Effect of nifedipine on capacitive calcium entry in Jurkat T lymphocytes.
Arch Biochem Biophys
; 481(1): 80-5, 2009 Jan 01.
Article
em En
| MEDLINE
| ID: mdl-18950601
ABSTRACT
The effect of nifedipine-an antagonist of L-type calcium (Ca(2+)) channels-on capacitative Ca(2+) entry (CCE) was studied in Jurkat T lymphocytes. CCE was induced by a variety of treatments each of which depleted intracellular Ca(2+) stores. Cells were treated with thapsigargin, ionomycin, anti-CD3 antibodies, and phytohaemagglutinin, or pre-incubated in a Ca(2+)-free medium. Activity of CCE was evaluated with a Ca(2+)-free/Ca(2+)-readmission protocol, in Fluo-3 pre-loaded cells. Nifedipine inhibited CCE in a dose-dependent manner. CCE inhibition was not due to non-specific effects on K(+) channels. Nifedipine, did not induce any membrane depolarization, as revealed by measurements of the plasma membrane potential with the fluorescent probe bis-oxonol. Moreover, experiments done under depolarizing conditions (i.e. by substituting Na(+) with K(+) ions in the medium) revealed that nifedipine could inhibit capacitative Ca(2+) entry independently of plasma membrane depolarization. We also demonstrated the presence in our Jurkat T-cells of transcripts for Ca(V)1.3 (alpha(1D)) and Ca(V)1.4 (alpha(1F)) L-type Ca(2+) channels. Verapamil and diltiazem, two unrelated blockers of L-type Ca(2+) channels, were less inhibitory on CCE. Possible mechanisms by which nifedipine interferes with Ca(2+) entry in these cells are discussed.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Bloqueadores dos Canais de Cálcio
/
Nifedipino
/
Cálcio
Tipo de estudo:
Guideline
Limite:
Humans
Idioma:
En
Revista:
Arch Biochem Biophys
Ano de publicação:
2009
Tipo de documento:
Article
País de afiliação:
Itália