Administration of barnidipine (1-10 microg/kg iv) caused dose-dependent dilation of afferent and efferent arterioles in normal, hypertensive, and diabetic rats.
A novel videomicroscope system demonstrated that the calcium channel antagonist barnidipine differentially affects afferent and efferent arteriolar diameters depending on the underlying pathology (hypertension vs. diabetes) in rat models.
We developed a videomicroscope system with a charge-coupled device camera and evaluated it in the investigation of the glomerular microcirculation in normal Wistar-Kyoto (WKY), spontaneously hypertensive (SHR), and streptoyotocin-induced diabetic rats (STZ). In WKY, the diameter of the afferent arterioles (Af) was 11.9 +/- 0.7 microm and that of the efferent arterioles (Ef) was 8.9 +/- 0.7 microm. Af and Ef in each glomerulus could be visualized simultaneously with continuous recording of blood pressure and renal blood flow. In SHR, Af diameter was constricted to approximately 60% of that in WKY. A dose-dependent dilation of Af and Ef was observed after administration of barnidipine (1-10 microg/kg iv), a calcium channel antagonist, in all three groups. No change was seen in the Af-to-Ef diameter ratio (Af/Ef ratio) in WKY. In SHR, the Af/Ef ratio increased significantly because of the marked dilation of Af after barnidipine administration. In contrast, barnidipine dilated Ef in STZ, causing a significant reduction in the Af/Ef ratio. This system can analyze in vivo glomerular microcirculation and systemic macrocirculation simultaneously, allowing more direct investigation of the characteristics of and acute changes in glomerular microcirculation in pathological animals.
Yamamoto et al. (Sat,) conducted a other in Hypertension and diabetes (animal model). Barnidipine vs. Baseline / Normal rats was evaluated on Afferent and efferent arteriole diameter changes. Administration of barnidipine (1-10 microg/kg iv) caused dose-dependent dilation of afferent and efferent arterioles in normal, hypertensive, and diabetic rats.