Asymmetric dimethylarginine increases myogenic reactivity in mesenteric arteries of non-rupp rats when compared to rupp rats

Autor: Rolando J. Ramirez, Julianna Matthews, Jacqueline Novak, Paul Speer
Rok vydání: 2004
Předmět:
Zdroj: American Journal of Obstetrics and Gynecology. 191:S33
ISSN: 0002-9378
DOI: 10.1016/j.ajog.2004.09.111
Popis: MESENTERIC ARTERIES OF NON-RUPP RATS WHEN COMPARED TO RUPP RATS PAUL SPEER, ROLANDO RAMIREZ, JULIANNA MATTHEWS, JACQUELINE NOVAK, University of Pittsburgh, Obstetrics, Gynecology and Reproductive Sciences, Pittsburgh, Pennsylvania, University of Pittsburgh, Magee-Womens Research Institute, Pittsburgh, Pennsylvania OBJECTIVE: Asymmetric dimethylarginine (ADMA), an endogenous inhibitor of NOS, is increased in preeclamptic pregnancies. Increased ADMA has been linked to oxidative stress generated by reduced placental perfusion and may contribute to preeclampsia by decreasing NO synthesis. Myogenic reactivity is increased in mesenteric arteries in a rat model of reduced uterine perfusion pressure (RUPP). We hypothesized that, when exposed to ADMA, mesenteric arteries from pregnant non-RUPP (SHAM) rats, would exhibit increased myogenic reactivity similar to mesenteric arteries from pregnant RUPP rats. STUDY DESIGN: Mesenteric arteries (200-250 mm) were dissected from pregnant RUPP rats (n = 3), pregnant SHAM rats (surgical control, n = 2), and non-pregnant rats (n = 3) on day 20 of gestation. Myogenic reactivity was assessed using pressure arteriograph. Vessels were either pre-treated with ADMA 1mM or non-treated. After phenylephrine constriction intraluminal pressure was increased stepwise from 20-120 mm Hg. Myogenic responses were normalized as a % change in vessel diameter compared to the initial diameter at 20 mm Hg. Myogenic reactivity is greatest in arteries that demonstrate the smallest percent change in diameter with increasing pressure. Values expressed are mean % change. RESULTS: Arteries from the SHAM animals were less myogenic than arteries from the RUPP rats or nonpregnant controls. At 100 mm Hg, vessel diameter in the SHAM animals increased by 50% compared to only 22% in ADMA treated vessels. In arteries isolated from RUPP animals myogenic reactivity was increased compared to the SHAM animals and reactivity was not increased by ADMA treatment. ADMA had no effect on the arteries isolated from nonpregnant control rats. CONCLUSION: ADMA increases myogenic reactivity in pregnant SHAM rats but has little effect on pregnant RUPP rats. The increased myogenic reactivity observed in mesenteric arteries from RUPP rats may occur from NOS dysfunction independent of ADMA.
Databáze: OpenAIRE
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