The effect of angiotensin II on the number of macula densa cells through the AT1 receptor.
The present study was performed to obtain information about a possible correlation between the activity of the renin-angiotensin system and the stereological features of the macula densa (MD). In normal kidneys, the numbers of angiotensin II AT1 receptors were estimated in MD cells and in the neighboring tubular cells. The total volumes of MD, MD cells, neighboring tubular cells, and the total number of MD cells, were measured in normal and candesartan-treated rats (15 mg/kg/day over 21 days). In the normal kidneys, the relative number of AT1 receptors in MD cells [mean = 0.17 (CV = 0.23)] was significantly (p = 0.03) lower than that in normal tubular cells [0.25 (0.21)]. A significant difference (p < 0.01) was observed in the total volume between MD cells [515 microm(3) (0.14)] and normal tubular cells [984 microm(3) (0.19)]. Candesartan treatment significantly elevated (p < 0.01) the total volume of the MD, whereas the total number of MD cells was increased [from 14.2 (0.11) to 19.5 (0.11)]. The results demonstrated that the transdifferentiation from normal tubular cells to MD cells can be controlled by pharmacological means. The structural features of MD controlled by the renin-angiotensin system may be one of the important factors governing the sensitivity of tubuloglomerular feedback.
Razga
Zsolt
Z
Department of Pathology, University of Szeged, Szeged, Hungary. razgazst@patho.szote.u-szeged.hu
Nyengaard
Jens Randel
JR
D000804:Angiotensin II / Q000378:metabolism*; D047228:Angiotensin II Type 1 Receptor Blockers / Q000494:pharmacology; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D001713:Biphenyl Compounds; D002452:Cell Count; D049109:Cell Proliferation / Q000187:drug effects; D054338:Cell Transdifferentiation / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D007606:Juxtaglomerular Apparatus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1 / Q000187:drug effects / Q000378:metabolism*; D013777:Tetrazoles / Q000494:pharmacology
D047228:Angiotensin II Type 1 Receptor Blockers; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D044140:Receptor, Angiotensin, Type 1; D013777:Tetrazoles; D000804:Angiotensin II; C081643:candesartan