Effects of barnidipine hydrochloride, a calcium channel blocker, on renal microcirculation in rats: A pilot study

Barnidipine hydrochloride, a dihydropyridine calcium channel blocker, incre ases both renal blood flow and glomerular filtration while effectively redu cing blood pressure. The goal of the present study was to determine the eff ects of barnidipine on renal microcirculation, We used the rat in vivo spli t hydronephrotic kidney model to directly observe renal arterioles by light microscopy, When administered into the organ bath (ie, administered from o utside of the blood vessels), 10(-7) RI of barnidipine significantly dilate d both afferent and efferent arterioles and increased glomerular blood flow in both normotensive and hypertensive rats. Systolic blood pressure remain ed unchanged. Intravenous injection of barnidipine 600 mu g/kg body weight dilated afferent arterioles and increased glomerular blood flow in normoten sive rats, In contrast, the same treatment in hypertensive rats caused sign ificant sustained dilatation of both afferent and efferent arterioles and g radually reduced systolic blood pressure. Future studies are needed to dete rmine the clinical relevance of these effects of barnidipine.