[Function of the upper esophageal sphincter after denervation of recurrent laryngeal nerves and intramural nerves of the cervical esophagus in dogs].
The upper esophageal sphincter prevents reflux into the pharynx. If it functions improperly, aspiration pneumonia can result. We studied the functioning of the sphincter in unanesthetized dogs after denervation under anesthesia of the recurrent laryngeal nerves. The pressure of the sphincter at rest was measured by manometry with a transducer that measured pressure around the tip of a catheter. Then the pressure in response to inflation of a balloon to the diameter of 1.5, 2.0 and 2.5 cm at 5 and 10 cm aboral to the sphincter was measured. Next, the pressure during perfusion of 0.1 N HCl or NaOH 10 cm aboral to the sphincter was measured. These studies were done first in 10 dogs that had undergone only gastrostomy for measurements (controls). Measurements were repeated after the left recurrent laryngeal nerve in the controls was cut (L group), after the right recurrent laryngeal nerve in the L group was cut (B group), and after transection of the esophagus 7 cm aboral to the sphincter in the B group (T group). The differences in the pressure at rest were not significant. In each group, balloon inflation to any diameter tested and at either position made the pressure rise above that at rest. This pressure in the L, B, and T groups, however, was significantly lower than in the controls. When the balloon was inflated to 2.5 cm when it was 10 cm aboral to the sphincter, the pressure in the T group was significantly lower than in the B group. When HCl or NaOH were perfused, the pressure increased gradually in the controls, but not in the other groups. In conclusion, although recurrent laryngeal nerves did not affect the function of the sphincter at rest, they were the afferent routes of the contraction by the sphincter as a reflex following distension or chemical stimulation of the esophagus. The intramural nerve network of the cervical esophagus may be another reflex route of contraction of the upper esophageal sphincter.
Second Department of Surgery, Osaka City University Medical School, Japan.
Y
Y
Fukunaga
M
M
Higashino
H
H
Osugi
T
T
Tokuhara
H
H
Kinoshita
D000818:Animals; D002404:Catheterization; D003714:Denervation; D004285:Dogs; D004943:Esophagogastric Junction / Q000187:drug effects / Q000502:physiology*; D004947:Esophagus / Q000294:innervation*; D006851:Hydrochloric Acid / Q000494:pharmacology; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects; D010812:Physical Stimulation; D012009:Recurrent Laryngeal Nerve / Q000502:physiology*; D012018:Reflex; D012972:Sodium Hydroxide / Q000494:pharmacology
D012972:Sodium Hydroxide; D006851:Hydrochloric Acid