Dun N J, Tang H, Dun S L, Huang R, Dun E C, Wakade A R
Department of Anatomy and Neurobiology, Medical College of Ohio, Toledo 43614, USA.
Brain Res. 1996 Apr 15;716(1-2):11-21. doi: 10.1016/0006-8993(96)00021-2.
Rat adrenal chromaffin cells were invested by a dense network of nerve fibers immunoreactive to pituitary adenylate cyclase activating polypeptide-38 (PACAP-IR). Immunohistochemical studies demonstrated the presence of PACAP-IR in nodose and dorsal root ganglion cells, but not in neurons of the intermediolateral cell column and other autonomic nuclei of the thoracic and upper lumbar spinal cord. Somata of the T7 to T12 paravertebral ganglia were PACAP-negative. A few lightly labeled neurons were occasionally noted in the dorsal motor nucleus of the vagus. Injection of the retrograde tracer Fluorogold into the left adrenal medulla 3 days prior to sacrifice resulted in the labeling of a population of neurons in the ipsilateral spinal cord intermediolateral cell column (T1 to L1), ipsilateral and contralateral nodose ganglia and ipsilateral dorsal root ganglia from T7 to T10 inclusive. A small number of lightly labeled somata was occasionally noted in the dorsal motor nucleus of the vagus. Combined retrograde tracing and PACAP immunohistochemistry showed that a population of Fluorogold-containing nodose and dorsal root ganglion cells were also PACAP-positive. Pre-treatment of the rats with capsaicin caused a marked reduction of the PACAP-IR in the adrenal gland as well as in the superficial layers of the dorsal horn and caudal spinal trigeminal nucleus. These findings, in conjunction with the apparent absence of PACAP-IR in spinal sympathetic preganglionic neurons, sympathetic postganglionic neurons, and dorsal motor nucleus of the vagus, raise the possibility that PACAP-IR fibers observed in the adrenal medulla are primarily sensory in origin. As a corollary, catecholamine secretion from chromaffin cells may be modulated by the peptidergic sensory afferents in addition to the cholinergic sympathetic preganglionic nerve fibers.
大鼠肾上腺嗜铬细胞被对垂体腺苷酸环化酶激活多肽 - 38（PACAP - IR）免疫反应阳性的密集神经纤维网络所围绕。免疫组织化学研究表明，在结状神经节和背根神经节细胞中存在PACAP - IR，但在胸段和上腰段脊髓的中间外侧细胞柱及其他自主神经核的神经元中不存在。T7至T12椎旁神经节的胞体为PACAP阴性。在迷走神经背运动核中偶尔可见少数轻度标记的神经元。在处死前3天向左侧肾上腺髓质注射逆行示踪剂荧光金，导致同侧脊髓中间外侧细胞柱（T1至L1）、同侧和对侧结状神经节以及T7至T10（含）的同侧背根神经节中的一群神经元被标记。在迷走神经背运动核中偶尔也可见少数轻度标记的胞体。联合逆行追踪和PACAP免疫组织化学显示，一群含荧光金的结状神经节和背根神经节细胞也是PACAP阳性。用辣椒素预处理大鼠会导致肾上腺以及背角浅层和尾侧三叉神经脊束核中PACAP - IR显著减少。这些发现，连同在脊髓交感神经节前神经元、交感神经节后神经元和迷走神经背运动核中明显不存在PACAP - IR，增加了在肾上腺髓质中观察到的PACAP - IR纤维主要起源于感觉神经的可能性。作为一个推论，嗜铬细胞的儿茶酚胺分泌除了受胆碱能交感神经节前神经纤维调节外，还可能受肽能感觉传入神经调节。
