Characterization of single L-type Ca2+ channels in myocytes isolated from the cricket lateral oviduct.
J Comp Physiol B
; 175(4): 257-63, 2005 May.
Article
en En
| MEDLINE
| ID: mdl-15900506
ABSTRACT
The single Ca2+ channel activity was obtained from cell-attached patch recordings with the use of pipettes filled with 100 mM Ba2+ as the charge carrier in myocytes isolated from the lateral oviduct of cricket Gryllus bimaculatus. The following results were obtained. (1) The channel had a unitary conductance of 18 pS. (2) The open time histogram of the channel could be fitted with a single exponential while the closed time histogram could be fitted with the sum of two exponentials, suggesting that there are at least one open state and two closed states for this channel. (3) The open probability of the channel increased with increasing membrane depolarization. (4) The mean current reconstructed by averaging individual current trace responses inactivated slowly and the current-voltage relationship for the peak mean current showed a bell-shaped relation. (5) The dihydropyridine (DHP) Ca2+ antagonist, nifedipine, reduced the mean current by increasing the proportion of "blank" sweeps. On the other hand, the DHP Ca2+ agonist, Bay K 8644, increased the mean current by increasing the mean open-times of the channel. These results confirm a presence of DHP-sensitive L-type Ca2+ channel in myocytes isolated from the lateral oviduct of cricket G. bimaculatus.
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Colección:
01-internacional
Base de datos:
MEDLINE
Asunto principal:
Oviductos
/
Agonistas de los Canales de Calcio
/
Bloqueadores de los Canales de Calcio
/
Ácido 3-piridinacarboxílico, 1,4-dihidro-2,6-dimetil-5-nitro-4-(2-(trifluorometil)fenil)-, Éster Metílico
/
Nifedipino
/
Canales de Calcio Tipo L
/
Células Musculares
Límite:
Animals
Idioma:
En
Revista:
J Comp Physiol B
Asunto de la revista:
BIOQUIMICA
/
FISIOLOGIA
/
METABOLISMO
Año:
2005
Tipo del documento:
Article
País de afiliación:
Japón