Abstract
In order to shed light on the controversial issue of vagal innervation of the solar plexus ganglia, vagal efferent preganglionic fibers were anterogradely labeled by injecting the fluorescent carbocyanine dye Dil into the dorsal motor nucleus (dmnX). Additionally, Fluorogold was used to label the ganglia in toto, providing a counterstain and the possibility of UV light-guided dissection of the various ganglia. Using optical sectioning of whole mounted intact ganglia by means of laser scanning confocal microscopy, a considerable number of Dil-labeled vagal terminal-like structures were found in the major ganglia (celiac, superior mesenteric and suprarenal). Additionally, vagal efferent terminals were regularly found in microganglia associated with the periarterial plexuses of the celiac and superior mesenteric arteries, and in a few cases in small ganglia of the intermesenteric and renal plexuses. By using animals with prior selective vagal branch vagotomies, leaving only one (or a pair) of the three major abdominal divisions intact, it was concluded that the two celiac branches contribute the bulk of this vagal innervation, with the two gastric and the unpaired hepatic branch providing a small contribution mostly limited to the celiac ganglia. From control experiments, which involved Dil injections (1) into the dmnX in animals whose visceral afferents had been previously destroyed by capsaicin; (2) into the nodose ganglia, in order to anterogradely label vagal afferents; and (3) into the cervical vagus nerve as a control for uptake by fibers of passage, it was concluded that the identified terminal-like structures were vagal efferents and not inadvertently labeled afferents. We suggest that these vagal terminals have to be regarded either as ectopic parasympathetic junctions, or as part of a vagal mechanism for gating of sympathetic ganglionic transmission. Functionally, the parasympathetic innervation of the solar plexus may provide not only the classic vagal influence on gastrointestinal targets, but also vagal control of the adrenal glands and possibly other abdominal organs that have not been traditionally regarded as vagal targets.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.