Renal microvascular actions of angiotensin II fragments.
In the present study, we investigated renal microvascular responses to ANG-(1-7) and ANG IV. Diameter changes of small interlobular arteries, afferent arterioles, and efferent arterioles were assessed by using isolated perfused hydronephrotic rat kidneys. ANG-(1-7) and ANG IV concentration dependently decreased the diameters of all investigated renal microvessel, however, with a much lower potency than ANG II. The ANG II type 1 receptor blocker irbesartan completely reversed the responses to ANG-(1-7) and ANG IV, whereas the ANG II type 2 receptor blocker PD-123319 had no effect. Both ANG-(1-7) and ANG IV failed to alter renal microvascular constriction induced by ANG II. In addition, subnanomolar concentrations of ANG-(1-7) had no effect on the myogenic-induced tone of interlobular arteries and afferent arterioles. Thus our data indicate that at high concentrations, ANG-(1-7) and ANG IV are able to activate the ANG II type 1 receptor, thereby inducing renal microvascular constriction. The failure of ANG-(1-7) and ANG IV to reduce ANG II- and pressure-induced constrictions suggests that these fragments do not exert a vasodilator and/or ANG II antagonistic action in the kidney.
van Rodijnen
William F
WF
Laboratory for Physiology, Institute for Cardiovascular Research, Vrije Universiteit Medical Center, 1081 BT Amsterdam, The Netherlands. W.van_Rodijnen.physiol@med.vu.nl
van Lambalgen
Ton A
TA
van Wijhe
Michiel H
MH
Tangelder
Geert-Jan
GJ
Ter Wee
Piet M
PM
D000803:Angiotensin I; D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000494:pharmacology*; D000818:Animals; D006869:Hydronephrosis / Q000503:physiopathology; D066298:In Vitro Techniques; D008297:Male; D008833:Microcirculation / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin / Q000378:metabolism; D012079:Renal Circulation / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects
D010446:Peptide Fragments; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D011945:Receptors, Angiotensin; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C012877:angiotensin II, des-Asp(1)-des-Arg(2)-Ile(5)-; D000803:Angiotensin I; C118790:angiotensin I (1-7)