N. Suzuki et al., INTRATHECAL MORPHINE-3-GLUCURONIDE DOES NOT ANTAGONIZE SPINAL ANTINOCICEPTION BY MORPHINE-6-GLUCURONIDE IN RATS, European journal of pharmacology, 249(2), 1993, pp. 247-250
Morphine or morphine-6-glucuronide either alone or in combination with
morphine-3-glucuronide was administered intrathecally to rats. Antino
ciceptive effects were evaluated with the tail flick and the hot plate
tests. Motor function was tested using the rotarod test. Estimated ED
(50) from the dose-response curves for morphine and morphine-6-glucuro
nide showed about a 30 times more potent antinociceptive effect of mor
phine-6-glucuronide compared with morphine. Morphine-3-glucuronide had
no antinociceptive effect. Simultaneous administration of morphine-3-
glucuronide 5.0 mu g did not show any significant effect on antinocice
ption induced by morphine 1.0 mu g or morphine-6-glucuronide 0.05 mu g
.