Blockade of the bradykinin-evoked diphasic response of isolated rat duodenum by the crude extract of and compounds obtained from Mandevilla velutina.
The influence of an aqueous/ethanolic extract of M. velutina (CE) and of two compounds (MV 8608 and MV 8612) purified from the plant on BK-, Ad- and K+-induced responses of the rat duodenum was analyzed in vitro. In preparations precontracted with Ca2+, the CE (1 and 2 mg/ml) markedly inhibited BK-induced relaxation in a dose-dependent manner but was less effective against Ad-induced relaxation. The CE (0.5 mg/ml) also antagonized BK-induced relaxation and contraction of strips bathed in normal medium. The two compounds from M. velutina (10 and 20 micrograms/ml) also promoted a dose-dependent blockade of both responses to BK, only slightly depressing the response to K+.
Calixto
J B
JB
Departamento de Farmacologia, Universidade Federal de Santa Catarina, Florianópolis, Brasil.
Strobel
G H
GH
Cruz
A B
AB
Yunes
R A
RA
D000818:Animals; D001920:Bradykinin / Q000037:antagonists & inhibitors*; D001938:Brazil; D004386:Duodenum / Q000187:drug effects*; D004837:Epinephrine / Q000037:antagonists & inhibitors; D005260:Female; D008297:Male; D009119:Muscle Contraction / Q000187:drug effects*; D009126:Muscle Relaxation / Q000187:drug effects*; D010936:Plant Extracts / Q000494:pharmacology*; D010946:Plants, Medicinal; D011188:Potassium / Q000037:antagonists & inhibitors; D051381:Rats
D010936:Plant Extracts; D011188:Potassium; D001920:Bradykinin; D004837:Epinephrine