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Published on: September 21, 2021
Effect of topical application of nitroglycerin on cochlear blood flow
A Ito1, T Nakashima, N Yanagita
1Department of Otorhinolaryngology, Nagoya University School of Medicine, Japan.
Purpose:
To investigate whether topical application of the vasodilator nitroglycerin would increase cochlear blood flow without adversely affecting inner ear function.
Materials And Methods:
The effect of topical application of nitroglycerin to the round window membrane on cochlear blood flow was measured in 33 guinea pigs with a laser Doppler flowmeter. Endocochlear potential, as an indicator of inner ear function, was recorded by a glass microelectrode inserted through the round window membrane in a second series of 27 guinea pigs. Blood pressure was also monitored in both experiments.
Results:
Low doses (0.0001 to 1 microgram) of nitroglycerin induced an increase in cochlear blood flow with no change in blood pressure. The cochlear blood flow was maximally increased by approximately 50%. A high dose (50 micrograms) of nitroglycerin induced a significant decrease in blood pressure but did not significantly affect endocochlear potential.
Conclusions:
Topical application of nitroglycerin may be useful in increasing cochlear blood flow in various inner ear diseases.
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