ABSTRACT
Nitro-L-arginine methyl ester (0.15 mumol/paw) significantly reduced both bradykinin- and 5-hydroxytryptamine-induced rat paw oedema. At this dose, L-arginine (L-Arg), D-Arg and nitro-D-arginine methyl ester had no effect on the oedematogenic responses induced by these agents. Nitro-L-arginine methyl ester, nitro-D-arginine methyl ester, L-Arg, D-Arg, L-arginine methyl ester and L-arginine ethyl ester, at the dose of 15 mumol/paw, significantly potentiated both bradykinin- and 5-hydroxytryptamine-induced oedema. This potentiation was not observed in animals treated with both mepyramine and methysergide or in animals chronically treated with compound 48/80. Nitro-L-arginine methyl ester (0.3-3 mM) and L-Arg (0.3-3 mM) released small amounts (< 10%) of histamine from rat peritoneal mast cells when compared to compound 48/80-induced degranulation (> 40%). Histamine release was quantified by radioimmunoassay since nitro-L-arginine methyl ester and L-Arg interfere with the fluorometric assay. The potentiation of paw oedema observed with higher doses of all arginine analogues is caused by in vivo mast cell degranulation and is probably due to the cationic charge of these substances.
Subject(s)
Arginine/analogs & derivatives , Inflammation/immunology , Mast Cells/drug effects , Nitric Oxide/antagonists & inhibitors , Animals , Arginine/pharmacology , Bradykinin/pharmacology , Edema/chemically induced , Edema/immunology , Hindlimb , Histamine Release/drug effects , Male , Mast Cells/metabolism , Methysergide/pharmacology , NG-Nitroarginine Methyl Ester , Pyrilamine/pharmacology , Radioimmunoassay , Rats , Rats, Wistar , Serotonin/metabolism , Serotonin/pharmacologyABSTRACT
The purpose of the present study was to examine the protective action of a 7.5% hypertonic NaCl solution (HS) on the circulatory shock produced by compound 48/80 (48/80) in rats and to determine the effect of the AV3V lesion on the protective action of HS. Intravenous injection of 48/80 into sham-operated rats resulted in an immediate drop of mean arterial pressure (MAP). In sham-operated rats, intravenous injection of HS prevented the drop of MAP produced by 48/80, but HS was ineffective in AV3V-lesioned rats. These results show that HS had a protective action on the circulatory shock produced by 48/80 and that the AV3V region plays an important role in this protective action.
Subject(s)
Saline Solution, Hypertonic/therapeutic use , Shock/therapy , p-Methoxy-N-methylphenethylamine/pharmacology , Animals , Cerebral Ventricles/surgery , Male , Rats , Rats, Inbred Strains , Shock/etiology , Shock/prevention & controlABSTRACT
The purpose of the presente study was to examine the protective action of a 7.5% hypertonic NaCl solution (HS) on the ciruclatory shock produced by compound 48/80 (48/80) in rats and to determine the effect of the AV3V lesion on the protective action of HS. Intravenous injection of 48/80 into sham-operated rats resulted in an innediate drop of mean arterial pressure (In sham-operated rats, intravenous inection of HS prevented the drop of MAP produced by 48/80, but HS was ineffective in AV3V-lesioned rats. These results show that HS had a protective action on the circularory shock produced by 48/80 and that the AV3V region plaus an important role in this protective action
