Effects Of Amino Acids On Spontaneous Contraction Of Pregnant Mice Myometrium

Uterus irregular contraction is the most obvious sign of premature birth, and generally occurs in the early and mid-and late pregnancy, uterine smooth muscle keeping a relative quiescent state is essential for pregnancy maintenance. Studies have shown that some amino acids have effects on contraction of uterine smooth muscle.The effects of nine kinds of amino acids on concentration gradient (1,5,10mmol·L-1) of the non-pregnant mice uterine smooth muscle spontaneous contraction were measured by RM6240BD multi-channel physiological signal acquisition system, to find the type of amino acids that have effect of inhibit uterine smooth muscle contraction. The inhibite rate of His on concentration gradient is29.0%,78.0%,100%respectively; the inhibite rate of Arg is3.8%,32.6%,35.1%respectively. The inhibite rate range of Cys, Gln, Ile, Phe and Met on concentration gradient is-9.3%^-91.6%,-7.0%⁴4.0%,-1.0%^-107.4%,-2.8%^-27.7%and9.3%^-100.1%. The inhibite rates of Leu and Lys are lower than20%. The results show that Arg and His have significant inhibitation on the contraction of non-pregnant mouse uterine smooth muscle; Cys, Gln, Ile, Phe and Met can promote contraction; the effects of Leu and Lys are not obvious.In this thesis, further research about the effects of Arg and His in the gradient of the concentration of0.1,0.5,1,2,5and10mmol·L-1, on15.5dpc (days post coitum),17.5dpc and18.5dpc pregnant mice uterine smooth muscle spontaneous contraction were mearured. The inhibite rates of Arg to three periods of pregnant mice uterine smooth muscle contraction of the concentration gradients are (27.6±6.3)%^100.0±0%,(31.3±15.6)%-(52.4±17.7)%and (32.2±14.4)%^69.4±9.3%; inhibite rates of His are (34.0±5.3)%^100.0±0%,(21.1±2.8)%^100.0±0%and (26.5±11.5)%^100.0±0%.The Arg and His can completely inhibite the spontaneous contraction of15.5dpc pregnant mice uterine smooth muscle when the concentration reaches5mmol·L-1. His of10mmol·L-1can completely inhibite the spontaneous contraction of15.5dpc,17.5dpc and18.5dpc pregnant mice uterine smooth muscle.10mmol·L-1Arg can only inhibite the spontaneous contraction of15.5dpc pregnant mice uterine smooth muscle. The Results indicate that Arg and His have obvious inhibition to three periods of pregnant mice uterine smooth muscle contraction of the concentration gradients, and the same concentration of amino acids on the three periods of pregnant mice uterine contraction have different inhibit efficiency.In this thesis, the content of free Arg and His in pregnant mice (15.5dpc and18.5dpc) serum are measured by LC-MS/MS. In15.5dpc pregnant mice serum, the content of free Arg and His is (325.69±41.79)μmol·L-1,(139.70±67.07) μmol·L-1respectively; in18.5dpc pregnant mice serum, the content of free Arg and His is (182.08±6.53)μmol·L-(117.4±24.53) μmol·L-1respectively. The results show that the contents of Arg and His in the two periods of pregnant mice serum are different. The concentration of Arg and His in15.5dpc pregnant mice serum is high, which may enhance the inhibition of the pregnant mice uterine smooth muscle spontaneous contraction; and the concentration of Arg and His in18.5dpc pregnant mice serum is low, which may be benefit for the promotion of the parturition start. These two amino acids may be used as the drugs to prevent preterm birth at midanaphase to maintain gestation, and can provide expermental and theoretical basis for the development of new anti-perterm labor medicines.