ラット内耳のCO_2に対する血流増加反応の加齢変化 [in Japanese] Age-related CO_2 Reactivity of the Inner Ear Blood Flow in Rats [in Japanese]
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It has recently been demonstrated that the inner ear has a chemical control mechanism to regulate blood flow adequately, as in central organs. Impairment of blood flow regulation is supposed to be a cause of vertigo or hearing disturbance especially in elderly patients. In the present study, we investigated age-related impairment of chemical regulation in the inner ear. Using rats, cochlear blood flow (CoBF) was measured by laser Doppler flowmetry and chemical control was evaluated by blood flow reactivity to 7% CO<SUB>2</SUB> + air inhalation. CoBF of young rats (2-to 3-month old) increased to 130±7.3% of pre-inhalation (mean± SE), aged rats (12-to 14-month old) to 123 ±2.9. Chemical Vasomotor index (Cl : ΔCoBF/ΔPCO<SUB>2</SUB>) of young rats was 1.67 ±0.33 (%/mmHg), and that of aged rats was 1.47 ±0.44. As shown by these results, chemical control in the aged group was weaker than that in the young group, although the difference in reactivity was not significant. Considering these results and the literature, we discuss the pathogenesis of vertigo and hearing disturbance in elderly patients.
- Equilibrium Research
Equilibrium Research 57(3), 311-315, 1998-06-01
Japan Society for Equilibrium Research