Electron-microscopic observation of adrenergic innervation in guinea pig Eustachian tube

The precise locations of adrenergic nerve terminals in the Eustachian tube of guinea pigs have, for the first time, been demonstrated by electron microscopy, with application of a false transmitter (5-OHDA). Adrenergic nerve terminals were found in abundance near the arteries in each area of the Eustachian tube. In particular, these terminals were observed just beneath the smooth muscle layer of the arteries. The exact locations of adrenergic nerve terminals in the submucous and gland region are also discussed.