Caliber dependent calcitonin gene-related peptide-induced relaxation in rat coronary arteries: effect of K+ on the tachyphylaxis.
Eur J Pharmacol
; 351(1): 53-9, 1998 Jun 12.
Article
em En
| MEDLINE
| ID: mdl-9698205
ABSTRACT
The influence of vessel caliber on rat calcitonin gene-related peptide (rat-alphaCGRP)-induced responses and the reproducibility of rat-alphaCGRP concentration-response curves were investigated in the left intramural coronary artery of Sprague-Dawley rats. Rat-alphaCGRP (10(-11)-10(-7) M) induced concentration-dependent relaxations with a pD2-value equal to 8.43 +/- 0.05 (n = 44) and maximal relaxation equal to 52 +/- 3% (n = 44). Both the maximal relaxation and the sensitivity to rat-alphaCGRP were significantly and inversely correlated with vessel lumen diameter. The coronary arteries developed tachyphylaxis in response to rat-alphaCGRP, which was concentration dependently decreased by activating the vessels twice with a buffer containing 36 or 125 mM K+. The rat-alphaCGRP-curve became fully reproducible after activation of the arteries twice with 125 mM K+. These results indicate a caliber-related dependency of both the effect of and sensitivity to rat-alphaCGRP in intramural rat coronary arteries because the arteries become more sensitive and reactive to rat-alphaCGRP with decreasing caliber. Tachyphylaxis can be avoided by repeated activation with 125 mM K+.
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Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Potássio
/
Vasodilatação
/
Peptídeo Relacionado com Gene de Calcitonina
/
Vasos Coronários
Limite:
Animals
Idioma:
En
Revista:
Eur J Pharmacol
Ano de publicação:
1998
Tipo de documento:
Article