Cardiac Protective Effects Research Articles

The Effect of Amlodipine on Hypertension-Induced Cardiac Hypertrophy and Reperfusion-Induced Calcium Overload

Amlodipine is a long-acting dihydropyridine-based calcium antagonist developed for use on a once-a-day basis. Experiments were undertaken to establish whether the chronic administration of amlodipine prevents the rise in blood pressure in spontaneously hypertensive rats (SHR), and whether it attenuates cardiac hypertrophy caused by hypertension. The experiments were performed in spontaneously hypertensive rats, and normotensive Wistar-Kyoto (WKY) and Sprague-Dawley (SD) rats. Amlodipine was given orally to provide a daily intake of 10 mg kg-1 day-1. The rats were 8 weeks old at the start of the therapy. In the SHR, but not in the WKY or SD rats, the blood pressure was reduced (p less than 0.01) after 30 weeks in the rats receiving amlodipine but not in the placebo-treated rats. At the same time the heart-to-body-weight ratio was reduced in the amlodipine-treated SHR but not in the SD or WKY rats. This same amlodipine regimen (10 mg kg-1 day-1 orally) or amlodipine i.v. (0.25 mg/kg, 5 h before excising the hearts) improved functional recovery (p less than 0.01) of hearts "stunned" by 10 min ischemia and attenuated (p less than 0.05) calcium ion gain on reperfusion after 30 to 60 min ischemia. These results indicate that prophylactic therapy with amlodipine lowers blood pressure in hypertensive rats, prevents hypertension-induced hypertrophy, and exerts a cardiac-protective effect during short periods of ischemia.

Renin Profiling to Select Anti hypertensive Baseline Drugs: Renin Inhibitors for High-Benin and Calcium Entry Blockers for Low-Benin Patients

Renin profiling stimulated research into the pathophysiology of essential hypertension and influenced the development of antihypertensive treatment strategies. Patients with a high renin value and usually younger age respond better to drugs that interfere with the renin-angiotensin system, that is, beta blockers or converting enzyme inhibitors. Patients with a low renin value and often older age respond better to calcium entry blockers or diuretics. Patients with normal renin levels exhibit mixed but, on average, equal responses to these types of drugs. A pathophysiology-oriented antihypertensive treatment strategy is proposed in which beta blockers or converting enzyme inhibitors are used as one and calcium entry blockers--in the place of diuretics when possible--as the other baseline drug, and this approach may provide a cardiac-protective effect.