Effects of anesthesia on plasma and kidney ANG II levels in normotensive and ANG II-dependent hypertensive rats.
BACKGROUND
Previous studies have implicated that normotensive rats with normal renal renin activity respond to anesthesia and surgery with greater increases in plasma and kidney angiotensin II (ANG II) concentrations than ANG II-dependent hypertensive rats with intrarenal renin depletion. In the present study, we therefore compared plasma and kidney ANG II levels in anesthetized and conscious normotensive and ANG II-dependent hypertensive rats.


METHODS
Salt-replete Hannover-Sprague-Dawley rats (HanSD) served as controls. As models of ANG II-dependent hypertension we used: 1st, transgenic rats harboring the Ren-2 renin gene (TGR); 2nd, two-kidney, one-clip (2K1C) Goldblatt hypertensive rats, and, 3rd, ANG II-infused hypertensive rats. As additional model with enhanced renin-angiotensin system (RAS) activity, salt-depleted HanSD and TGR were employed.


RESULTS
In anesthetized salt-repleted HanSD, plasma and kidney ANG II levels were higher than in salt-repleted TGR, ANG II-infused and 2K1C rats. Salt depletion caused marked increases in ANG II levels in HanSD but did not alter them in TGR. In contrast, in conscious animals immediately after decapitation plasma and kidney ANG II levels were similar in salt-repleted and salt-depleted TGR, in ANG II-infused rats, in the clipped kidney of 2K1C rats and in salt-depleted HanSD and in all these groups they were significantly higher than in salt-repleted HanSD.


CONCLUSIONS
These findings indicate that anesthesia increases plasma and kidney ANG II levels in HanSD to a greater degree than in ANG II-dependent models of hypertension. Therefore, the results from studies employing anesthetized animals must be interpreted with caution.
Husková
Zuzana
Z
Center for Experimental Medicine, Institute for Clinical and Experimental Medicine, Prague, Czech Republic.
Kramer
Herbert J
HJ
Thumová
Monika
M
Vanourková
Zdenka
Z
Bürgelová
Marcela
M
Teplan
Vladimír
V
Malý
Jan
J
Cervenka
Ludek
L
D000758:Anesthesia / Q000009:adverse effects*; D000804:Angiotensin II / Q000097:blood* / Q000378:metabolism*; D000818:Animals; D030801:Animals, Genetically Modified; D049248:Decapitation / Q000378:metabolism; D006973:Hypertension / Q000378:metabolism*; D007668:Kidney / Q000378:metabolism*; D008297:Male; D051381:Rats; D020303:Rats, Inbred Dahl; D017207:Rats, Sprague-Dawley; D012083:Renin / Q000235:genetics; D013312:Stress, Physiological / Q000378:metabolism
D000804:Angiotensin II; D012083:Renin