Cardiovascular effects of Sida cordifolia leaves extract in rats.
The cardiovascular activity of the aqueous fraction of the hydroalcoholic extract of Sida cordifolia leaves (AFSC) was evaluated. In normotensive non-anaesthetized rats was observed that AFSC (5, 10, 20, 30 and 40 mg/kg, i.v.) induced hypotension (6 +/- 2%; 8 +/- 2%; 11 +/- 2%; 19 +/- 3% and 33 +/- 3%, respectively) and bradycardia (0.3 +/- 3%; 13 +/- 4%; 38 +/- 6%; 64 +/- 7% and 80 +/- 5%, respectively). Hypotensive response was completely abolished after atropine (2 mg/kg; i.v.) but potentialized after hexamethonium (20 mg/kg; i.v.) (12 +/- 2%; 21 +/- 5%; 28 +/- 3%; 32 +/- 2% and 32 +/- 3%, respectively), while bradycardic response was completely abolished after atropine (2 mg/kg; i.v.) and attenuated with hexamethonium (20 mg/kg; i.v.) (1 +/- 0.3%; 5 +/- 1%; 7 +/- 1%; 7 +/- 1% and 10 +/- 1%, respectively). In hexamethonium treated rats, L-NAME significantly attenuated the hypotensive response (9 +/- 2%; 14 +/- 1%; 16 +/- 1%; 16 +/- 2% and 22 +/- 3%, respectively). In normotensive anaesthetized and vagotomized rats, hypotensive and bradycardic responses were significantly attenuated (0.5 +/- 0.2%; 1 +/- 0.4%; 3 +/- 0.6%; 4 +/- 0.8% and 6 +/- 1%, respectively, n = 6, and 7 +/- 2%; 12 +/- 5%; 15 +/- 2%, 17 +/- 2% and 25 +/- 3%, respectively). The anaesthesia with sodium thiopental did not affect the AFSC-induced responses when compared with those induced in non-anaesthetized rats (data not showed). In conclusion, the results obtained so far show that AFSC produce hypotension and bradycardia, mainly due to a direct stimulation of the endothelial vascular muscarinic receptor and indirect cardiac muscarinic activation, respectively.
Medeiros
I A
IA
Laboratório de Tecnologia Farmacêutica, Universidade Federal da Paraiba, João Pessoa, PB, Brazil. isacmed@uol.com.br
Santos
M R V
MR
Nascimento
N M S
NM
Duarte
J C
JC
D000758:Anesthesia; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D001919:Bradycardia / Q000139:chemically induced; D002319:Cardiovascular System / Q000187:drug effects*; D004562:Electrocardiography / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects*; D008297:Male; D019660:Malvaceae / Q000737:chemistry*; D010936:Plant Extracts / Q000494:pharmacology*; D018515:Plant Leaves / Q000737:chemistry*; D051381:Rats; D017208:Rats, Wistar; D014628:Vagotomy
D010936:Plant Extracts