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March 1992

Innervation of the Endolymphatic Sac

Author Affiliations

From the Division of Otolaryngology—Head and Neck Surgery, Department of Surgery, University of North Carolina School of Medicine, Chapel Hill (Drs Brechtelsbauer, Prazma, and Pillsbury, and Mr Baxter); and Hunan Medical University, Changsha, China (Dr Xie).

Arch Otolaryngol Head Neck Surg. 1992;118(3):260-264. doi:10.1001/archotol.1992.01880030042010

• Previous studies suggest that the endolymphatic sac plays an important role in the homeostasis of endolymph. Factors that influence blood flow in the sac may affect its function. This blood flow may be influenced by autonomic innervation; however, no such innervation has been demonstrated. The purpose of this study was to demonstrate catecholaminergic and cholinergic fibers on the endolymphatic sac. Endolymphatic sacs from Hartley guinea pigs were stained either immunocytochemically for tyrosine hydroxylase to reveal catecholaminergic fibers or histochemically for acetylcholinesterase to reveal cholinergic fibers. For tyrosine hydroxylase immunostaining, the endolymphatic sacs were treated with dilute hydrogen peroxide and then incubated in the primary antiserum. The tissue was further processed by the avidin-biotin immunoperoxidase method and reacted with diaminobenzidine. For acetylcholinesterase histochemistry, the tissue was processed by a modification of the direct thiocholine method. Light microscopy of the whole-mounted endolymphatic sacs revealed tyrosine hydroxylase—positive and acetylcholinesterase-positive fibers. Some of the acetylcholinesterase-positive fibers were clearly associated with vessels. This innervation, which has not been described previously, may significantly influence blood flow and function of the endolymphatic sac.

(Arch Otolaryngol Head Neck Surg. 1992;118:260-264)

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