title: Antihypertensive therapy increases tetrahydrobiopterin levels and NO/cGMP signaling in small arteries of angiotensin II-infused hypertensive rats.
abstract: We previously reported that small mesenteric arteries from hypertensive rats have increased NOS-derived H(2)O(2) and reduced NO/cGMP signaling. We hypothesized that antihypertensive therapy lowers blood pressure through a tetrahydrobiopterin (BH(4))-dependent mechanism restoring NO/cGMP signaling and endothelial NOS (NOS3; eNOS) phosphorylation in small arteries. To test this hypothesis, small mesenteric arteries from normotensive rats (NORM), angiotensin II-infused rats (ANG), ANG rats with triple therapy (reserperine, hydrochlorothiazide, and hydralazine), or ANG rats with oral BH(4) therapy were studied. Both triple therapy and oral BH(4) therapy attenuated the rise in systolic blood pressure in ANG rats and restored NO/cGMP signaling in small arteries similarly. Triple therapy significantly increased vascular BH(4) levels and BH(4)-to-BH(2) ratio similar to ANG rats with BH(4) supplementation. Furthermore, triple therapy (but not oral BH(4) therapy) significantly increased GTP cyclohydrolase I (GTPCH I) activity in small arteries without a change in expression. NOS3 phosphorylation at Ser1177 was reduced in small arteries from ANG compared with NORM, while NOS3 phosphorylation at Ser633 and Thr495 were similar in ANG and NORM. NOS3 phosphorylation at Ser1177 was restored with triple therapy or oral BH(4) in ANG rats. In conclusion, antihypertensive therapy regulates NO/cGMP signaling in small arteries through increasing BH(4) levels and NOS3 phosphorylation at Ser1177.
authors.affiliation: Vascular Biology Center, CB 3213, Medical College of Georgia, Augusta, GA 30912, USA.
authors.forename: Kyu-Tae
authors.initials: KT
authors.lastname: Kang
authors.forename: Jennifer C
authors.initials: JC
authors.lastname: Sullivan
authors.forename: Frank T
authors.initials: FT
authors.lastname: Spradley
authors.forename: Livius V
authors.initials: LV
authors.lastname: d'Uscio
authors.forename: Zvonimir S
authors.initials: ZS
authors.lastname: Katusic
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Pollock
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D001708:Biopterins / Q000031:analogs & derivatives* / Q000097:blood / Q000627:therapeutic use; D006152:Cyclic GMP / Q000378:metabolism; D006136:GTP Cyclohydrolase / Q000378:metabolism; D006830:Hydralazine / Q000627:therapeutic use; D006852:Hydrochlorothiazide / Q000627:therapeutic use; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D008297:Male; D008638:Mesenteric Arteries / Q000187:drug effects* / Q000503:physiopathology; D009569:Nitric Oxide / Q000378:metabolism; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012110:Reserpine / Q000627:therapeutic use; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology
chemical_list: D000959:Antihypertensive Agents; D006852:Hydrochlorothiazide; D000804:Angiotensin II; D001708:Biopterins; D006830:Hydralazine; D009569:Nitric Oxide; D012110:Reserpine; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; D006136:GTP Cyclohydrolase; C003402:sapropterin; D006152:Cyclic GMP