effect of sulpiride on dopaminergic synapse of dorsal hippocampus of morphine-treated rats

Background: as previous studies show, several effects of morphine are induced by the dopaminergicsystem. sulpiride is a dopamine d2 receptor (dad2) antagonist widely used in clinics to treat darelateddisorders. dad2 receptors are abundant at hippocampal cornu ammonis (ca1).objectives: this study aimed to investigate the possible interaction of morphine and sulpiride onda synapses in ca1.materials & methods: in this study, 48 wistar rats weighing 220 to 250 g were used. these animalswere classified into eight groups (6 rats per group): saline control group (1 ml/kg), morphinegroup (5 mg/kg), sulpiride groups alone (1, 2, and 4 mg/kg) and sulpiride groups (1, 2, and 4 mg/kg)+morphine (5 mg/kg). saline or substances were injected once intraperitoneally. after 48 h, theanimals’ brains were removed under anesthesia and placed in 10% formalin for fixation. then, 3- to4-μm slices were cut from these tissues, and the da synapse was examined by histochemistry andimmunohistochemistry techniques. the data were statistically analyzed by the analysis of variance.results: the control group had da synapses and healthy neurons. a relative increase in dasynapses compared to the control group was observed in the morphine and single sulpiride groups.however, in sulpiride+morphine groups, da synapses were reduced compared to morphine orsulpiride alone, but neurons were not destroyed.conclusion: the interaction effect of sulpiride and morphine in the ca1 region may decrease dasynapses.