Effect of Loud Sound Exposure on the Cochlear Blood Flow

Okamoto, A.; Tamura, Toshiyo; Yokoyama, Kazunori; Kimura, Noriaki; Hasegawa, Makoto

doi:10.3109/00016489009125158

Cited by 20 publications

(11 citation statements)

References 8 publications

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“…As expected, in the immobilized, anaesthetized GPs, the additional stressor-sound exposure did not increase the value of MBP, PR, or NE. Similar results were reported in rats (16,17) and in GPs (18).…”

Section: Discussionsupporting

confidence: 90%

Stress Reaction to Intense Sound Exposure Under Different Arousal Levels in Guinea Pigs

Muchnik

Rosenthal²,

Peleg³

et al. 1998

Acta Oto-Laryngologica

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The general impact of high intensity sound exposure on 25 guinea pigs was investigated at three different levels of arousal: 10 during general anaesthesia. 10 during partial arousal, and 5 during complete arousal. Parameters recorded before and during noise exposure were mean arterial blood pressure, pulse rate, and plasma norepinephrine levels. The anaesthetized group showed no increase in the three parameters during sound exposure. Under partial arousal, pulse rate and norepinephrine level increased significantly: pulse rate from 224.5 beats/min before exposure to 278.6 beats/min during exposure, and norepinephrine level from 558 pg/ml before sound exposure to 1276 pg/ml during exposure. At the time of the complete arousal state norepinephrine and pulse rates increased significantly during noise exposure, while blood pressure showed no additional increase as a result of sound exposure.

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Section: Discussionsupporting

confidence: 90%

Stress Reaction to Intense Sound Exposure Under Different Arousal Levels in Guinea Pigs

Muchnik

Rosenthal²,

Peleg³

et al. 1998

Acta Oto-Laryngologica

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“…We confirm with our investigation the findings which have been made by means of Laser Doppler flowmetry under comparable noise exposures [1,16], In that way the reduction of guinea pig CBF above 100 dB SPL noise exposure was reproduced in addition to Laser Doppler flowmetry by means of hydrogen clearance. In connec tion with this, it is of interest that the Mongolian gerbil CBF shows a slight increase by 85 dB SPL noise expo sure, whereas by 105 dB SPL no change in CBF from the initial CBF level occurs [5], Under intensive noise expo sure (> 100 dB SPL) it could be possible that a protec tive mechanism via CBF reduction diminishes the evoked metabolism and therefore the accumulation of toxic metabolic by-products [5].…”

Section: Discussionsupporting

confidence: 80%

Guinea Pig Cochlear Blood Flow under Definite Sound Exposure-Hydrogen Clearance Measurement

Meyer

Kühl

Schmidt

et al. 1991

ORL

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Blood flow measurements were carried out on 18 coloured guinea pigs (8 animals served as control group) before and during definite sound exposure (12 kHz, 110 dB SPL). The exposure time amounted to 60 min. The anaesthesia was carried out according to the following schedule: a mixture consisting of 70 mg α-chloralose/kg b.w. and 400 mg urethane/kg b.w. was injected intraperitoneally. The relaxation was performed by means of i.p. application of 3 mg Tricuran/kg b.w./h. The hydrogen clearance measurements (HCM) were carried out under artificial respiration with control of arterial pH, endexpiratory CO₂ content, as well as blood pressure and body temperature. After a duration of noise exposure of 30–45 min the cochlear blood flow reached an average level of 80% of the initial point. This level remained mainly unchanged until the end of noise exposure (60 min). Our HMC’s confirm Laser Doppler flowmetry findings.

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“…The effects of the administration of vasoactive agents (9,19), sound overstimulation (20) and anoxia (7,8) on the CBF with the use of the laser Doppler system have been examined in many studies. The conventional LDF, however, cannot simultaneously measure the regional CBF changes during the induction of the damage to the focal cochlear microcirculation, since the laser probe contacts the cochlear surface and hinders the green light illumination.…”

Section: Discussionmentioning

confidence: 99%

Focal Damage to Cochlear Microcirculation Measured using a Non-Contact Laser Blood Flowmeter in Guinea Pigs

Iwasaki

Nagura²,

Miyashita³

et al. 1998

Acta Oto-Laryngologica

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The focal microcirculation damage induced by a photochemical reaction in the stria vascularis (SV) of the guinea pig cochlea was evaluated using a non-contact laser blood flowmeter (NCLBF) and the endocochlear potential (EP). Focal degeneration, including vascular thrombosis in the SV produced by the systemic infusion of rose bengal, and the illumination of green light in the second cochlear turn were observed with scanning and transmission electron microscopy. The NCLBF probe was placed at a position 10 mm from the cochlear surface, and the diameter of the laser light was focused to 1 mm in the green light illumination area. The change in NCLBF values induced by the loading of anoxia and administration of epinephrine agreed very well with those obtained with a conventional contact-type laser Doppler flowmeter. Significant decreases in the cochlear blood flow (CBF) (p < 0.01) and EP (p < 0.01) were observed at the site of the photochemical injury compared with the values at the non-illuminated area. CBF gradually decreased (82.0+/-7.3% at 10 min, 71.2+/-5.5% at 20 min, 64.3+/-11.2% at 30 min from the baseline, n=7), but blood pressure was stable. The EP values also decreased gradually during the first 13 min (79.9+/-3.7 mV at pre-illumination, 11.4+/-10.7 mV at 13 min, n=7). The gradual decline in the EP was comparable to the changes in the CBF. The NCLBF was useful for evaluating the haemodynamic properties of the cochlear microcirculation disorders, and this animal model is expected to be suitable for studying the pathology of focal cochlear vascular disease.

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Effect of Loud Sound Exposure on the Cochlear Blood Flow

Cited by 20 publications

References 8 publications

Stress Reaction to Intense Sound Exposure Under Different Arousal Levels in Guinea Pigs

Stress Reaction to Intense Sound Exposure Under Different Arousal Levels in Guinea Pigs

Guinea Pig Cochlear Blood Flow under Definite Sound Exposure-Hydrogen Clearance Measurement

Focal Damage to Cochlear Microcirculation Measured using a Non-Contact Laser Blood Flowmeter in Guinea Pigs

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