[Effects of calcium antagonists on withdrawal of beta-receptor blockers in rats during left ventricular hypertrophy].
The hemodynamic changes of metoprolol (Met, 50 mg.kg-1.d-1, po, 3 wk) withdrawal for 1 day and the effects of nifedipine (Nif) and m-nifedipine (m-Nif) on these changes were observed in pressure overload hypertrophy in rats by abdominal aortic constriction for 4 wk. Both Nif and m-Nif (10 mg.kg-1.d-1, respectively, po, 3 wk) significantly attenuated the increase of MAP (from 14.3 +/- 2.3 to 12.9 +/- 2.3 and 11.3 +/- 2.4 kPa, respectively, n = 6-7, P < 0.05) and decrease the abnormal development of systolic function of left ventricle after Met withdrawal. Radioreceptor assay indicates that Nif and m-Nif can prevent the up-regulation of myocardium beta-receptors in left ventricular hypertrophy and large dose of Met exposure for a long time. These results suggest that calcium antagonists administered with beta-blockers can prevent beta-receptor blocker withdrawal syndrome.
Li
Q P
QP
Department of Cardiovascular Pharmacology, Nanjing Medical University.
Rao
M R
MR
D000818:Animals; D006439:Hemodynamics / Q000187:drug effects; D017379:Hypertrophy, Left Ventricular / Q000188:drug therapy*; D007536:Isomerism; D008297:Male; D008790:Metoprolol / Q000009:adverse effects* / Q000627:therapeutic use; D009206:Myocardium / Q000378:metabolism; D009543:Nifedipine / Q000494:pharmacology / Q000627:therapeutic use*; D051381:Rats; D017207:Rats, Sprague-Dawley; D011943:Receptors, Adrenergic, beta / Q000378:metabolism; D013375:Substance Withdrawal Syndrome / Q000378:metabolism / Q000503:physiopathology / Q000517:prevention & control*
D011943:Receptors, Adrenergic, beta; D008790:Metoprolol; D009543:Nifedipine