铅对幼年大鼠钙的吸收和骨骼生长的影响

目的研究铅对大鼠钙的吸收和骨骼生长的影响。方法分别以纯净水和1.0g/L醋酸铅水饲喂Wistar大鼠,其中醋酸铅饲喂大鼠又分别以正常饲料、高钙饲料和低钙饲料饲养,对应分组为对照组、单铅染毒组、高钙铅染毒组和低钙铅染毒组。观察大鼠生长发育,测定大鼠血清中骨钙素和甲状旁腺激素的含量,检测骨骼中铅和钙的含量,石蜡切片HE染色比较大鼠股骨显微结构变化。另饲养10只Wistar大鼠,以45CaCl2示踪研究铅对钙吸收的影响。结果铅和低钙处理明显抑制大鼠生长发育,使大鼠股骨的长度和直径减小,且低钙加剧了铅对骨骼的抑制作用,而高钙则拮抗铅对骨骼的抑制作用。示踪结果显示铅可显著抑制大鼠体内钙的吸收。结论铅可能通过抑制大鼠体内钙的吸收而使骨骼生长受限,补充适量钙有助于减轻铅对骨骼生长的抑制。

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 BERBAMINE ON CONTRACTION AND Ca2＋INFLUX OF ISOLATED BASILAR ARTERY AND THORACIC AORTA IN RABBITS

Effects of berbamine on contraction and Ca2+ infux of isolated basilar artery or thoracicaorta in rabbits were observed in vitro,by comparing its action with those of the calcium entryblocker,ailtiazem.The results showed that berbamine relaxed markedly high k+-induced contractionof basilar artery and its action was antagonized by increasing the coneentratind of extracelular Ca2+Berbamine can noncompetitively antagonize basilar artery or thoracic aorta coatractious evoked byCaCl2 and serotonin, and the action on basilar artery was more effective than that on thoracic aorta.It inhibited the 45 Ca2+ infux caused by noradrenaline and high k+ in thoracic aorta with a concentration-dependeat manner. The action of berbamine was the same as that of diltiazem.With or withoutvascular endothelium of thoracic aorta,the pD'2 values of berbamine antagonizing KCl dose-responsecurves were 4.29±0.10 and 4.30±0.09 (P>0.05)respectively.These results indicate that Ca2+antagonistic action of berbamine is an endothelium-independent.