Mechanism of inhibition by hydrogen sulfide of native and recombinant BKCa channels.
Respir Physiol Neurobiol
; 172(3): 169-78, 2010 Jul 31.
Article
em En
| MEDLINE
| ID: mdl-20576528
ABSTRACT
Recent evidence suggests that H(2)S contributes to activation of the carotid body by hypoxia by inhibiting K(+) channels. Here, we determine both the molecular identity of the K(+) channel target within the carotid body and the biophysical characteristics of the H(2)S-evoked inhibition by analyzing native rat and human recombinant BK(Ca) channel activity in voltage-clamped, inside-out membrane patches. Rat glomus cells express the enzymes necessary for the endogenous generation of H(2)S, cystathionine-beta-synthase and cystathionine-gamma-lyase. H(2)S inhibits native carotid body and human recombinant BK(Ca) channels with IC(50) values of around 275 microM. Inhibition by H(2)S is rapid and reversible, works by a mechanism which is distinct from that suggested for CO gas regulation of this channel and does not involve an interaction with either the "Ca bowl" or residues distal to this Ca(2+)-sensing domain. These data show that BK(Ca) is a K(+) channel target of H(2)S, and suggest a mechanism to explain the H(2)S-dependent component of O(2) sensing in the carotid body.
Texto completo:
1
Base de dados:
MEDLINE
Assunto principal:
Bloqueadores dos Canais de Potássio
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Poluentes Atmosféricos
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Canais de Potássio Ativados por Cálcio de Condutância Alta
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Sulfeto de Hidrogênio
Limite:
Animals
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Humans
/
Male
Idioma:
En
Revista:
Respir Physiol Neurobiol
Ano de publicação:
2010
Tipo de documento:
Article
País de afiliação:
Reino Unido