Treatment with a Ca²⁺ channel blocker, barnidipine, reduces platelet-derived growth factor B-chain mRNA in glomeruli of spontaneously hypertensive rats

We investigated the effect of barnidipine hydrochloride, a Ca²⁺ channel blocker, on the glomerular level of mRNA expression of platelet-derived growth factor (PDGF) B-chain and transforming growth factor (TGF)-β₁ in spontaneously hypertensive rats (SHR) with reverse transcription and polymerase chain reaction. Thirteen-week-old SHR were provided with food containing barnidipine (0.6 mg/g of food, average dose during treatment: 53 mg/kg of body mass/day) for 3 weeks. A stable reduction in systolic blood pressure relative to that of age-matched control SHR was recorded after week 1 of therapy. Although no renal histological changes were observed after 3 weeks of treatment with barnidipine, the level of expression of PDGF B-chain mRNA in glomeruli was significantly reduced relative to that in control SHR. The glomerular level of TGF-β₁ mRNA expression was not affected by the treatment. Treatment with barnidipine significantly reduced the excretion of urinary protein. Thus, the stable reduction in systemic blood pressure by barnidipine is associated with a reduction in PDGF B-chain mRNA expression in the glomerulus and reduction in urinary protein excretion in SHR.