[Antihypertrophic effect of dihydropyridines calcium channel blockers is dependent on their potential of blocking N-type calcium channel].
OBJECTIVE
To compare the effects of amlodipine, benidipine and nifedipine on myocardial hypertrophy and evaluate the underlying mechanism.


METHODS
Myocardial hypertrophy model was created by transverse aortic constriction (TAC) in C57 BL/6 mice, and plasma catecholamine concentrations were measured 7 days after surgery to confirm the sympathetic activation. The 3 drugs were administered in TAC mice for 7 days and cardiac hypertrophy was evaluated according to the heart-to-body weight ratio (HW/BW). Effects of those drugs on the protein synthesis stimulated by phenylephrine in cultured neonatal cardiac myocytes were also examined.


RESULTS
HW/BW and plasma concentrations of catecholamine were significantly increased in TAC mice one week after surgery in comparison with to sham-operated mice. One week after TAC, the HW/BW ratio was significantly lower in the amolodipine but not nifedipine-treated group than in the TAC group. Administration of nifedipine via minipump infusion for one week did not decrease HW/BW ratio. Treatment with amlodpine or benidipine, but not nifedipine, decreased the neonatal rat myocyte protein synthesis induced by phenylephrine stimulation.


CONCLUSIONS
Antihypertrophic effect of DHEs on myocardium is dependent on their potential of blocking N-type calcium channel, and the underlying mechanism involves the sympathetic inhibition.
Luo
Qiong
Q
Department of Pathophysiology, School of Basic Medical Sciences, Southern Medical University, Guangzhou 510515, China.
Xuan
Wan-ling
WL
Xi
Fang
F
Liao
Yu-lin
YL
Kitakaze
Masafumi
M
D017311:Amlodipine / Q000494:pharmacology / Q000627:therapeutic use; D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology* / Q000627:therapeutic use; D020864:Calcium Channels, N-Type / Q000187:drug effects*; D006332:Cardiomegaly / Q000188:drug therapy* / Q000209:etiology; D004095:Dihydropyridines / Q000494:pharmacology* / Q000627:therapeutic use; D004195:Disease Models, Animal; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009543:Nifedipine / Q000494:pharmacology / Q000627:therapeutic use
D002121:Calcium Channel Blockers; D020864:Calcium Channels, N-Type; D004095:Dihydropyridines; D017311:Amlodipine; C061004:benidipine; D009543:Nifedipine