Visualization of renal microcirculation in isolated Munich-Wistar rat kidneys: effects of endothelin-1 on renal hemodynamic activity.
The aim of the present study was to visualize the superficial glomeruli of the Munich-Wistar (MW) rat and to characterize the responses of the renal microvasculature to endothelin-1 (ET-1). We first examined the distribution of superficial glomeruli of the MW rat compared to that in a control strain (Wistar rat). Secondly, we examined the effects of ET-1 on the renal microcirculation of the MW rat. The right kidney was perfused with a Krebs-Ringer solution containing fluorescein isothiocyanate dextran (FITC-dextran) and was visualized under an epi-illuminated fluorescence microscope system. Changes in perfusion pressure and diameter of the microvessels accompanying the administration of ET-1 (10 fmole-300 pmole) were measured. The number of superficial glomeruli was greater in the MW rat than in the Wistar rat. ET-1 had long-lasting and dose-dependent pressor effects. Perfusion pressure showed a 3.5-fold increase compared with the control, and the afferent arterioles showed greater dose-dependent vasoconstriction than the efferent arterioles. These findings suggest that the MW rat is a useful animal model for the study of renal microcirculation and that the renal microcirculation is extremely sensitive to ET-1.
Saito
M
M
Tsukuba Research Laboratories, Eisai Co., Ltd., Ibaraki, Japan.
Homma
S
S
Yamatsu
I
I
Sato
M
M
Ohshima
N
N
D000704:Analysis of Variance; D000818:Animals; D003911:Dextrans / Q000008:administration & dosage; D004305:Dose-Response Relationship, Drug; D016232:Endothelins / Q000494:pharmacology* / Q000502:physiology; D016650:Fluorescein-5-isothiocyanate / Q000008:administration & dosage / Q000031:analogs & derivatives; D006439:Hemodynamics / Q000187:drug effects*; D066298:In Vitro Techniques; D007678:Kidney Glomerulus / Q000098:blood supply / Q000187:drug effects* / Q000648:ultrastructure; D008297:Male; D008833:Microcirculation / Q000187:drug effects; D008856:Microscopy, Fluorescence; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D012079:Renal Circulation / Q000187:drug effects*
D003911:Dextrans; D016232:Endothelins; C015219:fluorescein isothiocyanate dextran; D016650:Fluorescein-5-isothiocyanate