Document Detail


Warifteine, a bisbenzylisoquinoline alkaloid, induces relaxation by activating potassium channels in vascular myocytes.
MedLine Citation:
PMID:  23140478     Owner:  NLM     Status:  Publisher    
Abstract/OtherAbstract:
This study employed functional and electrophysiological approaches to investigate the mechanisms by which warifteine, a bisbenzylisoquinoline alkaloid isolated from Cissampelos sympodialis Eichl, causes vasorelaxation in the rat thoracic aorta. Warifteine (1 pM-10 μM) induced a concentration-dependent relaxation (pD(2) =9.40±0.06, n=5) in endothelium-intact aortic rings pre-contracted with noradrenaline (10 - 100 μM). The relaxation effects were not attenuated after endothelium removal. Warifteine also induced relaxations (pD(2) =9.2±0.19,n=8) in rings pre-contracted with PGF2(alfa) (1 - 10 mM). In contrast, the relaxant activity of warifteine was nearly abolished in high-K(+) (80 mM) pre-contracted aortic rings. In preparations incubated with 20 mM KCl or K(+) channel blockers, including: TEA (1, 3 and 5 mM), iberiotoxin (20 nM), 4-aminopyridine (1 mM) or glibenclamide (10 μM), the vasorelaxant activity of warifteine was markedly reduced. Furthermore, BaCl(2) (1 mM) did not affect the relaxant effects of warifteine. In vascular myocytes, warifteine (100 nM) significantly increased whole-cell K(+) currents (at 70 mV). In nominally Ca(2+) -free conditions, warifteine did not reduce extracellular Ca(2+) -induced contractions in high-K(+) or noradrenaline (100 μM) pre-stimulated rings. 4. Taken together, these results indicate that warifteine can induce potent concentration-dependent relaxation in the rat aorta via an endothelium-independent mechanism that involves the activation of K(+) channels. © 2012 The Authors Clinical and Experimental Pharmacology and Physiology © 2012 Wiley Publishing Asia Pty Ltd.
Authors:
Apio Cláudio de Lima Assis; Islania Giselia Albuquerque Araújo; Renata Pereira Costa de Lima; Mônica Moura de Almeida; Alexsandro Fernandes Marinho; José Maria Barbosa-Filho; Jader Santos Cruz; Darizy Flávia Silva; Isac Almeida Medeiros
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Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2012-11-12
Journal Detail:
Title:  Clinical and experimental pharmacology & physiology     Volume:  -     ISSN:  1440-1681     ISO Abbreviation:  Clin. Exp. Pharmacol. Physiol.     Publication Date:  2012 Nov 
Date Detail:
Created Date:  2012-11-12     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  0425076     Medline TA:  Clin Exp Pharmacol Physiol     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
Copyright Information:
© 2012 The Authors Clinical and Experimental Pharmacology and Physiology © 2012 Wiley Publishing Asia Pty Ltd.
Affiliation:
Laboratório de Tecnologia Farmacêutica, Universidade Federal da Paraíba - UFPB, João Pessoa, PB, Brazil.
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