Abstract
Chronic use of glyceryl trinitrate is limited by serious side effects,
inter alia tolerance and endothelial dysfunction of coronary and
resistance arteries. The natural flavonoid quercetin has been shown to
counteract the development of glyceryl trinitrate tolerance in vitro.
Two mitochondriotropic, 4-O-triphenylphosphoniumbutyl derivatives of
quercetin (QTA-3BTPI and Q-3BTPI) were compared to quercetin for protection
against glyceryl trinitrate-induced tolerance and endothelial dysfunction of
isolated rat aorta rings. Both QTA-3BTPI and Q-3BTPI significantly
counteracted the reduced vascular responsiveness to both glyceryl trinitrate
and acetylcholine caused by prolonged exposure of the vessel to glyceryl
trinitrate itself, their potency being much greater than that of quercetin.
QTA-3BTPI, however, turned out to cause endothelial dysfunction per
se. Since Q-3BTPI antagonized in vitro nitrate tolerance and
endothelial dysfunction of vessels, this encourages assessing whether this
effect is displayed also in vivo during long-term glyceryl trinitrate
treatment.
Key words
rat aorta rings - glyceryl trinitrate tolerance - endothelial dysfunction - quercetin