プロスタグランジン F_2α 誘発子宮平滑筋収縮に対する乳清ミネラルの抑制作用およびその抑制機序について

抄録

 Alamin 996 is a mixture of mineral contained in the milk whey and has been reported to be effective against dysmenorrhea This study aimed to investigate the effect of Alamin 996 on the prostaglandin F_2α (PGF_2α)-induced contraction in the isolated rat uterus. PGF_2α induced the rhythmic contraction. The frequency of this contraction was concentration-dependently inhibited by Alamin 996, but the contractile force was not significantly affected. To clarify this inhibitory mechanism by Alamin996, the effects of BAY K 8644, Ca²⁺ channel agonist, and dantrolene, inhibitor of the calcium-induced calcium release from the endoplasmic reticulum, were tested. The inhibitory effect on the rhythmic contractile frequency by Alamin 996 was significantly and concentration-dependently attenuated by the addition of BAY K 8644, suggesting Alamin 996 did not affect on the smooth muscle contractile function. Even under the pretreatment with dantrolene, Alamin 996 concentration-dependently inhibited the rhythmic contractile frequency, suggesting no involvement of ryanodine receptor on the effect of Alamin 996. Alamin 996 was found to inhibit phospholipase C activity by in vitro study. The effect of Mg²⁺ containing Alamin 996 was tested. Mg²⁺ significantly and concentration-dependently inhibited the frequency of PGF_2α-induced rhythmic contraction. Moreover, contractile force was also markedly inhibited, suggesting the difference of the inhibitory mechanism between Alamin 996 and Mg²⁺ sulfate. These results show that Alamin 996 inhibits the PGF_2α-induced rhythmic contractile frequency without affecting the contractile force and that this inhibitory action mediated by inhibiting calcium release from the endoplasmic reticulum through phospholipase C may explain the utility of Alamin 996 against dysmenorrhea.