INHIBITORY EFFECTS OF NIFEDIPINE ON DNA AND PROTEIN-SYNTHESIS IN CULTURED CARDIAC NONMYOCYTES OF NEONATAL RATS

AIM: To observe the inhibitory effects of nifedipine (Nif) on cardiac nonmyocytes growth and proliferation. METHODS: Using nonmyocytes in cu lture as a model, [H-3]thymidine and [H-3]leucine incorporation were m easured. RESULTS: There was a significant decrease in cell number and in total cellular protein after 72-h exposure to Nif 1 mu mol . L(-1) in the presence of angiotensin II (Ang II). A 48-h exposure to 1, 10, 100, 1000 nmol . L(-1) of Ang II caused a 19 %, 35 %, 46 %, 48 % incre ase in protein synthesis and 27 %, 46 %, 56 %, 57 % increase in DNA sy nthesis. Nif 1, 3, and 10 mu mol . L(-1) were able to reduce the Ang I I 100 nmol . L(-1)-induced increase of protein synthesis and DNA synth esis. CONCLUSION: Nif had a direct inhibitory action on the growth of nonmyocytes, which was related to the regression of cardical hypertrop hy.