Distribution And Origin Of Adrenergic Nerve Fibers In The Vestibular Apparatus And Their Arterial Supply In The Guinea Pig: A Fluorescent Microscopic Study

Abstract

Fine adrenergic nerve fibers which are distributed to the saccular and utricular maculae, ampullar capsules and ducts of the semicircular canals and vestibular nerve of the guinea pig were observed by fluorescent microscopy. These fibers were divided into three groups according to their course and location: perivascular, nerve trunk, and independent groups. The arteries leading to the vestibular organs contained many adrenergic fibers. The uni- and bilateral cervical sympathetic denervations at various levels showed that the adrenergic fibers in the vestibular organs originated in the ipsilateral superior cervical ganglion. Regarding the arteries leading to the vestibular organs, the basilar, anterior inferior cere-bellar, labyrinthine and common cochlear arteries receive adrenergic fibers from the bilateral superior cervical ganglia, while the peripheral branches of the labyrinthine artery receive their adrenergic fibers only from the ipsilateral superior cervical ganglion. These adrenergic fibers come from the ganglion via the internal carotid nerve.