Effects of anterior inferior cerebellar artery occlusion on cochlear blood flow – a comparison between laser-Doppler and microsphere methods

• Published in: Hearing research Vol. 162; no. 1; pp. 85 - 90
• Main Authors: Nakashima, Tsutomu, Suzuki, Toru, Iwagaki, Toshinori, Hibi, Tatsuya
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 01.12.2001; Elsevier
• Subjects: Animals; Anterior inferior cerebellar artery; Arterial Occlusive Diseases - physiopathology; Biological and medical sciences; Bone blood flow; Cerebellum - blood supply; Cochlea - blood supply; Cochlear blood flow; Ear and associated structures. Auditory pathways and centers. Hearing. Vocal organ. Phonation. Sound production. Echolocation; Fundamental and applied biological sciences. Psychology; Laser-Doppler Flowmetry; Microsphere; Microspheres; Rats; Rats, Wistar; Regional Blood Flow; Skull - blood supply; Vertebrates: nervous system and sense organs; Laser-Doppler flowmetry; Microsphere; Anterior inferior cerebellar artery; Cochlear blood flow; Bone blood flow; Occlusion; Regional blood flow; Rat; Rodentia; Cerebral artery; Inner ear; Organ of hearing; Vertebrata; Laser dopplerometry; Mammalia; Cochlea; Hemodynamics
• ISSN: 0378-5955; 1878-5891
• DOI: 10.1016/S0378-5955(01)00372-0

The effects of anterior inferior cerebellar artery (AICA) occlusion on blood flow were investigated in rats using the laser-Doppler and microsphere methods. A specially designed microclamp was held in a micromanipulator and positioned to occlude the left AICA. After the middle ear mucosa had been removed, a 1.0-mm laser-Doppler probe was placed on the basal turn of the left cochlea. Non-radioactive microspheres were injected intracardially during the AICA occlusion and the numbers of microspheres in various parts of the cochlea were counted, including in the bone surrounding the cochlea. Upon AICA clamping, the blood flow measured by laser-Doppler flowmetry decreased to 46.9±11.9% of the baseline value, and the number of microspheres trapped in the cochlea was 17.2±13.3% compared with the contralateral side in 15 animals. The number of microspheres in the bone surrounding the cochlea in the AICA-clamped side was 81±15% of that of the contralateral side. In animals in which there were few if any microspheres in the cochlea, laser-Doppler output was 30–40% of the baseline value. From these findings, we infer that during complete interruption of cochlear blood flow in rats, residual laser-Doppler output was essentially attributable to blood flow in the bone surrounding the cochlea.