| Registro completo |
| Provedor de dados: |
BJMBR
|
| País: |
Brazil
|
| Título: |
Inhibition of PKC-dependent extracellular Ca2+ entry contributes to the depression of contractile activity in long-term pressure-overloaded endothelium-denuded rat aortas
|
| Autores: |
Padilla,J.
López,R.M.
López,P.
Castillo,M.C.
Querejeta,E.
Ruiz,A.
Castillo,E.F.
|
| Data: |
2014-09-01
|
| Ano: |
2014
|
| Palavras-chave: |
Long-term pressure overload
Rat aorta
Protein kinase C
|
| Resumo: |
We examined the contractile responsiveness of rat thoracic aortas under pressure overload after long-term suprarenal abdominal aortic coarctation (lt-Srac). Endothelium-dependent angiotensin II (ANG II) type 2 receptor (AT2R)-mediated depression of contractions to ANG II has been reported in short-term (1 week) pressure-overloaded rat aortas. Contractility was evaluated in the aortic rings of rats subjected to lt-Srac or sham surgery (Sham) for 8 weeks. ANG I and II levels and AT2R protein expression in the aortas of lt-Srac and Sham rats were also evaluated. lt-Srac attenuated the contractions of ANG II and phenylephrine in the aortas in an endothelium-independent manner. However, lt-Srac did not influence the transient contractions induced in endothelium-denuded aortic rings by ANG II, phenylephrine, or caffeine in Ca2+-free medium or the subsequent tonic constrictions induced by the addition of Ca2+ in the absence of agonists. Thus, the contractions induced by Ca2+ release from intracellular stores and Ca2+ influx through stored-operated channels were not inhibited in the aortas of lt-Srac rats. Potassium-elicited contractions in endothelium-denuded aortic rings of lt-Srac rats remained unaltered compared with control tissues. Consequently, the contractile depression observed in aortic tissues of lt-Srac rats cannot be explained by direct inhibition of voltage-operated Ca2+ channels. Interestingly, 12-O-tetradecanoylphorbol-13-acetate-induced contractions in endothelium-denuded aortic rings of lt-Srac rats were depressed in the presence but not in the absence of extracellular Ca2+. Neither levels of angiotensins nor of AT2R were modified in the aortas after lt-Srac. The results suggest that, in rat thoracic aortas, lt-Srac selectively inhibited protein kinase C-mediated activation of contraction that is dependent on extracellular Ca2+ entry.
|
| Tipo: |
Info:eu-repo/semantics/article
|
| Idioma: |
Inglês
|
| Identificador: |
http://www.scielo.br/scielo.php?script=sci_arttext&pid=S0100-879X2014000900789
|
| Editor: |
Associação Brasileira de Divulgação Científica
|
| Relação: |
10.1590/1414-431X20143073
|
| Formato: |
text/html
|
| Fonte: |
Brazilian Journal of Medical and Biological Research v.47 n.9 2014
|
| Direitos: |
info:eu-repo/semantics/openAccess
|
