A study of glaucine-induced relaxation of rat aorta.
The vasorelaxant effect of glaucine, the major alkaloid of Platycapnos spicata (L.) Bernh., was studied. At concentrations of 10 microM-0.3 mM in normal Krebs solution it was almost equieffective in relaxing K(+)-induced and noradrenaline-induced tension in rat aortic rings without endothelium, with IC50 values of 160 +/- 16 microM and 90 +/- 14 microM respectively. In experiments in a calcium-free medium, 10 microM glaucine strongly inhibited noradrenaline-induced contractions. Glaucine (0.3 mM) did not affect basal uptake of 45Ca, but induced uptake was reduced to 100% (K+) and 97.7% (noradrenaline) of the basal value. These results suggest that glaucine has an intracellular effect and also acts on the cell membrane by blocking voltage-dependent and receptor-operated calcium channels.
Loza
I
I
Departamento de Farmacología, Farmacia y Tecnología Farmaceutica, Facultad de Farmacia, Universidad de Santiago, Santiago de Compostela, Spain.
Orallo
F
F
Verde
I
I
Gil-Longo
J
J
Cadavid
I
I
Calleja
J M
JM
D000818:Animals; D001011:Aorta / Q000187:drug effects*; D001060:Aporphines / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000187:drug effects*; D010944:Plants / Q000737:chemistry; D051381:Rats; D017207:Rats, Sprague-Dawley
D001060:Aporphines; C005004:glaucine; D002118:Calcium