Desmopressin accelerates the rate of urinary morphine excretion and attenuates withdrawal symptoms in rats

The aim of this study was to examine the effects
of desmopressin on morphine withdrawal symptoms
and vasopressin level in morphine-dependent
subjects.
Methods: Wistar male rats were injected s.c. with
morphine once per day for 5 consecutive days to
induce morphine dependence. After morphine use
ceased on day 5, an equal number of rats were
assigned to one of four groups for either saline
or desmopressin by either intraperitoneal (i.p.) or
intracerebroventricular (i.c.v.) injection. From days 5
to 10, urine was collected daily and tested for the
presence of morphine, and withdrawal symptoms
were monitored to assess the effects of desmopressin.
Results: Significant weight loss occurred among all
morphine-addicted rats during the withdrawal
period. With both methods (i.p. and i.c.v.), the
period of urinary morphine excretion was shorter for
the two groups that were given desmopressin (experimental
groups) than the two groups that were not
given desmopressin (control groups), and no significant
difference in urinary morphine excretion was
found between the two experimental groups. During
the early stage of withdrawal, the severity of the withdrawal
symptoms in the experimental groups was
significantly lower than that in the control groups.
Conclusion: Desmopressin decreases the extent of
morphine withdrawal symptoms, indicating that this
agent might be appropriate for treating morphine
addiction. Desmopressin appears to reduce withdrawal
symptoms not by exerting an anti-diuretic
effect but rather by exerting an effect on the central
nervous system