Goehler L E, Sternini C
Department of Psychology, UCLA School of Medicine, USA.
Peptides. 1996;17(2):209-17. doi: 10.1016/0196-9781(95)02126-4.
The digestive system is densely innervated by calcitonin gene-related peptide (CGRP)-immunoreactive neurons. The present study investigated a) the distribution and origin of CGRP-immunoreactive fibers in the rat hepatobiliary tract, and b) their relation with substance P/tachykinin (SP/TK) immunoreactivity using immunohistochemical and radioimmunoassay techniques. CGRP-containing fibers form dense networks in the fibromuscular layer of the biliary tree and surrounding the portal vein. Thin, varicose fibers are present at the base of the mucosa of the ducts. In the liver, labeled fibers are restricted to the portal areas and the stromal compartment. Neonatal treatment with capsaicin, a neurotoxin for primary afferent neurons, or celiac/superior mesenteric ganglionectomy depletes CGRP-containing fibers in the biliary tract, and reduces those associated with the portal vein. In contrast, subdiaphragmatic vagotomy does not appreciably modify the density of these fibers. Radioimmunoassay studies show a reduction of CGRP-immunoreactive contents in the biliary tract and portal vein by 84% and 65%, respectively, following capsaicin treatment, and by 80% and 66%, respectively, following ganglionectomy. By contrast, CGRP concentrations in vagotomized animals are comparable to those of controls. Most CGRP-positive fibers appear to contain SP/TK immunoreactivity, as indicated by double-label studies. These results demonstrate that the rat hepatobiliary tract is prominently innervated by CGRP- and CGRP/SP/TK-immunoreactive fibers, which are likely to originate from spinal afferent neurons. The abundance of these fibers and their association with a variety of targets are in line with the involvement of these peptidergic visceral afferents in regulating hepatobiliary activities, including hemodynamic functions of the hepatic vasculature.
消化系统由降钙素基因相关肽（CGRP）免疫反应性神经元密集支配。本研究调查了：a）大鼠肝胆管中CGRP免疫反应性纤维的分布和起源；b）使用免疫组织化学和放射免疫测定技术，这些纤维与P物质/速激肽（SP/TK）免疫反应性的关系。含CGRP的纤维在胆管树的纤维肌层和门静脉周围形成密集网络。细的、曲张的纤维存在于导管黏膜基部。在肝脏中，标记纤维局限于门管区和间质区。用辣椒素（一种初级传入神经元的神经毒素）进行新生期处理，或进行腹腔/肠系膜上神经节切除术，可使胆管中含CGRP的纤维减少，并减少与门静脉相关的纤维。相比之下，膈下迷走神经切断术对这些纤维的密度没有明显影响。放射免疫测定研究表明，辣椒素处理后，胆管和门静脉中CGRP免疫反应性含量分别降低了84%和65%，神经节切除术后分别降低了80%和66%。相比之下，迷走神经切断术动物中的CGRP浓度与对照组相当。双重标记研究表明，大多数CGRP阳性纤维似乎含有SP/TK免疫反应性。这些结果表明，大鼠肝胆管由CGRP和CGRP/SP/TK免疫反应性纤维显著支配，这些纤维可能起源于脊髓传入神经元。这些纤维的丰富程度及其与多种靶标的关联，与这些肽能内脏传入神经参与调节肝胆活动（包括肝血管系统的血流动力学功能）是一致的。
