V Adrenergic Innervation of the Cochlea

NADPH-diaphorase histochemistry reveals an autonomic-like innervation in the postnatal hamster cochlea

“…4B). By P8, nonperivascular fibers in basal and apical regions were found near the habenula perforata where they formed a dense plexus, similar to previous descriptions of sympathetic fibers (Spoendlin and Lichtensteiger, 1966;Terayama et al, 1966). By P12, nonperivascular fibers were observed in apical regions of the cochlea.…”

“…These fibers shared morphological characteristics with, and appeared nearly identical to, sympathetic fibers first detected by using the Falck-Hillarp method and transmission electron microscopy (Spoendlin and Lichtensteiger, 1966;Terayama et al, 1966;Densert and Flock, 1974;Densert, 1974). Adrenergic fibers are known to display a strong amine fluorescence signal and course either along blood vessels (perivascular) or move along cochlear nerve tracts (nonperivascular).…”

“…The presence of autonomic innervation in the organ of Corti may imply some sort of paracrine interaction with hair cells or supporting cells (Fessenden and Schacht, 1997). Most studies of catecholaminergic innervation in the cochlea fail to report adrenergic fibers in the organ of Corti (Spoendlin and Lichtensteiger, 1966;Terayama et al, 1966;Densert and Flock, 1974;Eybalin et al, 1983Eybalin et al, , 1993Jones et al, 1987;Brechtelsbauer et al, 1990;Shibamori et al, 1994). In adult animals, there are reports of fibers demonstrating immunoreactivity to tyrosine hydroxylase and dopamine beta-hydroxylase in the organ of Corti but these studies suggest that they belong to the olivocochlear efferent system (Vinnikov et al, 1966;Jones et al, 1987;Usami et al, 1988;d'Aldin et al, 1995).…”

Cation Transport and Cochlear Function

“…These fibres lose their myelin sheath before they enter the cortilymph space. The innervation pattern of the hair cells has been described extensively by Smith and Sjostrand (1961) and Spoendlin (1967bSpoendlin ( , 1969 The adrenergic innervation consists of a dense perivascular network in the modiolus but these only accompany the vessels which course to the organ of Corti (Terrayama et al, 1966).…”

Adrenergic Innervation of the Eustachian Tube

“…Although autonomic innervation of the nose [3] and the inner ear [4,5] has been extensively investigated, knowledge of the distribution of the adrenergic nerve fibers in the Eustachian tube is incomplete. Demon stration of adrenergic innervation of the Eu stachian tube using Falck-Hillarp's histo chemical method [6] and glyoxylic acid method [7] has been reported recently by Uddman et al [8] and the authors of the present paper [9.…”