Basille M, Gonzalez B J, Desrues L, Demas M, Fournier A, Vaudry H
European Institute for Peptide Research (IFRMP 23), UA CNRS, University of Rouen, Mont-Saint-Aignan, France.
J Neurochem. 1995 Sep;65(3):1318-24. doi: 10.1046/j.1471-4159.1995.65031318.x.
The presence of receptors for the novel neuropeptide pituitary adenylate cyclase-activating polypeptide (PACAP) has been recently demonstrated in the external granule cell layer of the cerebellum, a germinative matrix that generates the majority of cerebellar interneurons. In the present study, we have taken advantage of the possibility of obtaining a culture preparation that is greatly enriched in immature cerebellar granule cells to investigate the effect of PACAP on the adenylyl cyclase and phospholipase C transduction pathways. The two molecular forms of PACAP, i.e., 27-(PACAP27) and 38-(PACAP38) amino-acid forms of PACAP, induced a dose-dependent stimulation of cyclic AMP production in granule cells. The potencies of PACAP27 and PACAP38 were similar (ED50 = 0.12 +/- 0.01 and 0.23 +/- 0.07 nM, respectively), whereas vasoactive intestinal polypeptide (VIP) was approximately 100 times less potent. PACAP27 and PACAP38 also induced a dose-dependent stimulation of polyphosphoinositide breakdown (ED50 = 19.1 +/- 6.3 and 13.4 +/- 6.0 nM, respectively), whereas VIP had no effect on polyphosphoinositide metabolism. The effect of PACAP38 on inositol phosphate formation was significantly reduced by U-73122 and by pertussis toxin, indicating that activation of PACAP receptors causes stimulation of a phospholipase C through a pertussis toxin-sensitive G protein. In contrast, forskolin and dibutyryl cyclic AMP did not affect PACAP-induced stimulation of inositol phosphates. Taken together, the present results demonstrate that PACAP stimulates independently the adenylyl cyclase and the phospholipase C transduction pathways in immature cerebellar granule cells. These data favor the concept that PACAP may play important roles in the control of proliferation and/or differentiation of cerebellar neuroblasts.
最近已证实在小脑的外颗粒细胞层（即产生大多数小脑中间神经元的生发基质）中存在新型神经肽垂体腺苷酸环化酶激活多肽（PACAP）的受体。在本研究中，我们利用获得富含未成熟小脑颗粒细胞的培养制剂的可能性，来研究PACAP对腺苷酸环化酶和磷脂酶C转导途径的影响。PACAP的两种分子形式，即27个氨基酸的PACAP27和38个氨基酸的PACAP38，在颗粒细胞中诱导了环磷酸腺苷（cAMP）生成的剂量依赖性刺激。PACAP27和PACAP38的效力相似（ED50分别为0.12±0.01和0.23±0.07 nM），而血管活性肠肽（VIP）的效力约低100倍。PACAP27和PACAP38还诱导了多磷酸肌醇分解的剂量依赖性刺激（ED50分别为19.1±6.3和13.4±6.0 nM），而VIP对多磷酸肌醇代谢没有影响。U-73122和百日咳毒素显著降低了PACAP38对肌醇磷酸形成的影响，表明PACAP受体的激活通过对百日咳毒素敏感的G蛋白导致磷脂酶C的刺激。相反，福司可林和二丁酰环磷酸腺苷不影响PACAP诱导的肌醇磷酸刺激。综上所述，目前的结果表明，PACAP在未成熟小脑颗粒细胞中独立刺激腺苷酸环化酶和磷脂酶C转导途径。这些数据支持了PACAP可能在小脑神经母细胞的增殖和/或分化控制中起重要作用的观点。
