| In Vitro | In vitro activity: At a holding potential of –37 mV, Manidipine decreases the Ca2+ current at concentrations above 0.1 nM, and abolishes it at 100 NM. Manidipine concentration-dependently inhibits the calcium concentration response curves. Manidipine inhibits coronay artery and renal artery with pIC50 of 9.3 nM and 9.1 nM, respectively. Manidipine partly inhibits sympathetic nerve activity and suppresses the mean arterial pressure response to infused norepinephrine. Manidipine also inhibits aldosterone secretion. Manidipine increases in both urinary calcium and uric acid. In addition, Manidipine, at nanomolar concentrations, is efficacious in modulating gene transcriptions that are involved in proinflammatory changes of mesangial cells.
Cell Assay: The mitogenic effect is measured by the amout of [3H]thymidine incorporated into DNA of human MCs and by assessment of cell proliferation. In brief, 1 × 105 quiescent cells is seeded into a 25-mL cell culture bottle and kept in low serum medium (0.1% FCS). On the following day, the cells are preincubated for 3 hours with Manidipine (10 nM) followed by stimulation with PDGF-BB (10 ng/mL) or incubated with low serum medium abone. The medium is replaced each day, and the cells are counted at days 1, 3 and 5.
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| In Vivo | Manidipine (3 mg/kg and 10 mg/kg, p.o.) dose-dependently decreases systolic blood pressure in the three types of hypertensive rats. At the dose of 10 mg/kg, Manidipine decreases the blood pressure to the normotensive level between 1 hour and 3 hours after Manidipine is administered; the antihypertensive effect lasted for at least 8 hours. When Manidipine is administered at 10 μg/kg, the hypotensive action is markedly augmented. Manidipine potently inhibits the Ca inward current, When the potential is at -60 mV. Manidipine consistently inhibits the Ca current evoked by depolarization to 0 mV. However, a low concentration of Manidipine (1-3 nM) enhances the Ca current evoked by the depolarizing pulse of -20 mV, when the membrane potential is held at -80 mV. Inhibition of the Ca current induced by Manidipine develops slowly and over 10 minutes is required to reach the maximum inhibition. |
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