5 nM, n = 11) 2) the dDAVP response was not altered by the specific OT antagonist [1-(O-mercapto-O,O-cyclopentamethylene propionic acid), 2-(O-methyl)tyrosine,4-threonine, 8-ornithine,9-tyrosylamide]vasotocin [d(CH2)51,O-Me-Tyr2, Thr4, Tyr-NH29] OVT; 3) it was insensitive to V1 antagonists but was totally blocked by the V1/V2 antagonist [d(CH2)5,O-Et-Tyr2,Val4]AVP ([DELTA[Ca2+]i = 18 +/- 4 nM, n = 6). These results indicate that in IMCD AVP increases [Ca2+]i via both V1 and V2 receptors. [Ca2+]i, variations due to V2 receptors involve a mechanism independent of adenylate cyclase and coupled to the same intracellular calcium pool as V1 and V2 receptors.