The effects of quercetin, flavone, catechin and chrysin on the naloxone-pre
cipitated withdrawal contracture of the acute morphine-dependent guinea-pig
ileum have been investigated in-vitro.
After 4 min in-vitro exposure to morphine a strong contracture of guinea-pi
g isolated ileum was observed after the addition of naloxone. All the flavo
noids, injected 10min before morphine at concentrations between 10(-7) and
10(-5) M, Were capable of blocking naloxone-induced contracture after expos
ure to morphine in a concentration-dependent fashion. IC50 values calculate
d for quercetin, flavone, catechin and chrysin were 2.7 x 10(-6), 7.3 x 10(
-7), 8.5 x 10(-7) and 5.3 x 10(-6) M, respectively.
These results suggest that flavonoids might play an important role in the c
ontrol of morphine withdrawal.