title: Myocardial protection after systemic application of L-arginine during reperfusion.
abstract: The L-arginine-nitric oxide (NO) pathway plays an important role in ischemia-reperfusion injury. In the present study we investigated the role of NO-precursor L-arginine on cardiac and pulmonary function after reversible hypothermic ischemia. Twelve anesthetized dogs underwent cardiopulmonary bypass. After 60 minutes of hypothermic cardiac arrest, reperfusion was started with application of either saline vehicle (control, n = 6) or L-arginine (40 mg/kg i.v. bolus then 3 mg/kg i.v. infusion during the first 20 minutes of reperfusion, n = 6). The vasodilative response to acetylcholine was significantly higher in the L-arginine group (P < 0.05). The preload recruitable stroke work of the left ventricle decreased significantly after reperfusion, however remained unchanged in the L-arginine group. Arterial blood gas analysis did not show any difference between the two groups. Plasma L-arginine concentration reached peak level at 20 minutes of administration (675.0 +/- 66.6 versus 207.7 +/- 14.5 in the L-arginine group, P < 0.05) and returned to baseline at 40 minutes, while in the control group remained unchanged during ischemia and reperfusion (276.2 +/- 71.6 versus 283.8 +/- 38.5, P < 0.05). Plasma nitrite concentration followed L-arginine changes parallel, however nitrate levels increased slower. Supplementation with L-arginine during reperfusion prevents myocardial and endothelial dysfunction, however does not have any overriding effect on pulmonary function. Considerably rapid elimination of plasma L-arginine was demonstrated during early reperfusion.
authors.affiliation: Department of Cardiac Surgery, University of Heidelberg, Germany. soospal@hermes.sote.hu
authors.forename: Pál
authors.initials: P
authors.lastname: Soós
authors.forename: Terézia
authors.initials: T
authors.lastname: Andrási
authors.forename: Volker
authors.initials: V
authors.lastname: Buhmann
authors.forename: Brigitte
authors.initials: B
authors.lastname: Kohl
authors.forename: Christian
authors.initials: C
authors.lastname: Vahl
authors.forename: Siegfried
authors.initials: S
authors.lastname: Hagl
authors.forename: Gábor
authors.initials: G
authors.lastname: Szabó
mesh_terms: D000818:Animals; D001120:Arginine / Q000008:administration & dosage*; D004285:Dogs; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism*; D009206:Myocardium / Q000378:metabolism*; D009569:Nitric Oxide / Q000378:metabolism
chemical_list: D009569:Nitric Oxide; D001120:Arginine