甲氧乙心安及吲哚洛尔对大鼠心肌及尿中去甲肾上腺素和肾上腺素含量的影响

给大鼠连续7d(dl—d7)sc吲哚洛尔200μg/kg·d或甲氧乙心安12.5mg/kg·d,用荧光分光法测心肌及尿中NA及A的含量。在d2及d6吲哚洛尔分别使心肌中NA降到正常值的69％及19％(p<0.01),A的变化相仿。尿中NA在d2亦降低。停药后尿中NA反而比正常增多(p<0.001)。甲氧乙心安在d2使心肌中NA降低(p<0.01),d6时增多(p<0.01)。d2尿中NA增多,但停药后未见反跳现象。讨论了吲哚洛尔与甲氧乙心安对组胺中NA影响的差别,与吲哚洛尔的内在活性及甲氧乙心安的β_1选择性的关系。

Influence of metoprolol and pindolol on cardiac and urinary noradrenaline and adrenaline level in rats

The cardiac and urinary NA and A were assayed fluo-rometrically in rats, which were administered with pindolol 0.2 mg /kg or metoprolol 12.5mg/kg sc for 7 days(d1 -d 7 ). On the d 2 and d 6 of continuous medication of pindolol, there was a marked decrease in cardiac NA down to 69% and 19% of control (p<0.01), respectively, and changes in cardiac A were similar. The urinary level of NA also reduced on d 2 of injection. Afterwithdrawal of pindolol a rebound of urinary NA was noticed(p<0.01). On the d 2 of continuous sc injection of metoprolol, reduction in cardiac NA was significant,however, it went up and reached the level higher than control (p<0.01) on the d 6. The urinary NA content increased on d 2 of medication. No rebound of NA was observed after cessation of metoprolol. The difference between effects of pindolol and metoprolol on the cardiac and uri-naryNA may be related to the partial agonist activity of pindolol and β1-cardioselectivity of metoprolol.