Nitric oxide inhibits leucocyte migration in carrageenin-induced rat pleurisy.
OBJECTIVE
The role of nitric oxide (NO) on leucocyte migration has been investigated in rat carrageenin-induced pleurisy.


METHODS
Male Wistar rats.


METHODS
L-arginine, NOC-18 and aminoguanidine were administered subcutaneously 1 h prior to carrageenin injection.


METHODS
Leucocyte accumulation into the pleural cavity was measured 4 h after carrageenin challenge. Statistical significance was calculated by Bonferroni test.


RESULTS
L-arginine (10 mg/kg) or the NO donor NOC-18 (10 mg/kg), significantly inhibited leucocyte infiltration by 31% and 20% respectively (P<0.01). On the contrary, when these compounds were given at high doses (L-arginine 300 mg/kg; NOC-18 30 mg/kg), leucocyte accumulation was increased by 22% and 33% respectively (P<0.01). Aminoguanidine, a relatively selective inhibitor of the inducible NO synthase, depending on the dose, showed a biphasic effect on cell migration. Thus, at low doses (30 and 100 mg/kg), aminoguanidine increased (by 40% and 74% respectively, P< 0.01) leucocyte infiltration which was inhibited by 41% (P < 0.01) when the drug was given at high dose (300 mg/kg).


CONCLUSIONS
These results suggest that in rat carrageenin-induced pleurisy NO primarily inhibits leucocyte migration.
Ialenti
A
A
Department of Experimental Pharmacology, University of Naples Federico II, Italy.
Ianaro
A
A
Maffia
P
P
Sautebin
L
L
Di Rosa
M
M
D000818:Animals; D001120:Arginine / Q000008:administration & dosage / Q000494:pharmacology; D001794:Blood Pressure; D002351:Carrageenan; D002465:Cell Movement / Q000187:drug effects*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006146:Guanidines / Q000008:administration & dosage / Q000494:pharmacology; D007962:Leukocytes / Q000502:physiology*; D008297:Male; D009569:Nitric Oxide / Q000494:pharmacology*; D020030:Nitric Oxide Donors / Q000008:administration & dosage / Q000494:pharmacology; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D052247:Nitric Oxide Synthase Type II; D009603:Nitroso Compounds / Q000008:administration & dosage / Q000494:pharmacology; D010994:Pleura / Q000473:pathology; D010996:Pleural Effusion / Q000473:pathology / Q000503:physiopathology; D010998:Pleurisy / Q000139:chemically induced / Q000473:pathology*; D051381:Rats; D017208:Rats, Wistar
D004791:Enzyme Inhibitors; D006146:Guanidines; C093285:NOC 18; D020030:Nitric Oxide Donors; D009603:Nitroso Compounds; D009569:Nitric Oxide; D002351:Carrageenan; D001120:Arginine; D019001:Nitric Oxide Synthase; D052247:Nitric Oxide Synthase Type II; C496318:Nos2 protein, rat; C004479:pimagedine