In vivo visualization of characteristics of renal microcirculation in hypertensive and diabetic rats.
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
T
T
Department of Urology, Kawasaki Medical School, 577 Matsushima, Kurashiki, Okayama 701-0192, Japan.
Tomura
Y
Y
Tanaka
H
H
Kajiya
F
F
D000818:Animals; D001160:Arterioles / Q000473:pathology / Q000502:physiology / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects / Q000502:physiology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D003921:Diabetes Mellitus, Experimental / Q000473:pathology / Q000503:physiopathology*; D006439:Hemodynamics / Q000187:drug effects / Q000502:physiology; D006973:Hypertension / Q000235:genetics / Q000503:physiopathology*; D007678:Kidney Glomerulus / Q000098:blood supply; D008297:Male; D008833:Microcirculation / Q000473:pathology / Q000502:physiology / Q000503:physiopathology*; D009543:Nifedipine / Q000031:analogs & derivatives / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D014661:Vasoconstriction; D014664:Vasodilation
D002121:Calcium Channel Blockers; C050699:mepirodipine; D009543:Nifedipine