Lysophosphatidyl choline modulates mechanosensitive L-type Ca2+ current in circular smooth muscle cells from human jejunum.
Am J Physiol Gastrointest Liver Physiol
; 296(4): G833-9, 2009 Apr.
Article
em En
| MEDLINE
| ID: mdl-19179622
ABSTRACT
The L-type Ca2+ channel expressed in gastrointestinal smooth muscle is mechanosensitive. Direct membrane stretch and shear stress result in increased Ca2+ entry into the cell. The mechanism for mechanosensitivity is not known, and mechanosensitivity is not dependent on an intact cytoskeleton. The aim of this study was to determine whether L-type Ca2+ channel mechanosensitivity is dependent on tension in the lipid bilayer in human jejunal circular layer myocytes. Whole cell currents were recorded in the amphotericin-perforated-patch configuration, and lysophosphatidyl choline (LPC), lysophosphatidic acid (LPA), and choline were used to alter differentially the tension in the lipid bilayer. Shear stress (perfusion at 10 ml/min) was used to mechanostimulate L-type Ca2+ channels. The increase in L-type Ca2+ current induced by shear stress was greater in the presence of LPC (large head-to-tail proportions), but not LPA or choline, than in the control perfusion. The increased peak Ca2+ current also did not return to baseline levels as in control conditions. Furthermore, steady-state inactivation kinetics were altered in the presence of LPC, leading to a change in window current. These findings suggest that changes in tension in the plasmalemmal membrane can be transmitted to the mechanosensitive L-type Ca2+ channel, leading to altered activity and Ca2+ entry in the human jejunal circular layer myocyte.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Lisofosfatidilcolinas
/
Canais de Cálcio Tipo L
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Miócitos de Músculo Liso
/
Jejuno
Tipo de estudo:
Prognostic_studies
Limite:
Humans
Idioma:
En
Revista:
Am J Physiol Gastrointest Liver Physiol
Ano de publicação:
2009
Tipo de documento:
Article