Beaudet M M, Braas K M, May V
Department of Anatomy and Neurobiology, College of Medicine, University of Vermont, Burlington 05405, USA.
J Neurobiol. 1998 Sep 5;36(3):325-36.
Pituitary adenylate cyclase activating polypeptides (PACAP27 and PACAP38) are members of the VIP/secretin/glucagon family of peptides and have diverse neuroregulatory effects in sympathoadrenal cell development and function. PACAP peptides regulate rat superior cervical ganglion (SCG) neuron catecholamine and neuropeptide Y content and secretion, and promote sympathoneuroblast survival through activation of specific PACAP1 receptor isoforms. In examining the potential sources of PACAP regulating the SCG, PACAP expression was identified in rat preganglionic neurons in the intermediolateral cell column (IML) of the thoracic spinal cord which provide primary afferent projections to this sympathetic ganglion. Thoracic spinal cord segments (T1-4) contained approximately 17 pmol PACAP38 immunoreactivity/g tissue wet weight. Reverse-transcription polymerase chain reaction of cDNA from microdissected thoracic spinal cord using primers specific for rat neuronal proPACAP identified proPACAP mRNA expression in the IML; the results correlated with neurons labeled for proPACAP mRNA by in situ hybridization histochemistry and implicated PACAP biosynthesis in IML neurons. To demonstrate directly proPACAP transcript expression in preganglionic projection neurons to the SCG, the ganglion was decentralized and the sympathetic trunk immersed in fluorogold to identify sympathetic preganglionic neurons by retrograde labeling. Cryosections of spinal cord segments containing preganglionic neuron fluorogold labeled neurons were processed subsequently for in situ hybridization histochemical localization of proPACAP mRNA using a digoxigenin-labeled riboprobe; IML neurons were examined for fluorogold and digoxigenin/alkaline phosphatase product dual labeling. More than half of the preganglionic projection neurons to the SCG expressed PACAP mRNA, consistent with the postulate that PACAP peptides released from a subpopulation of thoracic IML preganglionic neurons may be physiological anterograde modulators of sympathetic SCG function.
垂体腺苷酸环化酶激活多肽（PACAP27和PACAP38）是VIP/促胰液素/胰高血糖素肽家族的成员，在交感肾上腺细胞的发育和功能中具有多种神经调节作用。PACAP肽调节大鼠颈上神经节（SCG）神经元的儿茶酚胺和神经肽Y含量及分泌，并通过激活特定的PACAP1受体亚型促进交感神经母细胞存活。在研究调节SCG的PACAP的潜在来源时，在大鼠胸段脊髓中间外侧细胞柱（IML）的节前神经元中发现了PACAP表达，这些神经元向该交感神经节提供初级传入投射。胸段脊髓节段（T1 - 4）含有约17 pmol PACAP38免疫反应性/克组织湿重。使用针对大鼠神经元proPACAP的特异性引物对显微切割的胸段脊髓cDNA进行逆转录聚合酶链反应，确定IML中proPACAP mRNA的表达；结果与原位杂交组织化学标记proPACAP mRNA的神经元相关，并提示IML神经元中存在PACAP生物合成。为了直接证明向SCG的节前投射神经元中proPACAP转录本的表达，将神经节分散，将交感干浸入荧光金中，通过逆行标记来识别交感节前神经元。随后，使用地高辛标记的核糖探针，对含有节前神经元荧光金标记神经元的脊髓节段冰冻切片进行proPACAP mRNA的原位杂交组织化学定位；检查IML神经元的荧光金和地高辛/碱性磷酸酶产物双重标记。超过一半的向SCG的节前投射神经元表达PACAP mRNA，这与以下假设一致，即从胸段IML节前神经元亚群释放的PACAP肽可能是交感SCG功能的生理性顺行调节剂。
