Ann Otol 85: 1976
VIDIAN NERVE AND THE EUSTACHIAN TUBE
E. NATHANSON, M.D. R. T. JACKSON, PH.D.
STEVEN
ATLANTA, GEORGIA
SUMMARY - The vidian nerve was stimulated electrically in the dog and this resulted in a reduced patency of the Eustachian tube. The effect was atropine resistant. This physiological evidence in the dog corresponds to anatomical evidence in man of a parasympathetic, vasodilator nerve bundle passing through the vidian to the sphenopalatine ganglion and then via the pharyngeal nerve to the Eustachian tube mucosa. Additional parasympathetic routes to the tube may exist.
The autonomic innervation of the Eustachian tube has not received much attention. In the dog, the cervical sympathetic nerve has been stimulated and results in an increased patency of the tube.' This increased patency is presumably due to a vasoconstriction in the mucosal lining. We wished to stimulate the parasympathetic component to determine if it induced the opposite reaction. Descriptions of the probable pathways were sparse and conflicting. It was decided to stimulate the vidian nerve to see if it contained vasodilator fibers to the Eustachian tube.
RESULTS
In all five animals, electrical stimulation of the vidian nerve raised the perfusion pressure of the Eustachian tube. Because of the timecourse and response characteristics, it was felt that the response was due to a vasodilation in the mucosa of the tube. The size of the response was related to the stimulus strength (Fig. 1). ~ E E
~ 15
~
g:
10 VIDlAN NERVE
METHODS AND MATERIALS
STIMULATION
5
The experiment was performed on five mongrel dogs that were anesthetized with sodium pentobarbital. The external ear canal was cleaned and the tympanic membrane was removed. A 2 em glass tube inside of a Foley catheter tip was inserted into the external ear canal and secured with a pursestring suture. The glass tube was attached by plastic tubing to an infusion pump" and a pressure transducer..... Ringer's solution was perfused through the Eustachian tube at a constant rate of 1.9 ml/min. The pressure necessary to force the fluid through the Eustachian tube was recorded, as was the femoral blood pressure. The vidian nerve was dissected using the infraorbital approach.
f- 20 -l
sec
A PERFUSION ON
Fig. 1. The effect of changing the stimulus strength on the response of the Eustachian tube to vidian nerve stimulation. Three responses to vidian nerve stimulation are shown. The smallest response was induced by 5V, 5/sec. The middle response was induced by 5V, lO/sec. The largest (and maximum) response was induced by lOY, lO/sec. A maximum response to epinephrine is included for comparison.
.. Harvard Apparatus Co., Inc., Millis, Mass. .... Narco Bio-Systems, Inc., Houston, Texas. From the Division of Otolaryngology, Emory Univ. School of Medicine, Atlanta, Ga. Supported by NIH # NS 09570.
83
Downloaded from aor.sagepub.com at Bobst Library, New York University on May 10, 2015
84
NATHANSON-JACKSON
Attempts to block the eHects of electrical stimulation with atropine sulfate in doses as high as 1 mg/kg were unsuccessful.
CENTRAL
2I
------:\\~ ~--
VIOIAN NERVE
SPHENOPALATINE GANGLION
3~
Cutting the cervical sympathetic nerve resulted in an immediate decrease in patency. If, after cutting the cervical sympathetic nerve, the vidian nerve is cut, no change in patency occurs (Fig. 3).
•
·Y--:-r 4-\ \
MAXILLARY NERVE
PERIPHERAL
DISCUSSION
Fig. 2. The responses of Eustachian tube perfusion pressure designated 1-4 were obtained by stimulating the central end of the cut vidian nerve (1), the distal end of the cut vidian nerve (2), the sphenopalatine ganglion (3), and the cut peripheral end of the maxillary nerve (4).
'"
:r
E E 15 ILl
n:
::::l (J)
f3n:
10
CUT CERVICAL
0..
SYMPATHETIC
z o u; 5
CUT VIOl AN NERVE
::::l
u,
n:
ILl 0..
A PERFUSION ON
Fig. 3. The change in Eustachian tube perfusion pressure obtained from cutting the cervical sympathetic nerve and the vidian nerve in the same animal.
If the intact vidian nerve was stimulated, the Eustachian tube response occurred but was usually accompanied by respiratory movements and shudders. The latter were induced by the simultaneous stimulation of sensory fibers in the vidian nerve. If the vidian nerve was cut and the distal end stimulated, the reflex response disappeared but the tube response remained. Stimulation of the sphenopalatine ganglion caused the "vasodilation" response. Stimulation of the cut distal end of the maxillary nerve gave no Eustachian tube response (Fig. 2).
The vidian nerve, known to contain vasodilator and secretory fibers to the nasal mucosa.s also appears to contain vasodilator fibers to the tube. The present finding corresponds to the anatomical evidence presented by Warwick and Williams" and Proctor." According to Warwick and Williams, the nerves of the tube spring from the tympanic plexus and from the pharyngeal branch of the pterygopalatine (sphenopalatine) ganglion. The precise contribution from the nerves which form the plexus, i.e., the glossopharyngeal, the cervical sympathetic, and possibly the facial, remains uncertain in man. The pharyngeal nerve, a small branch, arises from the posterior part of the sphenopalatine ganglion, passes through the palatinovaginal canal with the pharyngeal branch of the maxillary artery, and is distributed to the m'lCOUS membrane of the nasal part of the pharynx behind the auditory tubes Apparently, it is also distributed to the lining of the tube. Proctor states that the innervation of the tubal mucosa is dependent on the sphenopalatine ganglion ( pharyngeal nerve of Bock), the otic ganglion (submucosal branch of the tensor veli palatini nerve), the petrosal nerves ( greater superficial petrosal and paired facial), Jacobson's nerve (paired glossopharyngeal), and the caroticotympanic nerve." Mitchell suggests that the tympanic branch of the glossopharyngeal nerve may contain vasodilator fibers to the mucosa of the Eustachian tube." He also mentions the difficulty in following the fiber connections in the tympanic plexus. Most probably, the
Downloaded from aor.sagepub.com at Bobst Library, New York University on May 10, 2015
VIVIAN NERVE AND THE EUSTACHIAN TUBE
sympathetic fibers from the cervical ganglion course through this area. Further evidence is needed before we know if additional vasodilator fibers are also mixed in this delicate complex. Since high doses of atropine did not block the effects of vidian stimulation, the nerve junction must either be
85
"atropine resistant" or not cholinergic. The decrease in patency that resulted from cutting the cervical sympathetic nerve implies that there is a sympathetic tone on the blood vessels in the tube mucosa. Since cutting the vidian nerve had no effect on the patency, a lack of parasympathetic tone is implied.
Request for reprints should be sent to R. T. Jackson, Ph.D., 441 Woodruff Memorial Bldg., Atlanta, Ga. 30322. REFERENCES 1. Jackson RT: Pharmacological mechanisms in the Eustachian Tube. Ann Otol Rhinol Laryngol 80:313-318, 1971 2. Eccles R, 'Wilson H: The autonomic innervation of the nasal blood vessels of the cat. J Physiol 238:549-560,1974 3. Warwick R, Williams PL: Gray's Anat-
omy, 35th British Ed. Philadelphia, Saunders,
1973, p 1007 4. Proctor B: Embryology and anatomy of the Eustachian tube. Arch Otolaryngol 86: 503-514, 1967 5. Mitchell GAG: The autonomic nerve supply of the throat, nose and ear. J Laryng Otol 68:495-516, 1954
XI WORLD CONGRESS OF OTORHINOLARYNGOLOGY The XI W orId Congress of Otorhinolaryngology will be held in Buenos Aires, Argentina, March 13-19, 1977. The four types of activities will include: plenary, regular, free communications and lecture sessions. At the plenary sessions the central themes will be immunity in O.R.L., Corti organ, paralysis of vocal cord, otological problems in space Hight, and social, economic, community and legal problems relating to O.R.L. Regular sessions will explore various themes chosen by the Committee. There will be symposia, round tables, workshops, scientific exhibits, audio-visual exhibits and films. Official tourist agency - Delfino Turismo, Calle San Martin 427, Buenos Aires, Argentina. The Congress Secretariat is Ceni, S.A., Avda. Roque Saenz Pena 1110, 2° Piso, Buenos Aires, Argentina.
Downloaded from aor.sagepub.com at Bobst Library, New York University on May 10, 2015
VIDIAN NERVE AND THE EUSTACHIAN TUBE
E. NATHANSON, M.D. R. T. JACKSON, PH.D.
STEVEN
ATLANTA, GEORGIA
SUMMARY - The vidian nerve was stimulated electrically in the dog and this resulted in a reduced patency of the Eustachian tube. The effect was atropine resistant. This physiological evidence in the dog corresponds to anatomical evidence in man of a parasympathetic, vasodilator nerve bundle passing through the vidian to the sphenopalatine ganglion and then via the pharyngeal nerve to the Eustachian tube mucosa. Additional parasympathetic routes to the tube may exist.
The autonomic innervation of the Eustachian tube has not received much attention. In the dog, the cervical sympathetic nerve has been stimulated and results in an increased patency of the tube.' This increased patency is presumably due to a vasoconstriction in the mucosal lining. We wished to stimulate the parasympathetic component to determine if it induced the opposite reaction. Descriptions of the probable pathways were sparse and conflicting. It was decided to stimulate the vidian nerve to see if it contained vasodilator fibers to the Eustachian tube.
RESULTS
In all five animals, electrical stimulation of the vidian nerve raised the perfusion pressure of the Eustachian tube. Because of the timecourse and response characteristics, it was felt that the response was due to a vasodilation in the mucosa of the tube. The size of the response was related to the stimulus strength (Fig. 1). ~ E E
~ 15
~
g:
10 VIDlAN NERVE
METHODS AND MATERIALS
STIMULATION
5
The experiment was performed on five mongrel dogs that were anesthetized with sodium pentobarbital. The external ear canal was cleaned and the tympanic membrane was removed. A 2 em glass tube inside of a Foley catheter tip was inserted into the external ear canal and secured with a pursestring suture. The glass tube was attached by plastic tubing to an infusion pump" and a pressure transducer..... Ringer's solution was perfused through the Eustachian tube at a constant rate of 1.9 ml/min. The pressure necessary to force the fluid through the Eustachian tube was recorded, as was the femoral blood pressure. The vidian nerve was dissected using the infraorbital approach.
f- 20 -l
sec
A PERFUSION ON
Fig. 1. The effect of changing the stimulus strength on the response of the Eustachian tube to vidian nerve stimulation. Three responses to vidian nerve stimulation are shown. The smallest response was induced by 5V, 5/sec. The middle response was induced by 5V, lO/sec. The largest (and maximum) response was induced by lOY, lO/sec. A maximum response to epinephrine is included for comparison.
.. Harvard Apparatus Co., Inc., Millis, Mass. .... Narco Bio-Systems, Inc., Houston, Texas. From the Division of Otolaryngology, Emory Univ. School of Medicine, Atlanta, Ga. Supported by NIH # NS 09570.
83
Downloaded from aor.sagepub.com at Bobst Library, New York University on May 10, 2015
84
NATHANSON-JACKSON
Attempts to block the eHects of electrical stimulation with atropine sulfate in doses as high as 1 mg/kg were unsuccessful.
CENTRAL
2I
------:\\~ ~--
VIOIAN NERVE
SPHENOPALATINE GANGLION
3~
Cutting the cervical sympathetic nerve resulted in an immediate decrease in patency. If, after cutting the cervical sympathetic nerve, the vidian nerve is cut, no change in patency occurs (Fig. 3).
•
·Y--:-r 4-\ \
MAXILLARY NERVE
PERIPHERAL
DISCUSSION
Fig. 2. The responses of Eustachian tube perfusion pressure designated 1-4 were obtained by stimulating the central end of the cut vidian nerve (1), the distal end of the cut vidian nerve (2), the sphenopalatine ganglion (3), and the cut peripheral end of the maxillary nerve (4).
'"
:r
E E 15 ILl
n:
::::l (J)
f3n:
10
CUT CERVICAL
0..
SYMPATHETIC
z o u; 5
CUT VIOl AN NERVE
::::l
u,
n:
ILl 0..
A PERFUSION ON
Fig. 3. The change in Eustachian tube perfusion pressure obtained from cutting the cervical sympathetic nerve and the vidian nerve in the same animal.
If the intact vidian nerve was stimulated, the Eustachian tube response occurred but was usually accompanied by respiratory movements and shudders. The latter were induced by the simultaneous stimulation of sensory fibers in the vidian nerve. If the vidian nerve was cut and the distal end stimulated, the reflex response disappeared but the tube response remained. Stimulation of the sphenopalatine ganglion caused the "vasodilation" response. Stimulation of the cut distal end of the maxillary nerve gave no Eustachian tube response (Fig. 2).
The vidian nerve, known to contain vasodilator and secretory fibers to the nasal mucosa.s also appears to contain vasodilator fibers to the tube. The present finding corresponds to the anatomical evidence presented by Warwick and Williams" and Proctor." According to Warwick and Williams, the nerves of the tube spring from the tympanic plexus and from the pharyngeal branch of the pterygopalatine (sphenopalatine) ganglion. The precise contribution from the nerves which form the plexus, i.e., the glossopharyngeal, the cervical sympathetic, and possibly the facial, remains uncertain in man. The pharyngeal nerve, a small branch, arises from the posterior part of the sphenopalatine ganglion, passes through the palatinovaginal canal with the pharyngeal branch of the maxillary artery, and is distributed to the m'lCOUS membrane of the nasal part of the pharynx behind the auditory tubes Apparently, it is also distributed to the lining of the tube. Proctor states that the innervation of the tubal mucosa is dependent on the sphenopalatine ganglion ( pharyngeal nerve of Bock), the otic ganglion (submucosal branch of the tensor veli palatini nerve), the petrosal nerves ( greater superficial petrosal and paired facial), Jacobson's nerve (paired glossopharyngeal), and the caroticotympanic nerve." Mitchell suggests that the tympanic branch of the glossopharyngeal nerve may contain vasodilator fibers to the mucosa of the Eustachian tube." He also mentions the difficulty in following the fiber connections in the tympanic plexus. Most probably, the
Downloaded from aor.sagepub.com at Bobst Library, New York University on May 10, 2015
VIVIAN NERVE AND THE EUSTACHIAN TUBE
sympathetic fibers from the cervical ganglion course through this area. Further evidence is needed before we know if additional vasodilator fibers are also mixed in this delicate complex. Since high doses of atropine did not block the effects of vidian stimulation, the nerve junction must either be
85
"atropine resistant" or not cholinergic. The decrease in patency that resulted from cutting the cervical sympathetic nerve implies that there is a sympathetic tone on the blood vessels in the tube mucosa. Since cutting the vidian nerve had no effect on the patency, a lack of parasympathetic tone is implied.
Request for reprints should be sent to R. T. Jackson, Ph.D., 441 Woodruff Memorial Bldg., Atlanta, Ga. 30322. REFERENCES 1. Jackson RT: Pharmacological mechanisms in the Eustachian Tube. Ann Otol Rhinol Laryngol 80:313-318, 1971 2. Eccles R, 'Wilson H: The autonomic innervation of the nasal blood vessels of the cat. J Physiol 238:549-560,1974 3. Warwick R, Williams PL: Gray's Anat-
omy, 35th British Ed. Philadelphia, Saunders,
1973, p 1007 4. Proctor B: Embryology and anatomy of the Eustachian tube. Arch Otolaryngol 86: 503-514, 1967 5. Mitchell GAG: The autonomic nerve supply of the throat, nose and ear. J Laryng Otol 68:495-516, 1954
XI WORLD CONGRESS OF OTORHINOLARYNGOLOGY The XI W orId Congress of Otorhinolaryngology will be held in Buenos Aires, Argentina, March 13-19, 1977. The four types of activities will include: plenary, regular, free communications and lecture sessions. At the plenary sessions the central themes will be immunity in O.R.L., Corti organ, paralysis of vocal cord, otological problems in space Hight, and social, economic, community and legal problems relating to O.R.L. Regular sessions will explore various themes chosen by the Committee. There will be symposia, round tables, workshops, scientific exhibits, audio-visual exhibits and films. Official tourist agency - Delfino Turismo, Calle San Martin 427, Buenos Aires, Argentina. The Congress Secretariat is Ceni, S.A., Avda. Roque Saenz Pena 1110, 2° Piso, Buenos Aires, Argentina.
Downloaded from aor.sagepub.com at Bobst Library, New York University on May 10, 2015
