Abstract
Presence of many autonomic small ganglia in oro-facial regions has been reported in mammals. However, localizations of the ganglia and their morphological properties have not been known in detail. In the present study we investigate whole localizations of cranial autonomic ganglia, pathways of their postganglionic fibers, their characteristic histological properties and their postulated functions. A microdissection using a whole-mount acetylcholinesterase histochemistry revealed whole localizations of ganglia clearly, and a histological analysis indicated that the ganglia were parasympathetic in nature. Two kinds of neurons, a large and a small one, were readily discernible in silver-gold staining preparations. Many ganglia contained both types of neurons, while, considerable number of microganglia consisted of only the small neurons. In injections of tracers into glandular regions, both small and large neurons were retrogradely labeled. While, injections into gland-free regions resulted in labeling in the small neurons exclusively, and the labeled neurons were found in two or more microganglia. In nicotinamide adenine dinucleotide phosphate (NADPH)-diaphorase stained preparations, almost all small neurons were intensely labeled. These findings suggest that blood vessels in the cranio-oro-facial regions were innervated by the small nitrergic neurons and the neurons may regulate local circulation grossly. [Jpn J Physiol 54 Suppl:S12 (2004)]
