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[The effect of CO2 and apnea on cochlear and middle ear blood flow in guinea pigs].
Nihon Jibiinkoka Gakkai Kaiho. 1997 Jan; 100(1):36-44.NJ

Abstract

The effect of 10% CO2 (in air) and apnea on cochlear blood flow (CBF) and middle ear blood flow (MEBF), capillary vessel diameters and blood pressure (BP) were investigated in guinea pigs. Intravital microscopic techniques (IVM) using video system, and laser Doppler flowmetry (LD) were used. MEBF was measured in the blood vessels of the middle ear mucosa over the cochlea and CBF was measured in the lateral wall vessels in the second or third cochlear turn. During 10% CO2 respiration for 10 min, the highest vessel diameter dilated about 11% in the middle ear and 5% in the cochlea. During 5 minutes apnea, the highest vessel diameter constricted about 30% in the middle ear and 5% in the cochlea. Elevation of PCO2 dilate blood vessels with constant PO2, but constriction of blood vessels as observed in extremely low PO2 range even if PCO2 was elevated. The ratio of the change in blood flow volume to the change in BP was obtained after the change in blood flow volume was calculated from blood flow velocity and blood vessel diameter. The mean change of ratio in MEBF was a 10% decrease with 10% CO2, 28% decrease with apnea in IVM. The mean change of ratio in CBF was a 44% increase with 10% CO2, 14% increase with apnea in IVM, 67% increase with 10% CO2, 42% increase with apnea, in LD. The change of CBF in LD was about 20% larger than in IVM. Our results showed that CBF belonging to vertebral artery system was more strongly maintained in association with autoregulation even under conditions of low PO2 or high PCO2 compared to MEBF in the external carotid artery system. It was suggested that blood flow behavior was significantly different between the middle ear and inner ear.

Authors+Show Affiliations

Department of Otorhinolaryngology, Nagoya University School of Medicine.No affiliation info availableNo affiliation info available

Pub Type(s)

English Abstract
Journal Article

Language

jpn

PubMed ID

9038074

Citation

Yamamoto, J, et al. "[The Effect of CO2 and Apnea On Cochlear and Middle Ear Blood Flow in Guinea Pigs]." Nihon Jibiinkoka Gakkai Kaiho, vol. 100, no. 1, 1997, pp. 36-44.
Yamamoto J, Nakashima T, Yanagita N. [The effect of CO2 and apnea on cochlear and middle ear blood flow in guinea pigs]. Nihon Jibiinkoka Gakkai Kaiho. 1997;100(1):36-44.
Yamamoto, J., Nakashima, T., & Yanagita, N. (1997). [The effect of CO2 and apnea on cochlear and middle ear blood flow in guinea pigs]. Nihon Jibiinkoka Gakkai Kaiho, 100(1), 36-44.
Yamamoto J, Nakashima T, Yanagita N. [The Effect of CO2 and Apnea On Cochlear and Middle Ear Blood Flow in Guinea Pigs]. Nihon Jibiinkoka Gakkai Kaiho. 1997;100(1):36-44. PubMed PMID: 9038074.
* Article titles in AMA citation format should be in sentence-case
TY - JOUR T1 - [The effect of CO2 and apnea on cochlear and middle ear blood flow in guinea pigs]. AU - Yamamoto,J, AU - Nakashima,T, AU - Yanagita,N, PY - 1997/1/1/pubmed PY - 1997/1/1/medline PY - 1997/1/1/entrez SP - 36 EP - 44 JF - Nihon Jibiinkoka Gakkai kaiho JO - Nihon Jibiinkoka Gakkai Kaiho VL - 100 IS - 1 N2 - The effect of 10% CO2 (in air) and apnea on cochlear blood flow (CBF) and middle ear blood flow (MEBF), capillary vessel diameters and blood pressure (BP) were investigated in guinea pigs. Intravital microscopic techniques (IVM) using video system, and laser Doppler flowmetry (LD) were used. MEBF was measured in the blood vessels of the middle ear mucosa over the cochlea and CBF was measured in the lateral wall vessels in the second or third cochlear turn. During 10% CO2 respiration for 10 min, the highest vessel diameter dilated about 11% in the middle ear and 5% in the cochlea. During 5 minutes apnea, the highest vessel diameter constricted about 30% in the middle ear and 5% in the cochlea. Elevation of PCO2 dilate blood vessels with constant PO2, but constriction of blood vessels as observed in extremely low PO2 range even if PCO2 was elevated. The ratio of the change in blood flow volume to the change in BP was obtained after the change in blood flow volume was calculated from blood flow velocity and blood vessel diameter. The mean change of ratio in MEBF was a 10% decrease with 10% CO2, 28% decrease with apnea in IVM. The mean change of ratio in CBF was a 44% increase with 10% CO2, 14% increase with apnea in IVM, 67% increase with 10% CO2, 42% increase with apnea, in LD. The change of CBF in LD was about 20% larger than in IVM. Our results showed that CBF belonging to vertebral artery system was more strongly maintained in association with autoregulation even under conditions of low PO2 or high PCO2 compared to MEBF in the external carotid artery system. It was suggested that blood flow behavior was significantly different between the middle ear and inner ear. SN - 0030-6622 UR - https://www.unboundmedicine.com/medline/citation/9038074/[The_effect_of_CO2_and_apnea_on_cochlear_and_middle_ear_blood_flow_in_guinea_pigs]_ L2 - http://www.medicalonline.jp/meteo_linkout.php?issn=0030-6622&volume=100&issue=1&spage=36 DB - PRIME DP - Unbound Medicine ER -