Role of ACE/AT2R complex in the control of mesenteric resistance artery contraction induced by ACE/AT1R complex activation in response to Ang I.
OBJECTIVE
In this study, we will determine the function of the interaction between AT2R and ACE, and AT1R and ACE in the control of mesenteric resistance artery (MRA) tone from normotensive (NT) and Angiotensin II (AII)-dependent hypertensive (HT) mice.


RESULTS
Hypertension was induced by infusion of Ang-II (200 ng/kg/day) for 3 weeks. Freshly MRA (100-120 microm) were isolated from HT and NT mice and mounted in an arteriograph. Dose-response of Ang-I induced a similar contraction of MRA from NT and HT mice, which was increased after endothelium removal. AT2R antagonist (PD123319, 1 microM) significantly increased Ang-I-induced contraction of MRA from NT but not from HT mice. In addition, PD123319 significantly increased in vivo blood pressure in response to Ang-I. Luminal incubation with ACE-antibody (50 ng/ml) to block only endothelial ACE function significantly enhanced Ang-I-induced contraction of MRA from NT mice. ACE inhibitor (captopril, 10 microM) completely blocked Ang-I-induced contraction of MRA from both animals and prevented the increased blood pressure. Freshly isolated MRA subjected to immunoprecipitation, Western blot analysis and RT-PCR revealed AT1R/ACE and AT2R/ACE complexes formation, and similar AT1R, AT2R, and ACE expression level in both groups.


CONCLUSIONS
The present findings show the existence of ACE/AT2R and ACE/AT1R complexes on endothelial cells and VSMC, respectively. ACE/AT2R complex plays a modulator effect on ACE/AT1R-SMC-induced contraction of MRA, which is altered in hypertension.
Su
Jun
J
Department of Pharmacology, LSU Health Sciences Center, Tulane University, 1430 Tulane Ave, New Orleans, LA 70112, USA.
Palen
Desiree I
DI
Boulares
Hamid
H
Matrougui
Khalid
K
D000803:Angiotensin I / Q000378:metabolism* / Q000494:pharmacology; D000804:Angiotensin II / Q000378:metabolism / Q000494:pharmacology; D057912:Angiotensin II Type 2 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D000959:Antihypertensive Agents / Q000378:metabolism / Q000494:pharmacology; D002216:Captopril / Q000378:metabolism / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D007093:Imidazoles / Q000378:metabolism / Q000494:pharmacology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D008810:Mice, Inbred C57BL; D011725:Pyridines / Q000378:metabolism / Q000494:pharmacology; D044140:Receptor, Angiotensin, Type 1 / Q000235:genetics / Q000378:metabolism*; D044139:Receptor, Angiotensin, Type 2 / Q000235:genetics / Q000378:metabolism*; D012083:Renin / Q000235:genetics / Q000378:metabolism*; D014655:Vascular Resistance / Q000187:drug effects / Q000502:physiology*; D014662:Vasoconstrictor Agents / Q000378:metabolism / Q000494:pharmacology
D057912:Angiotensin II Type 2 Receptor Blockers; D000806:Angiotensin-Converting Enzyme Inhibitors; D000959:Antihypertensive Agents; D007093:Imidazoles; D011725:Pyridines; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; C073402:PD 123319; D000803:Angiotensin I; D002216:Captopril; D012083:Renin