Effects of acetazolamide on transient K+ currents and action potentials in nodose ganglion neurons of adult rats.
CNS Neurosci Ther
; 17(1): 66-79, 2011 Feb.
Article
em En
| MEDLINE
| ID: mdl-20370806
ABSTRACT
The aim of the present study was to determine whether acetazolamide (AZ) contributes to the inhibition of the fast inactivating transient K(+) current (I(A) ) in adult rat nodose ganglion (NG) neurons. We have previously shown that pretreatment with either AZ or 4-AP attenuated or blocked the CO(2) -induced inhibition of slowly adapting pulmonary stretch receptors in in vivo experiments. The patch-clamp experiments were performed by using the isolated NG neurons. In addition to this, the RT-PCR of mRNA and the expression of voltage-gated K(+) (Kv) 1.4, Kv 4.1, Kv 4.2, and Kv 4.3 channel proteins from nodose ganglia were examined. We used NG neurons sensitive to the 1 mM AZ application. The application of 1 mM AZ inhibited the I(A) by approximately 27% and the additional application of 4-AP (1 mM) further inhibited I(A) by 48%. The application of 0.1 µM α-dendrotoxin (α-DTX), a slow inactivating transient K(+) current (I(D) ) blocker, inhibited the baseline I(A) by approximately 27%, and the additional application of 1 mM AZ further decreased the I(A) by 51%. In current clamp experiments, AZ application (1 mM) increased the number of action potentials due to the decreased duration of the depolarizing phase of action potentials and/or due to a reduction in the resting membrane potential. Four voltage-gated K(+) channel proteins were present, and most (80-90%) of the four Kv channels immunoreactive neurons showed the co-expression of carbonic anhydrase-II (CA-II) immunoreactivity. These results indicate that the application of AZ causes the reduction in I(A) via the inhibition of four voltage-gated K(+) channel (Kv) proteins without affecting I(D).
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potenciais de Ação
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Canais de Potássio de Abertura Dependente da Tensão da Membrana
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Bloqueadores dos Canais de Potássio
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Acetazolamida
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Neurônios
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Gânglio Nodoso
Limite:
Animals
Idioma:
En
Revista:
CNS Neurosci Ther
Ano de publicação:
2011
Tipo de documento:
Article