Differential relaxant responses to pinacidil of smooth muscle preparations contracted by a high concentration of potassium in isoosmolar and hyperosmolar solutions.
Pharmacol Toxicol
; 67(3): 252-4, 1990 Sep.
Article
em En
| MEDLINE
| ID: mdl-2255682
ABSTRACT
Contractions were produced in guinea-pig trachealis, aorta and pulmonary artery by depolarization with 124 mM K+ using two commonly applied techniques. Addition of KCl to the organ bath solution making it hyperosmolar induced slowly developing contractions, which were only weakly inhibited by pinacidil. Hyperosmolar mannitol-induced contractions showed similar characteristics. In contrast, contractions elicited by isoosmolar K+ Krebs solution developed more rapidly and could be completely suppressed by pinacidil (10(-6)-10(-3) M) in a concentration-dependent manner. The findings explain previously published discrepant results on the relaxant response to pinacidil of smooth muscle preparations contracted by high concentrations of K+, and indicate other mechanisms of action for pinacidil in addition to K+ channel opening, in the concentration range 10(-6)-10(-3) M.
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Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Vasodilatadores
/
Guanidinas
/
Relaxamento Muscular
/
Músculo Liso
Limite:
Animals
Idioma:
En
Revista:
Pharmacol Toxicol
Assunto da revista:
FARMACOLOGIA
/
TOXICOLOGIA
Ano de publicação:
1990
Tipo de documento:
Article
País de afiliação:
Dinamarca