Abstract
Female Wistar rats were injected subcutaneously with 1mg/kg reserpine on the day of diestrus-I to induce pseudopregnancy. Three days later, the reserpine-treated rats were adiministered additionally with nialamide (250mg/kg, monoamine oxidase inhibitor), L-DOPA (250mg/kg) or ergot alkaloids (1mg/kg, ex., ergocornine & ergocryptine). At the same time, one of the uterine horns was traumatized to examine deciduoma formation.
Treatment with nialamide or L-DOPA was not effective to interrupt reserpine-induced pseudopregnancy. Deciduoma formation occurred in all rats receiving nialamide or L-DOPA 3 days after reserpinization. However, no deciduoma response was obtained in the rats treated with ergocornine or ergocryptine on the same day. Inhibitory effect of ergocornine on deciduoma formation failed to reverse by simultaneous injection of phentolamine (α-receptor blocker) or propranolol (β-receptor blocker) with ergocornine. On the contrary, when pimozide and ergocornine were given together to the reserpine-treated rats, the effect of ergocornine was found to be inhibited. All rats treated with pimozide concurrently with ergocornine or ergocryptine had deciduoma in their traumatized uterine horn. Since pimozide was regarded as a blocker of dopamine receptor, the interruption of pseudopregnancy induced by ergocornine or ergocryptine was considered to be correlated with the dopaminergic mechanism.
