title: Calcium influx inhibition is involved in the hypotensive and vasorelaxant effects induced by yangambin.
abstract: The pharmacological effects on the cardiovascular system of yangambin, a lignan isolated from Ocotea duckei Vattimo (Lauraceae), were studied in rats using combined functional and biochemical approaches. In non-anaesthetized rats, yangambin (1, 5, 10, 20, 30 mg/kg, i.v.) induced hypotension (-3.5 ± 0.2; -7.1 ± 0.8; -8.9 ± 1.3; -14 ± 2.3, -25.5% ± 2.6%, respectively) accompanied by tachycardia (5.9 ± 0.5; 5.9 ± 1.6; 8.8 ± 1.4; 11.6, 18.8% ± 3.4%, respectively). In isolated rat atria, yangambin (0.1 µM-1 mM) had very slight negative inotropic (Emax = 35.6% ± 6.4%) and chronotropic effects (Emax = 10.2% ± 2.9%). In endothelium-intact rat mesenteric artery, yangambin (0.1 µM-1 mM) induced concentration-dependent relaxation (pD2 = 4.5 ± 0.06) of contractions induced by phenylephrine and this effect was not affected by removal of the endothelium. Interestingly, like nifedipine, the relaxant effect induced by yangambin was more potent on the contractile response induced by KCl 80 mM (pD2 = 4.8 ± 0.05) when compared to that induced by phenylephrine. Furthermore, yangambin inhibited CaCl2-induced contractions in a concentration-dependent manner. This lignan also induced relaxation (pD2 = 4.0 ± 0.04) of isolated arteries pre-contracted with S(-)-Bay K 8644. In fura-2/AM-loaded myocytes of rat mesenteric arteries, yangambin inhibited the Ca2+ signal evoked by KCl 60 mM. In conclusion, these results suggest that the hypotensive effect of yangambin is probably due to a peripheral vasodilatation that involves, at least, the inhibition the Ca2+ influx through voltage-gated Ca2+ channels.
authors.affiliation: Laboratório de Farmacologia Cardiovascular, Centro de Biotecnologia, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil.
authors.forename: Islania Giselia Albuquerque
authors.initials: IG
authors.lastname: Araújo
authors.affiliation: Laboratório de Neurociências, Instituto de Ciências da Saúde, Universidade Federal da Bahia, Avenida Reitor Miguel Calmon, Vale do Canela, 40110-902 Salvador, BA, Brazil.
authors.forename: Darizy Flávia
authors.initials: DF
authors.lastname: Silva
authors.affiliation: Laboratório de Farmacologia Cardiovascular, Centro de Biotecnologia, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil.
authors.forename: Maria
authors.initials: M
authors.lastname: do Carmo de Alustau
authors.affiliation: Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil.
authors.forename: Katy Lísias Gondim
authors.initials: KL
authors.lastname: Dias
authors.affiliation: Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil.
authors.forename: Karla Veruska Marques
authors.initials: KV
authors.lastname: Cavalcante
authors.affiliation: Laboratório de Farmacologia Cardiovascular, Centro de Biotecnologia, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil.
authors.forename: Robson Cavalcante
authors.initials: RC
authors.lastname: Veras
authors.affiliation: Laboratório de Farmacologia Cardiovascular, Centro de Biotecnologia, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil.
authors.forename: José Maria
authors.initials: JM
authors.lastname: Barbosa-Filho
authors.affiliation: Departamento de Farmacologia, Escola de Medicina de Ribeirão Preto, Universidade de São Paulo, postal code Ribeirão Preto, SP, Brazil.
authors.forename: Mario Dos Anjos
authors.initials: Mdos A
authors.lastname: Neto
authors.affiliation: Departamento de Farmacologia, Escola de Medicina de Ribeirão Preto, Universidade de São Paulo, postal code Ribeirão Preto, SP, Brazil.
authors.forename: Lusiane Maria
authors.initials: LM
authors.lastname: Bendhack
authors.affiliation: Departamento de Fisiologia e Patologia, Centro de Ciências da Saúde, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil.
authors.forename: Nadja
authors.initials: N
authors.lastname: de Azevedo Correia
authors.affiliation: Laboratório de Farmacologia Cardiovascular, Centro de Biotecnologia, Universidade Federal da Paraíba, Cidade Universitária, 58051-900 João Pessoa, PB, Brazil. isacmed@uol.com.br.
authors.forename: Isac
authors.initials: I
authors.lastname: Almeida de Medeiros
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002118:Calcium / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects; D005663:Furans / Q000494:pharmacology*; D006325:Heart Atria / Q000187:drug effects; D007022:Hypotension / Q000139:chemically induced*; D066298:In Vitro Techniques; D017705:Lignans / Q000494:pharmacology*; D008297:Male; D017538:Mesenteric Artery, Superior / Q000187:drug effects; D009131:Muscle, Smooth, Vascular / Q000187:drug effects; D010656:Phenylephrine / Q000494:pharmacology; D011189:Potassium Chloride / Q000494:pharmacology; D017208:Rats, Wistar; D013610:Tachycardia / Q000139:chemically induced; D014665:Vasodilator Agents / Q000494:pharmacology*
chemical_list: D005663:Furans; D017705:Lignans; D014665:Vasodilator Agents; D010656:Phenylephrine; C082827:epiyangambin; D011189:Potassium Chloride; D002118:Calcium