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

Marine Drugs

Thyago M. Queiroz²  Natália T. Machado²  Fabíola F. Furtado²  Abrahão A. Oliveira-Filho²  Maria C. Alustau²  Camila S. Figueiredo²  George E. C. Miranda²  José M. Barbosa-Filho²  Valdir A. Braga¹ 

[1] Biotechnology Center, Federal University of Paraiba, João Pessoa, PB 58.051-900, Brazil;

关键词: calcium;    hypotension;    mesenteric artery;    vasodilatation;   

DOI  :  10.3390/md9102075

来源: mdpi

【 摘 要 】

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; −8 ± 2; −53 ± 8 and −63 ± 3 mmHg) and bradycardia (−8 ± 6; −17 ± 11; −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.

【 授权许可】

CC BY   
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