Changes in plasma angiotensin-converting enzyme activity and noradrenaline responses to long-term nitric oxide inhibition vary depending on their basal values in chickens.
In this study, we investigated the effects of N(omega)-nitro-L-arginine (L-NNA) on arterial blood pressure (BP), plasma noradrenaline (NA) and adrenaline (A) levels and angiotensin-converting enzyme (ACE) activity. L-NNA was applied with tap water (1 mg/ml) from the 3rd to the 8th week of age (group L-NNA1). In Experiment 1, long-term L-NNA application increased BP compared to the control group (group C1) (L-NNA1 = 131.4 +/- 6.3, n = 6; C1 = 82.7 +/- 4.7 mm Hg, n = 7) but decreased plasma noradrenaline and adrenaline levels and ACE activity (NA levels: C1 = 15.5 +/- 0.8, n = 7; L-NNA1 = 8.6 +/- 0.5 ng/ml, n = 7; A levels: C1 = 15.5 +/- 0.8, n = 7; L-NNA1 = 6.0 +/- 0.5 ng/ml, n = 7; ACE activities: C1 = 87.3 +/- 3.1, n = 6; L-NNA1 = 46.2 +/- 1.9 U/l, n = 5). On the other hand, in Experiment 2 (carried out under the same conditions and in age-matched chickens), blood pressure, plasma noradrenaline levels and ACE activity were found to differ in the control group (C2) (BP = 141.4 +/- 15.5 mm Hg, n = 7; NA = 1.1 +/- 0.4 ng/ml, n = 7; ACE = 57.2 +/- 5.3 U/l, n = 7) as compared to C1, while plasma adrenaline levels were similar. In this series, long-term L-NNA application (group L-NNA2) did not change the BP, but surprisingly increased noradrenaline and ACE values (values of L-NNA2: BP = 165.7 +/- 15.6 mm Hg, n = 7; NA = 9.3 +/- 1.3 ng/ml, n = 8; ACE = 149.4 +/- 16 U/l, n = 8) while decreasing plasma adrenaline levels. L-arginine addition to L-NNA treatment completely reversed plasma noradrenaline and ACE activity values. These results indicate the modulatory activity of an L-arginine-NO pathway on adrenaline release as well as on the renin-angiotensin system in chickens.
Aksulu
H E
HE
Firat University, Faculty of Medicine, Department of Pharmacology, Elazig, Turkey.
Bingöl
I
I
Karatas
F
F
Sagmanligil
H
H
Ustündag
B
B
D000818:Animals; D001120:Arginine / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects; D002645:Chickens / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D004837:Epinephrine / Q000097:blood; D008297:Male; D009569:Nitric Oxide / Q000037:antagonists & inhibitors*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D019335:Nitroarginine / Q000494:pharmacology; D009638:Norepinephrine / Q000097:blood*; D007703:Peptidyl-Dipeptidase A / Q000097:blood*; D012083:Renin / Q000097:blood
D004791:Enzyme Inhibitors; D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine; D019001:Nitric Oxide Synthase; D007703:Peptidyl-Dipeptidase A; D012083:Renin; D009638:Norepinephrine; D004837:Epinephrine