四氢小檗碱对离体兔主动脉环的作用和离体豚鼠结肠带平滑肌~(45)Ca内流的影响

THB和Ver相似,对KCl和NE所致兔主动脉环收缩,呈非竞争性拮抗,THB的作用弱于Ver。THB对KCl所致的兔主动脉环收缩的松弛作用,能被20 mmol/L CaCl_2所对抗。 THB,THP和Ver明显抑制80 mmol/L KCl所致的豚鼠结肠带平滑肌细胞的~(43)Ca内流。THB的作用与THP相当,但均弱于Ver。

Effects of tetrahydroberberine on isolated rabbit aortic rings and on ~(45)Ca influx in isolated guinea pig taenia coli smooth muscle

The effects of tetrahydroberberine(THB)on the isolated rabbit aortic rings were studied in comparison with verapamil(Ver).THB relaxed 60 mmol/L potassium-depolarization evoked contraction in the isolated rabbit aorta rings but the relaxation was antagonised by 20 mmol/L CaCl2.Similar to Ver,THB shifted KC1 and norepinephrine(NE)dose-response curve to the right in a nonparallel fashion,and decreased maximal response,showing noncompetitive antagonism.PD'2 values of THB were 3.3 and 2.6,respectively.The effect of THB was less in potency as compared with Ver.Both THB and Ver markedly inhibited 80 mmol/L KCl-stimulated 45Ca influx in the guineapig taenia coli smooth muscle.The rate of inhibition of 80 mmol/L KCl-stimulated 9 min 45Ca influx by Ver(10μmol/L)was 40 %.The rate of inhibition of high KC1 stimulated 45Ca influx by THB(10μmol/L and 100μmol/L)were 16 %(p<0.01)and 27 %(p<0.01),respectively.The rate of inhibition of THP(10μmol/L and 100μmol/L)were 15 %(p<0.01)and 24 %(p<0.01),respectively.They all had no effect on the resting 45Ca influx.