2 RECEPTOR SUBTYPES ARE INVOLVED in the CONTRACTILE COMPONENT of the GUINEA-PIG ILEUM RESPONSES TO ENDOTHELINS

2 RECEPTOR SUBTYPES ARE INVOLVED in the CONTRACTILE COMPONENT of the GUINEA-PIG ILEUM RESPONSES TO ENDOTHELINS

Author Miasiro, N. Autor UNIFESP Google Scholar
Paiva, ACM Autor UNIFESP Google Scholar
Ihara, M. Google Scholar
Yano, M. Google Scholar
Institution BANYU PHARMACEUT CO LTD
Universidade Federal de São Paulo (UNIFESP)
Abstract Endothelin-I (ET-1) and endothelin-3 (ET-3) induced a biphasic response (relaxation and contraction) in the guinea pig ileum. Short-term activation of protein kinase C (PKC) with phorbol 12,13-dibutyrate (PDBu) inhibited the contractile but not the relaxing component of the responses, as did H-7. Long-term pretreatment with PDBu reversed the short-term inhibition but did not affect the tachyphylaxis induced by ET-1. These results suggest that PKC contributes to ET-1 contraction but not to tachyphylaxis. the ETA antagonist BQ- 123, at 34 nM, competitively inhibited ET-1 contraction, but at 340 nM the inhibition was noncompetitive. Dose-response curves for ET-1 relaxation were shifted to the left. for ET-3, BQ-123 (340 nM) only decreased the maximal contractile response of the dose-response curve without affecting the relaxation. We suggest that in this tissue there is one receptor for ET-1-induced contraction, which is competitively antagonized by BQ-123, and another one for ET-3-induced contraction, which is noncompetitively antagonized by BQ-123.
Keywords ENDOTHELIN-1
ENDOTHELIN-3
RECEPTOR SUBTYPES
ENDOTHELIN ANTAGONIST
TACHYPHYLAXIS
Language English
Date 1993-01-01
Published in Journal of Cardiovascular Pharmacology. Philadelphia: Lippincott-raven Publ, v. 22, p. S211-S213, 1993.
ISSN 0160-2446 (Sherpa/Romeo, impact factor)
Publisher Lippincott-raven Publ
Extent S211-S213
Origin http://dx.doi.org/10.1097/00005344-199322008-00057
Access rights Open access Open Access
Type Article
Web of Science ID WOS:A1993MN02800057
URI http://repositorio.unifesp.br/handle/11600/25294

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