Vasodilator effects of Diocleinae lectins from the Canavalia genus.
This study investigated and compared vascular actions of leguminous lectins obtained from the Canavalia genus (Canavalia brasiliensis, Canavalia gladiata, and Canavalia maritima) in the rat models of paw edema and isolated aorta. Paw edema was induced by subcutaneous injection of lectins (0.01-1 mg/kg) in animals pre-treated or not with indomethacin or L-NAME. In isolated aorta, cumulative concentration curves of C. gladiata or C. brasiliensis (1-100 microg/ml) were performed at the contraction plateau induced by phenylephrine or at tissue basal tonus. The mechanism of the lectin relaxant action was investigated by previous addition of L-NAME, indomethacin, or tetraethylammonium. In both models, the lectin domain involvement was evaluated by incubation of lectins with their ligand and non-ligand sugars. The lectins induced paw edema paralleled by protein leakage. The edematogenic activity elicited by C. gladiata and C. brasiliensis involves prostaglandins and nitric oxide (NO), while that of C. maritima occurs without NO interference. C. gladiata and C. brasiliensis elicited aorta relaxation involving NO and prostacyclin, while that of C. gladiata included EDHF. All lectin effects were prevented by their binding sugars. The present study demonstrated important vasodilator effects of different degrees and mechanisms in vivo and in vitro of Canavalia lectins. In vivo, the edematogenic activity was paralleled by plasma exudation, and in vitro, aorta relaxation was strictly dependent on intact endothelium. All effects occurred via interaction with lectin domains and participation of NO and/or prostanoids.
Instituto Superior de Ciências Biomédicas, Universidade Estadual do Ceará, Av. Paranjana 1700, Fortaleza, Ceará, Brazil. assreuy@uece.br
Ana Maria Sampaio
AM
Assreuy
Sabrina Rodrigues
SR
Fontenele
Alana de Freitas
Ade F
Pires
Débora Costa
DC
Fernandes
Natália Velloso Fontenelle C
NV
Rodrigues
Eduardo Henrique Salviano
EH
Bezerra
Tales Rocha
TR
Moura
Kyria Santiago
KS
do Nascimento
Benildo Sousa
BS
Cavada
D000818:Animals; D001013:Aorta, Thoracic / Q000187:drug effects / Q000378:metabolism; D032449:Canavalia / Q000737:chemistry*; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D004487:Edema / Q000139:chemically induced / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009569:Nitric Oxide / Q000378:metabolism; D037121:Plant Lectins / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*; D011453:Prostaglandins / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D014664:Vasodilation / Q000187:drug effects*; D014665:Vasodilator Agents / Q000008:administration & dosage / Q000302:isolation & purification / Q000494:pharmacology*
D037121:Plant Lectins; D011453:Prostaglandins; D014665:Vasodilator Agents; D009569:Nitric Oxide