Effect of L-NAME on pulmonary arterial pressure, plasma nitric oxide and pulmonary hypertension syndrome morbidity in broilers.
1. Experiments were conducted to evaluate the effect of a synthetic inhibitor of nitric oxide (NO) synthase (L-NAME) on pulmonary arterial pressure (PAP) and pulmonary hypertension syndrome (PHS) morbidity in broilers. 2. In Experiment 1, broilers were infused intravenously with L-NAME, and the mean pulmonary arterial pressure (mean PAP) and plasma NO were measured at 0, 1, 2 and 4 h after the start of infusion. The mean PAP increased and plasma NO was reduced at 1 to 2 h in broilers treated with L-NAME. 3. In Experiment 2, 180 Arbor Acres broilers were evenly divided into three groups: a control group (group C), and two groups exposed to low environmental temperatures and fed a 3, 3, 5-triiodothyronine (T3) supplemented diet alone (group A) or also including 100 ppm L-NAME (group B). 4. The PHS morbidity of group A was higher than for group C but lower than for group B. Plasma endothelin-1 was higher in broilers in groups A and B than in group C. Plasma NO was not significantly lower in broilers of group B when compared with those in group A. 5. The right/total ventricular weight ratio (RV/TV) and mean PAP were higher in groups A and B than in group C, and the RV/TV ratio increased one week earlier in group B than in group A. 6. These results suggest that L-NAME increases broiler PAP by inhibiting the endogenous synthesis of NO, leading to pulmonary hypertension, right ventricular hypertrophy and the increased morbidity of PHS in broilers.
D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D002645:Chickens; D004305:Dose-Response Relationship, Drug; D019332:Endothelin-1 / Q000097:blood; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006976:Hypertension, Pulmonary / Q000453:epidemiology / Q000209:etiology / Q000662:veterinary*; D015994:Incidence; D007275:Injections, Intravenous / Q000662:veterinary; D009017:Morbidity; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D009569:Nitric Oxide / Q000097:blood*; D011201:Poultry Diseases / Q000453:epidemiology* / Q000209:etiology; D011651:Pulmonary Artery / Q000502:physiology; D011897:Random Allocation; D013577:Syndrome; D014655:Vascular Resistance / Q000187:drug effects; D014664:Vasodilation / Q000187:drug effects
D019332:Endothelin-1; D004791:Enzyme Inhibitors; D009569:Nitric Oxide; D019331:NG-Nitroarginine Methyl Ester