Characterization of PACAP receptors and signaling pathways in rabbit gastric muscle cells
Characterization of PACAP receptors and signaling pathways in rabbit gastric muscle cells
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DOI：
10.1152/ajpgi.1997.272.6.g1391
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发表时间：
1997-06-01
影响因子：
4.5
通讯作者：
Makhlouf, GM
中科院分区：
文献类型：
--
作者：
Murthy, KS;Jin, JG;Makhlouf, GM
对垂体腺苷酸环化酶激活肽（PACAP）受体及其信号通路进行了研究。与肌细胞结合的I-125-PACAP-27和i - i25血管活性肠肽（VIP）受到PACAP和VIP的抑制程度相同（平均抑制浓度为0.8 ~ 1.3 nM），暴露于任一肽的脱敏程度相同（70 ~ 80%）。PACAP与VIP一样，增加胞质游离Ca2+，形成L-[H-3]瓜氨酸、NO3-/NO2-、鸟苷3′，5′-环单磷酸（cGMP）和腺苷3′，5′-环单磷酸（cAMP），诱导松弛（平均有效浓度1.8 +/- 0.1 nM），部分被n - g -硝基-L-精氨酸（L- nna）、VIP-(10-28)和PACAP 6-38抑制。硝苯地平、L- nna和百日毒（PTx）阻断了L-[H-3]瓜氨酸和cGMP的形成，这意味着激活了G蛋白偶联的Ca2+钙调素依赖性一氧化氮（NO）合成酶。硝苯地平、L-NNA、PTx和蛋白激酶G抑制剂KT-5823对pacap诱导的松弛有相同程度的抑制作用（46-49%）；这种抑制反应反映了NO-cGMP通路介导的松弛成分。蛋白激酶A抑制剂11-89可消除残余松弛。所有反应的抑制模式与观察到的VIP相同。VIP或PACAP脱敏可以抑制cAMP的形成，但对L-[H-3]瓜氨酸和cGMP的形成没有影响。VIP或PACAP的受体保护完全保留了对任一肽的所有反应（L-[H-3]瓜氨酸、cGMP和cAMP的形成和松弛）。VIP或PACAP对受体的完全交叉竞争、交叉脱敏、交叉拮抗和交叉保护与两种肽与同一受体的相互作用一致；受体由两类组成，每一类与不同的信号通路相连。
Pituitary adenylate cyclase-activating peptide (PACAP) receptors and their signaling pathways were characterized in dispersed rabbit gastric muscle cells. I-125-PACAP-27 and I-I25-vasoactive intestinal peptide (VIP) binding to muscle cells were inhibited equally by PACAP and VIP (mean inhibitory concentration 0.8 to 1.3 nM) and desensitized to the same extent (70-80%) by exposure to either peptide. PACAP, like VIP, increased cytosolic free Ca2+ and the formation of L-[H-3]citrulline, NO3-/NO2-, guanosine 3',5'-cyclic monophosphate (cGMP), and adenosine 3',5'-cyclic monophosphate (cAMP) and induced relaxation (mean effective concentration 1.8 +/- 0.1 nM) that was partly inhibited by N-G-nitro-L-arginine (L-NNA), VIP-(10-28), and PACAP 6-38. L-[H-3]citrulline and cGMP formation were blocked by nifedipine, L-NNA, and pertussis toxin (PTx), implying activation of a G protein-coupled, Ca2+-calmodulin-dependent nitric oxide (NO) synthase. PACAP-induced relaxation was inhibited to the same extent (46-49%) by nifedipine, L-NNA, PTx, and the protein kinase G inhibitor KT-5823; the inhibition reflected the component of relaxation mediated by the NO-cGMP pathway. The residual relaxation was abolished by the protein kinase A inhibitor 11-89. The pattern of inhibition of all responses was identical to that observed with VIP. Desensitization with VIP or PACAP abolished cAMP formation but had no effect on L-[H-3]citrulline and cGMP formation induced by either peptide. Receptor protection with VIP or PACAP preserved fully all responses (L-[H-3]citrulline, cGMP, and cAMP formation and relaxation) to either peptide. The complete cross-competition, cross-desensitization, cross-antagonism, and cross-protection of receptors by either VIP or PACAP are consistent with interaction of both peptides with the same receptors; the receptors consist of two classes, each coupled to a distinct signaling pathway.