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- Title
Effect of body position, epinephrine, and a surface-tension-lowering substance on the eustachian tube opening in the rat.
- Authors
Malm, Lars; Tjernström, Örjan; White, Peter; Ivarsson, Alf; Malm, L; Tjernström, O; White, P; Ivarsson, A
- Abstract
The middle ear pressure was increased by air injections and the level (pressure opening level = Pol) at which the Eustachian tube (ET) opened was determined in anaesthetized ras. At a rate of pressure increase of 0.7 kPa/s it opened at 4.1 +/- 0.4 kPa. A change of the body and head position from horizontal to almost vertical increased the Pol by about 0.4 kPa (head downwards) and decreased the Pol by about 0.3 kPa (head upwards). Epinephrine tested in a dose-response experiment had no significant effect on Pol (doses from 0.01 to 10 micrograms/kg body weight). A surface-tension-lowering substance, Tween 20, instilled into the middle ear, reduced Pol by about 1 kPa. A change in body and head position had thus a moderate effect on the passive opening of the ET, a strong decongestant had no effect, and a surface-lowering substance, a marked effect. With increasing rates of pressure change in the middle ear, Pol increased. After instillation of Tween 20 there was an almost parallel shift to lower values of the regression line of the Pol at different rates of pressure increase.
- Subjects
ADRENALINE; ANIMAL experimentation; COMPARATIVE studies; EUSTACHIAN tube; RESEARCH methodology; MEDICAL cooperation; POSTURE; RATS; RESEARCH; EVALUATION research; PHYSIOLOGY
- Publication
ORL, 1987, Vol 49, Issue 3, p138
- ISSN
0301-1569
- Publication type
journal article
- DOI
10.1159/000275924