Lee B H, Lynn R B, Lee H S, Miselis R R, Altschuler S M
Division of Gastroenterology and Nutrition, Children's Hospital of Philadelphia, Pennsylvania 19104.
J Comp Neurol. 1992 Jun 22;320(4):531-43. doi: 10.1002/cne.903200410.
Calcitonin gene-related peptide has been reported in the rat nucleus ambiguus. This nucleus comprises a dorsal division that is the source of special visceral efferents innervating the striated muscle of the upper alimentary tract and a ventral division supplying general visceral efferents primarily to the heart. The distribution of calcitonin gene-related peptide immunoreactive neurons in the two divisions was determined by using a combination of immunocytochemical techniques and fluorescent retrograde tracing. In 22 rats, injections of Fluoro-Gold were made into either the supranodosal vagus nerve, palatopharynx, larynx, esophagus, or heart. Following colchicine injection, medullary sections were processed immunocytochemically for calcitonin gene-related peptide. Injection of Fluoro-Gold into the supranodosal vagus resulted in prominent labeling of neurons in the dorsal and ventral divisions of the nucleus ambiguus. The majority of fluorescent labeled neurons in the dorsal division were found to be immunoreactive for calcitonin gene-related peptide, while those labeled neurons in the ventral division were unreactive for the peptide. With esophageal, and palatopharyngeal and cricothyroid injections, many fluorescent labeled neurons that were immunoreactive for calcitonin gene-related peptide were found respectively in the compact and semicompact formations of the dorsal division. In contrast, injections of the heart resulted in fluorescent labeled neurons, which were unreactive for calcitonin gene-related peptide, localized to the external formation. The results demonstrate that calcitonin gene-related peptide immunoreactive neurons are localized entirely to the dorsal division of the nucleus ambiguus and that all striated muscular areas of the alimentary tract are innervated by calcitonin gene-related peptide containing motoneurons. The localization of calcitonin gene-related peptide to vagal motoneurons also known to contain acetylcholine and the increase in acetylcholine receptor synthesis caused by this peptide suggest that calcitonin gene-related peptide acts as a cotransmitter with acetylcholine in special visceral efferent vagal motoneurons.
降钙素基因相关肽已在大鼠疑核中被报道。该核由一个背侧部和一个腹侧部组成，背侧部是支配上消化道横纹肌的特殊内脏传出纤维的来源，腹侧部主要向心脏提供一般内脏传出纤维。通过免疫细胞化学技术和荧光逆行追踪相结合的方法，确定了降钙素基因相关肽免疫反应性神经元在这两个部分的分布。在22只大鼠中，将荧光金注射到结状上迷走神经、腭咽、喉、食管或心脏。注射秋水仙碱后，对延髓切片进行降钙素基因相关肽的免疫细胞化学处理。将荧光金注射到结状上迷走神经，导致疑核背侧部和腹侧部的神经元有明显标记。发现背侧部大多数荧光标记神经元对降钙素基因相关肽有免疫反应，而腹侧部那些标记神经元对该肽无反应。通过食管、腭咽和环甲肌注射，分别在背侧部的致密和半致密结构中发现许多对降钙素基因相关肽有免疫反应的荧光标记神经元。相反，心脏注射导致荧光标记神经元定位于外侧结构，这些神经元对降钙素基因相关肽无反应。结果表明，降钙素基因相关肽免疫反应性神经元完全定位于疑核的背侧部，并且消化道的所有横纹肌区域均由含降钙素基因相关肽的运动神经元支配。降钙素基因相关肽定位于已知也含有乙酰胆碱的迷走运动神经元，以及该肽引起的乙酰胆碱受体合成增加，提示降钙素基因相关肽在特殊内脏传出迷走运动神经元中作为乙酰胆碱的共递质发挥作用。
