Superior Cervical Ganglion: Axonal Passage and Inputs

Feng-Bin Wang ； Pu-Ming Cheng ； Hsiao-Chun Chi ； Chih-Kuan Kao ； Yi-Han Liao

《Adaptive Medicine》 11卷1期 (2019/03) Pp. 12-17

https://doi.org/10.4247/AM.2019.ABJ226

摘要

Axons of the rostral middle (MCG) and inferior (ICG) cervical ganglion were reported to bypass the superior cervical ganglion (SCG). However, the distribution of these neurons has not been determined. Meanwhile, it has been inconsistent with the distribution of the preganglionic neurons of the SCG. To examine the above issues, we recently injected wheat germ agglutinin- horseradish peroxidase (WGA-HRP) into the entire or partial (rostral or caudal) SCG of the rat (Anatomical Record, 301:1906-1916, 2018). By preparing complete whole-mounts of the sympathetic tissues and sections of the brainstem and spinal cord, we labeled neurons that are distributed evenly in the MCG (left: 258 ＞ right: 121) ICG (left: 848, right: 681) and CST (up to 770). It is found specifically a novel cervical ganglion and termed it as the ＂pre-middle cervical ganglion＂ (pMCG) that is located rostral to the MSG and sends axons (left: 120 ＞ right: 82) to bypass the SCG. In addition to the preganglionic neurons in the cervical (C1-C4) and thoracic (T1-T4) segments, we also labeled neurons (233) that extend dendrites into the vestibular nuclear complex and locate in the intermediate reticular nuclei (96%) and perifacial zone (4%) of the brainstem ranging from Bregma -10.0 to -11.0 mm, mainly in -10.80 mm. With tracer injection into the rostral or caudal SCG, we labeled neurons correspondingly in the brainstem, C1-C2 or T1-T2. These data indicated that many neurons in pMCG, MCG and ICG run rostrally within the CST to project to their peripheral targets rather than segmentally via the closest rami. For their close anatomical location, neurons in pMCG and MCG may have similar or complementary function. Numerous neurons in the CST and caudal cervical ganglia provide bypass axons via SCG may imply special function that is useful for electroceuticals. The newly identified preganglionic neurons located in the rostral brainstem may be involved in the vestibulo-autonomic interaction for their extending dendrites into the vestibular nuclear complex that has been known to form an interaction pathway with the vagal complex.

關鍵字

Autonomic nervous system ； sympathetic nervous system ； preganglionic neurons ； postganglionic neurons ； paravertebral ganglia