Effect of Alisma plantago-aquatica Linn extract on hyperprolactinemia in rats

Purpose: To investigate the anti-hyperprolactinemia effect and mechanism of action of of Alisma plantago-aquatica Linn. extract (APLE) in rats. Methods: The hyperprolactinemia (hyperPRL) model of rats was established by intraperitoneal (i.p.) metoclopramide (200 mg/kg daily) for 10 days. Sixty rats were divided into six groups (n = 10 each): normal group), hyperPRL control group, hyperPRL plus 0.6 mg/kg bromocriptine (as a positive control) group, and hyperPRL plus high (14.4 g/kg), medium (7.2 g/kg), or low (3.6 g/kg) dose of APLE. Bromocriptine or vehicle control was administered to the rats daily for 30 days, and the hypothalamus dopamine D2 receptor, protein kinase A (PKA), and cyclic adenosine monophosphate (cAMP) levels were investigated by Western blot. Results: Compared with the normal rats, hypothalamus dopamine D2 receptor protein expression was significantly lower in hyperPRL rats (p < 0.01), but was changed significantly after 30-day doses (various) of APLE administration (3.6 g/kg, p < 0.05; 7.2 and 14.4 g/kg, p < 0.01). Compared with the control rats, hypothalamus PKA and cAMP levels were significantly higher in hyperPRL rats (p < 0.01). These increases in PKA and cAMP were significantly attenuated by 30-day of bromocriptine treatment or various doses of APLE (p < 0.01). Conclusion: The anti-hyperPRL activity of APLE is confirmed from the findings of this study Thus, the plant can potentially be developed into a new anti-hyperprolactinemia drug.