The effect of the sympathetic and sensory nervous system on active eustachian tube function in the rat

Conclusion. We propose that simultaneous activation of the sensory and sympathetic nervous system may adversely affect eustachian tube function, which may have a role in the genesis of Meniere's disease. Objective. We have determined the distribution of sympathetic and nociceptive sensory axons in the mucosa of the rat eustachian tube and investigated whether sympathetic or nociceptive neurons influence the function of the eustachian tube. Materials and methods. We tested whether the ability of a rat to equalize air pressure in the middle ear during evoked swallowing was altered by activation or blockade of the local sympathetic nervous system, or by stimulation of nociceptive neurons with capsaicin. Results. Sympathetic axons were sparse, but CGRP-immunoreactive, nociceptive axons formed a dense subepithelial plexus beneath the eustachian tube epithelium. Neither the adrenergic blocking drug, bretylium, nor electrical stimulation of the superior cervical ganglion significantly altered eustachian tube fun...