عنوان به زبان ديگر :
Diabetes Increases the Analgesia and Tolerance to Morphine in Acute Pain, but Not in Chronic Pain, While it Attenuates the Dependency in Rats
چكيده لاتين :
Shaheed Beheshti University of Medica l Sciences, Tehran, LR.lran
hanges in the concentration of either C brain or blood glucose level appear to
modulate antinociceptive and basal nociceptive
processes. There are some
contradictory data about the effect of diabetes on
morphine antinociception. In this study the effects
of alloxan-induced diabetes on morphine
analgesia, tolerance and dependency were investigated,
with a view to clarify the contradictions.
Mate rials and Methods: Experimental diabetes
was induced by a single injection of alloxan (120
rug/kg S.c.) in rats. Administration of morphine
sulfate (7m&יkg i.p., 5 days) developed tolerance
in an imals. Acute and chronic pain in morphine
treated diabetic and non-diabetic animals were
eval uated using hot-plate and formalin tests resp
ectively. In tolerant animals withdrawal signs
(jump in g, chewing, urine and feces) were recorded
fo r ten minutes by the use of naloxone
(2m&יkg l.p .).
Res ults: Our results show th at in the acute pain
mode l, the antinociceptive effect of a morphine
single dose was signifi cantly enhanced (P <
0.001) in the diabetic gr oup as compared to nondiabetic
ra ts whereas, in dia beti c tolerant rats in
comparison with th e non-diabetic tolerant ones
Conclusion: It appears that the effects of hyperglycemia
on pain thresholds differ in specific regions,
using different tests and by duration of
diabetes. Thus during the progress of diabetes,
hyperglycemia might diminish the analgesic effect
of morphine, blunt the development of dependency
and alter the induction of tolerance.
