CaV 3.1 and CaV 3.3 account for T-type Ca2+ current in GH3 cells
Braz. j. med. biol. res
; 37(6): 929-935, Jun. 2004. ilus, tab, graf
Article
em En
| LILACS
| ID: lil-359901
Biblioteca responsável:
BR1.1
RESUMO
T-type Ca2+ channels are important for cell signaling by a variety of cells. We report here the electrophysiological and molecular characteristics of the whole-cell Ca2+ current in GH3 clonal pituitary cells. The current inactivation at 0 mV was described by a single exponential function with a time constant of 18.32 ñ 1.87 ms (N = 16). The I-V relationship measured with Ca2+ as a charge carrier was shifted to the left when we applied a conditioning pre-pulse of up to -120 mV, indicating that a low voltage-activated current may be present in GH3 cells. Transient currents were first activated at -50 mV and peaked around -20 mV. The half-maximal voltage activation and the slope factors for the two conditions are -35.02 ñ 2.4 and 6.7 ñ 0.3 mV (pre-pulse of -120 mV, N = 15), and -27.0 ñ 0.97 and 7.5 ñ 0.7 mV (pre-pulse of -40 mV, N = 9). The 8-mV shift in the activation mid-point was statistically significant (P < 0.05). The tail currents decayed bi-exponentially suggesting two different T-type Ca2+ channel populations. RT-PCR revealed the presence of a1G (CaV3.1) and a1I (CaV3.3) T-type Ca2+ channel mRNA transcripts.
Texto completo:
1
Índice:
LILACS
Assunto principal:
Hipófise
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Canais de Cálcio Tipo T
Limite:
Humans
Idioma:
En
Revista:
Braz. j. med. biol. res
Assunto da revista:
BIOLOGIA
/
MEDICINA
Ano de publicação:
2004
Tipo de documento:
Article
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Project document