Asphyxia and diuretic-induced changes in the Ca2+ concentration of endolymph.
Jpn J Physiol
; 53(1): 35-44, 2003 Feb.
Article
en En
| MEDLINE
| ID: mdl-12689356
ABSTRACT
Using Ca2+ -selective microelectrodes based on the neutral carrier, ETH-1001 with polyvinyl chloride (PVC), we have measured changes in the free Ca2+ concentration of guinea pig cochlear endolymph ([Ca](e)) after transient asphyxia or intravenous administration of diuretics. Under the control conditions, the endocochlear potential (EP) was +80 mV, and the [Ca](e) was in the range 1.4 x 10(-7)-2.4 x 10(-6) M (n = 16). Transient asphyxia (1-1.5 min) produced an increase in the [Ca](e) with a fall in the EP, whereas the cessation of the asphyxia led to a quick recovery of both [Ca](e) and EP to their control levels. Intravenous administration of furosemide (60 mg/kg) or bumetanide (30 mg/kg) also caused an increase in the [Ca](e) with a fall in the EP, followed by a gradual recovery of both [Ca](e) and EP. From these results, we obtained a significant correlation between EP and p[Ca](e) (= -log[Ca](e)), and conclude that (1) the [Ca](e) is extremely low, around 10(-6) M or less, under normal conditions and (2) the [Ca](e) is directly correlated with EP under physiological conditions.
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Bases de datos:
MEDLINE
Asunto principal:
Asfixia
/
Calcio
/
Cóclea
/
Diuréticos
/
Endolinfa
/
Microelectrodos
Límite:
Animals
Idioma:
En
Revista:
Jpn J Physiol
Año:
2003
Tipo del documento:
Article