Involvement of Na+-Ca2+ exchanger in cAMP-mediated relaxation in mice aorta: evaluation using transgenic mice.
Br J Pharmacol
; 150(4): 434-44, 2007 Feb.
Article
em En
| MEDLINE
| ID: mdl-17220909
ABSTRACT
BACKGROUND AND PURPOSE:
Although vascular smooth muscle cells are known to express the Na+-Ca2+ exchanger (NCX), its functional role has remained unclear, mainly because of its relatively low expression. We thus investigated the involvement of NCX in the mechanism for the forskolin-induced vaso-relaxation, using wild type (WT) and transgenic (TG) mice that specifically over-express NCX1.3 in smooth muscle. EXPERIMENTALAPPROACH:
We examined the relaxing effect of forskolin during the pre-contraction induced by 100 nM U46619, a thromboxane A2 analogue in the mouse isolated thoracic aorta. We also measured the intracellular Ca2+ concentration ([Ca2+]i) in fura-PE3-loaded aortic strips. KEYRESULTS:
The forskolin-induced decreases in [Ca2+]i and tension were much greater in aortas from TG mice than in those from WT mice. In a low Na+ solution, forskolin-induced decreases in [Ca2+]i and tension were greatly inhibited in both groups of aortas. In WT aortas, the presence of 100 nM SEA0400, an NCX inhibitor, had only a little effect on the forskolin-induced decreases in [Ca2+]i, but inhibited the forskolin-induced relaxation. However, in TG aortas, the presence of SEA0400 greatly inhibited the forskolin-induced decreases in [Ca2+]i and tension. CONCLUSIONS AND IMPLICATIONS The NCX was involved in the forskolin-induced reduction of [Ca2+]i and tension in the mouse thoracic aorta. Measurement of [Ca2+]i and tension in aortas of the TG mouse is thus considered to be a useful tool for evaluating the role of NCX in vascular tissue.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
AMP Cíclico
/
Trocador de Sódio e Cálcio
/
Músculo Liso Vascular
Limite:
Animals
Idioma:
En
Ano de publicação:
2007
Tipo de documento:
Article