Authors:
Adilbay Esimbetov, Abdisalim Zaripov,Sirojiddin. Omonturdiev
, Mukhlis Sultankhodjaev
and Pulat Usmanov ,Uzbekistan |
Abstract:
To investigate the possible mechanisms of vasorelaxant action of 1-O-benzoylnappeline (1-0-
BN), a diterpenoid alkaloid napelline derivative.: The vasorelaxant activity of 1-0-BN was
examined using standard organ bath techniques and endothelium intact rat aortic rings,
precontracted by phenylephrine (PE) or by a high KCl (50 mM). 1-O-BN induced
vasorelaxation, in rat aortic rings, precontracted by both PE and high KCl, in a concentrationdependent manner and with almost equal effectiveness. 1-O-BN significantly attenuated CaCl2-
induced contractions in a Ca2 +-free medium containing KCl (50 mM). Furthermore, the
vasorelaxant potency of 1-O-BN significantly reduced in the presence of verapamil. 1-O-BN
significantly reduced the transient contractions induced by PE or caffeine in Ca2+-free medium.
The vasorelaxant effect of 1-O-BN progressively reduced with an elevation of KCl concentration
(from 20 mM to 100 mM) and markedly attenuated by glibenclamide but not significantly
affected by TEA, BaCl2, and 4-AP. Together, the results of the present study indicate that
activation of KATP channels may play an important role in 1-O-BN induced vasorelaxation. The
suppression of contractions induced by high KCl and by PE, in calcium-free medium, suggest
that the inhibition of Ca2+ influx through voltage-dependent Ca2+ channels and Ca2+ release
from intracellular stores also may be involved in the vasorelaxant effect of 1-O-BN |
