Survey on the interaction effect of dopamine D2 receptor antagonist on morphine-induced polycystic ovary syndrome in rat

Polycystic ovary syndrome (PCOS) is one of the most common endocrine and metabolic disorders in premenopausal women. Opioid drugs, including morphine are effective inducers of the PCOS. Hyperprolactinemia also increases the likelihood of this complication. The dopamine, the inhibitor of prolactin secretion, has receptors in the ovarian tissue. In this study, metoclopramide was used as a dopamine receptor antagonist (D2) to survey the interaction of dopamine with morphine.

48 female Wistar rats were studied as virgins (and under the diestrus phase) in the weight range of 220-250 g. The first group received morphine (5 mg/kg) intraperitoneally. The second to fourth groups received metoclopramide (1, 2, 4 mg/kg). In groups 5 to 7, the antagonist (1, 2, 4 mg/kg) with morphine (5 mg/kg) was injected over a period of 20 minutes. The control group received only saline (1 ml/kg). Forty-eight hours after drug administration, the animals underwent surgery and the ovaries and uterus were examined. Statistical analysis was performed by analysis of variance.

The ovaries showed a polycystic view in the morphine group. There were no cystic structures in the metoclopramide groups, but the number of ovarian cysts increased in the metoclopramide+morphine recipient groups. There was a relative increase in uterine diameter due to morphine injection which returned in combination with the antagonist.

Metoclopramide may have increased morphine-induced cystogenesis in the ovary by inhibiting dopamine receptors and increasing the prolactin effect.