Cardiovascular effects of the aqueous extract from Caesalpinia ferrea: involvement of ATP-sensitive potassium channels.
Caesalpinia ferrea is a plant very used in the folk medicine for treatment of several diseases, such as diabetes. This study investigated the cardiovascular effects of the aqueous extract from stem bark of C. ferrea (AECF). In non-anesthetized rats, AECF (10, 20, 40, 60 and 80 mg/kg; i.v.) induced hypotension (-9+/-1;-12+/-1;-14+/-1; -20+/-3 and -51+/-6%; respectively) and tachycardia (6+/-1; 8+/-1; 12+/-2; 14+/-2 and 26+/-3%; respectively). Hypotension was not affected after atropine or L-NAME. Furthermore, AECF (40 mg/kg) induced atrioventricular block and extrasystoles, which was not affected after atropine. In intact rings of the rat mesenteric artery, AECF (0.001-30 mg/ml, n=6) induced relaxations of phenylephrine tonus (Emax=110+/-4%), which was not changed after the removal of endothelium (Emax=113+/-9%). In rings without endothelium pre-contracted with KCl 80 mM, phenylephrine plus KCl 20 mM or phenylephrine plus glibenclamide, the curve to AECF was significantly attenuated (Emax=24+/-4%, 70+/-5% and 62+/-7%, respectively, n=6), but was not affected in the presence of tetraethylammonium or 4-aminopyridine (Emax=125+/-15% and 114+/-7%, respectively, n=6). These results demonstrate that AECF induces hypotension associated to tachycardia; however, in dose of 40 mg/kg, AECF induces transient bradyarrhythmias. Furthermore, AECF induces vasodilatation in rat mesenteric artery which appears to be mediated by ATP-sensitive K+ channel openings.
Menezes
Igor A C
IA
Departamento de Fisiologia, Laboratório de Farmacologia Cardiovascular, Universidade Federal de Sergipe, Av. Marechal Rondon, S/N, Rosa Elze, CEP 49100-000, São Cristóvão, SE, Brazil.
Moreira
Italo J A
IJ
Carvalho
Adriana A
AA
Antoniolli
Angelo R
AR
Santos
Márcio R V
MR
D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D029911:Caesalpinia; D004562:Electrocardiography / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D066298:In Vitro Techniques; D008297:Male; D017538:Mesenteric Artery, Superior / Q000187:drug effects / Q000502:physiology; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology; D010936:Plant Extracts / Q000494:pharmacology*; D015221:Potassium Channels / Q000187:drug effects* / Q000502:physiology; D051381:Rats
D010936:Plant Extracts; D015221:Potassium Channels; D001285:Atropine; D000255:Adenosine Triphosphate; D019331:NG-Nitroarginine Methyl Ester