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Vasorelaxation, Induced by Dictyota pulchella (Dictyotaceae), a Brown Alga, Is Mediated via Inhibition of Calcium Influx in Rats

Authors :
Thyago M. Queiroz
Abrahão Alves de Oliveira-Filho
Camila S. Figueiredo
José Maria Barbosa-Filho
Valdir A. Braga
Maria C. Alustau
Natália T. Machado
George Emmanuel Cavalcanti de Miranda
Isac Almeida de Medeiros
Fabíola Fialho Furtado
Source :
Marine Drugs, Vol 9, Iss 10, Pp 2075-2088 (2011), Marine Drugs, Volume 9, Issue 10, Pages 2075-2088
Publication Year :
2011
Publisher :
MDPI AG, 2011.

Abstract

This study aimed to investigate the cardiovascular effects elicited by Dictyota pulchella, a brown alga, using in vivo and in vitro approaches. In normotensive conscious rats, CH2Cl2/MeOH Extract (CME, 5, 10, 20 and 40 mg/kg) from Dictyota pulchella produced dose-dependent hypotension (−4 ± 1<br />−8 ± 2<br />−53 ± 8 and −63 ± 3 mmHg) and bradycardia (−8 ± 6<br />−17 ± 11<br />−257 ± 36 and −285 ± 27 b.p.m.). In addition, CME and Hexane/EtOAc Phase (HEP) (0.01–300 µg/mL) from Dictyota pulchella induced a concentration-dependent relaxation in phenylephrine (Phe, 1 µM)-pre-contracted mesenteric artery rings. The vasorelaxant effect was not modified by the removal of the vascular endothelium or pre-incubation with KCl (20 mM), tetraethylammonium (TEA, 3 mM) or tromboxane A2 agonist U-46619 (100 nM). Furthermore, CME and HEP reversed CaCl2-induced vascular contractions. These results suggest that both CME and HEP act on the voltage-operated calcium channel in order to produce vasorelaxation. In addition, CME induced vasodilatation after the vessels have been pre-contracted with L-type Ca2+ channel agonist (Bay K 8644, 200 nM). Taken together, our data show that CME induces hypotension and bradycardia in vivo and that both CME and HEP induce endothelium-independent vasodilatation in vitro that seems to involve the inhibition of the Ca2+ influx through blockade of voltage-operated calcium channels.

Details

Language :
English
ISSN :
16603397
Volume :
9
Issue :
10
Database :
OpenAIRE
Journal :
Marine Drugs
Accession number :
edsair.doi.dedup.....bffabd240614ed82f44c26efa59b076d