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Cochlear action potentials threshold and systemic arterial pO2
Author(s) -
Hildesheimer Minka,
Muchnik Chava,
Rubinstein Moshe
Publication year - 1987
Publication title -
the laryngoscope
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.181
H-Index - 148
eISSN - 1531-4995
pISSN - 0023-852X
DOI - 10.1288/00005537-198702000-00012
Subject(s) - hypoxemia , arterial blood , stimulus (psychology) , chemistry , oxygen , medicine , anesthesia , cardiology , psychology , organic chemistry , psychotherapist
A progressive decrease in arterial p O 2 was induced in Hartley guinea pigs (GP) by having them rebreathe the air entrapped in a closed circuit from which the CO 2 was continuously absorbed. Following this slow‐developing hypoxemia, a sequence of events concerning the ear could be observed. Firstly, a fluctuation in cochlear action potentials (CAP) was noted. This appeared only at stimulus intensities near the threshold and was not evident at higher intensities. At a mean arterial p O 2 level of 30 mm Hg, this phenomenon was observed in 60% of the GP. At a mean p O 2 of 24.66 mm Hg, a shift in threshold occurred in all GP. Finally, when the blood p O 2 reached an average of 14.92 mm Hg, no CAP response could be elicited, even at click intensity of 120 dB SPL. The 30 mm Hg oxygen concentration in the arterial blood was considered as a “critical level” at which the cochlear function starts to deteriorate in guinea pigs.