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Decreased calcium-activated potassium channels by hypoxia causes abnormal firing in the spontaneous firing medial vestibular nuclei neurons.
- Source :
-
European Archives of Oto-Rhino-Laryngology . Oct2015, Vol. 272 Issue 10, p2703-2711. 9p. - Publication Year :
- 2015
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Abstract
- Vertebrobasilar insufficiency (VBI) presents complex varied clinical symptoms, including vertigo and hearing loss. Little is known, however, about how Ca-activated K channel attributes to the medial vestibular nucleus (MVN) neural activity in VBI. To address this issue, we performed whole-cell patch clamp and quantitative polymerase chain reaction (qPCR) to examine the effects of hypoxia on neural activity and the changes of the large conductance Ca activated K channels (BKCa channels) in the MVN neurons in brain slices of male C57BL/6 mice. Brief hypoxic stimuli of the brain slices containing MVN were administrated by switching the normoxic artificial cerebrospinal fluid (ACSF) equilibrated with 21 % O/5 % CO to hypoxic ACSF equilibrated with 5 % O/5 % CO (balance N). 3-min hypoxia caused a depolarization in the resting membrane potential (RM) in 8/11 non-spontaneous firing MVN neurons. 60/72 spontaneous firing MVN neurons showed a dramatic increase in firing frequency and a depolarization in the RM following brief hypoxia. The amplitude of the afterhyperpolarization (AHP) was significantly decreased in both type A and type B spontaneous firing MVN neurons. Hypoxia-induced firing response was alleviated by pretreatment with NS1619, a selective BKCa activator. Furthermore, brief hypoxia caused a decrease in the amplitude of iberiotoxin-sensitive outward currents and mRNA level of BKCa in MVN neurons. These results suggest that BKCa channels protect against abnormal MVN neuronal activity induced by hypoxia, and might be a key target for treatment of vertigo and hearing loss in VBI. [ABSTRACT FROM AUTHOR]
Details
- Language :
- English
- ISSN :
- 09374477
- Volume :
- 272
- Issue :
- 10
- Database :
- Academic Search Index
- Journal :
- European Archives of Oto-Rhino-Laryngology
- Publication Type :
- Academic Journal
- Accession number :
- 109077591
- Full Text :
- https://doi.org/10.1007/s00405-014-3158-4