Coadministration of dextromethorphan during pregnancy and throughout lactation prevents morphine-induced hyperprolactinemia in female rats.
OBJECTIVE
To investigate whether coadministration of dextromethorphan (DM) could suppress morphine-induced hyperprolactinemia in female rats during pregnancy and throughout lactation.


METHODS
Controlled prospective study.


METHODS
University research laboratory.


METHODS
One hundred adult female Sprague-Dawley rats.


METHODS
Rats were randomly divided into four groups and were subcutaneously injected with either saline, morphine, morphine + DM, or DM alone twice a day, progressively increasing by 1 mg/kg at 7-day intervals from an initial dose of 2 mg/kg for both morphine and DM. Drug administration was continued during pregnancy. After the offspring were born, the doses injected into the dams were increased by 1 mg/kg every 2 weeks.


METHODS
Serum prolactin (PRL) concentration and dopamine turnover rate at the hypothalamus and pituitary.


RESULTS
Chronic morphine administration induced higher PRL concentrations than the control animals at mating, and at early and late pregnancy. In rats receiving DM coadministration, we did not observe any increase by morphine. Our neurochemical results showed that this effect of DM may be partly through blocking the effect of morphine on inhibition of tuberoinfundibular dopaminergic (TIDA) neuronal activity.


CONCLUSIONS
The use of DM as an adjuvant in females receiving chronic morphine treatment may prevent morphine-induced hyperprolactinemia.
Wu
Ling-Yi
LY
Graduate Institute of Medical Sciences, National Defense Medical Center, Taipei 114, Taiwan, Republic of China.
Huang
Eagle Yi-Kung
EY
Tao
Pao-Luh
PL