ABSTRACT
DuP 697 (5-bromo-2[4-fluorophenyl]-3-[4-methylsulfonylphenyl]-thiophene) is a potent inhibitor of paw swelling in nonestablished and established adjuvant arthritis in rats (ED50 = 0.03 and 0.18 mg/kg/day, respectively). DuP 697 had no effect on phenylquinone writhing in rats (ED50 greater than 100 mg/kg), but was analgetic against inflammation-related pain in the Randall-Selitto assay (ED30 = 3.5 mg/kg) and was a very potent antipyretic agent (ED50 = 0.05 mg/kg). The drug was not ulcerogenic in rats at single doses up to 400 mg/kg. DuP 697 (5 mg/kg i.v.) did not alter renal blood flow or the renal vascular response to angiotensin II in furosemide-pretreated, volume-depleted rats. In contrast, indomethacin (5 mg/kg i.v.) decreased renal blood flow and potentiated the renal vascular response to angiotensin II in these animals. DuP 697 was a moderate inhibitor of bull seminal vesicle prostaglandin (PG) synthesis (IC50 = 2.4 X 10(-5) M) and a potent inhibitor of rat brain PG synthesis (IC50 = 4.5 X 10(-6) M) but was ineffective against rat kidney PG synthesis (IC50 7.5 X 10(-5) M). These differential effects of DuP 697 on PG synthesis by various tissues may account for its high potency as an anti-inflammatory and antipyretic agent and its minimal toxicity profile.
Subject(s)
Anti-Inflammatory Agents, Non-Steroidal/pharmacology , Prostaglandins/biosynthesis , Thiophenes/pharmacology , Administration, Oral , Angiotensin II/pharmacology , Animals , Anti-Inflammatory Agents, Non-Steroidal/toxicity , Cattle , Digestive System/drug effects , Rats , Rats, Inbred Strains , Renal Circulation/drug effectsABSTRACT
Intraperitoneal injection of zymosan into mice induces a peritonitis characterized by cellular influx, plasma leakage and the appearance of arachidonic acid (AA) metabolites. We report that zymosan injection also stimulates the accumulation of AA, docosahexaenoic acid, linoleic acid, and phospholipase A2 (PLA2) activity. The amount of the unsaturated fatty acids (UnFA) varies both with the zymosan dose and time. Significantly increased levels of UnFA were first detected 15 min after zymosan injection. Maximal levels of the UnFA were reached 1 to 2 h post zymosan injection (AA: 725 +/- 29 ng/mouse, docosahexaenoic acid: 296 +/- 23 ng/mouse, linoleic acid: 4489 +/- 179 ng/mouse) and declined to saline control levels by 8 h. PLA2 activity was significantly increased 5 to 15 min after zymosan injection. Maximal levels of PLA2 activity occurred 15 to 30 min after zymosan injection (31.8 +/- 9.1 nmol phospholipid/mg protein/h) and then decreased by 30% through 24 h. Neither the appearance of UnFA nor PLA2 activity correlated with cellular influx, but both were coincident with plasma exudation at 5 to 15 min after zymosan. However, maximal exudation occurred 1 to 2 h post zymosan injection similar to that seen with the UnFA but not PLA2. These latter results suggest that a significant portion of the UnFA found in the peritoneal cavity of zymosan-injected mice originates from the plasma. PLA2 activity at the early time points (5 to 15 min) may also contribute to the levels of UnFA via hydrolysis of tissue and/or cellular phospholipids.
Subject(s)
Arachidonic Acids/metabolism , Eicosanoids/metabolism , Peritonitis/metabolism , Phospholipases A/metabolism , Phospholipases/metabolism , Animals , Arachidonic Acid , Ascitic Fluid/metabolism , Chromatography, High Pressure Liquid , Exudates and Transudates/metabolism , Gas Chromatography-Mass Spectrometry , Male , Mice , Mice, Inbred Strains , Phospholipases A2 , Radioimmunoassay , Time Factors , ZymosanABSTRACT
Two "in vivo" models of inflammation have been used to investigate the role of phospholipases A2 (PLA2) in inflammation. These models are casein-induced peritonitis in the rat and zymosan-induced peritonitis in the mouse. The extracellular PLA2 activities from peritoneal lavage fluid in these two models are similar: they are calcium dependent and have broad neutral pH optima. However, the relationship between extracellular PLA2 activity and cell influx in these models are not identical. In zymosan peritonitis, PLA2 activity preceded peak cell influx, reaching a maximum within 15 min after zymosan injection, while cell influx peaked by 8 hr. In casein-induced peritonitis, the PLA2 activity peaked at 24 hr, while cell influx continued through 48 hr. The origins of the PLA2 activities in both models remain unclear; one potential source is the plasma. Understanding the role of extracellular PLA2 activity in "in vivo" models, and investigating specific inhibitors in these models may aid in our understanding of the role of extracellular PLA2 in diseases such as rheumatoid arthritis, endotoxin shock and pancreatitis.
Subject(s)
Caseins , Peritonitis/enzymology , Phospholipases A/metabolism , Zymosan , Animals , Arachidonic Acid , Arachidonic Acids/metabolism , Ascitic Fluid/enzymology , Calcium/pharmacology , Disease Models, Animal , Extracellular Space/enzymology , Hydrogen-Ion Concentration , Kinetics , Male , Mice , Peritoneal Lavage , Peritonitis/chemically induced , Phospholipases A2 , Rats , Rats, Inbred LewSubject(s)
Arachidonic Acids/pharmacology , Eicosanoids/biosynthesis , Pleura/metabolism , Pleurisy/chemically induced , Animals , Arachidonate 5-Lipoxygenase/metabolism , Arachidonic Acid , Cell Count , Cyclooxygenase Inhibitors , Hydroxyeicosatetraenoic Acids/biosynthesis , L-Lactate Dehydrogenase/metabolism , Leukotriene B4/biosynthesis , Lipoxygenase Inhibitors , Macrophages/metabolism , Macrophages/pathology , Male , Neutrophils/metabolism , Neutrophils/pathology , Pleura/drug effects , Pleura/pathology , Pleurisy/metabolism , Pleurisy/pathology , Prostaglandin-Endoperoxide Synthases/metabolism , Rats , Rats, Inbred StrainsABSTRACT
The kinetics and appearance of extracellular phospholipase A2 (PLA2) activity and its relationship to the appearance of arachidonic acid (AA) metabolites in the peritoneal cavity of mice injected with zymosan is described. AA metabolites levels including leukotriene C4 (LTC4) were maximum 15-30 min after zymosan. Peak PLA2 activity was also found 15-30 min after zymosan and was significantly increased above levels found in saline control exudates (3.83 +/- 0.89 and 0.35 +/- 0.11, respectively, p less than or equal to 0.05). Results show that an extracellular PLA2 is present in zymosan peritonitis.
Subject(s)
Peritonitis/immunology , Phospholipases A/metabolism , Phospholipases/metabolism , Animals , Arachidonic Acid , Arachidonic Acids/metabolism , Male , Mice , Peritonitis/chemically induced , Peritonitis/metabolism , Phospholipases A2 , SRS-A/metabolism , Therapeutic Irrigation , Time Factors , ZymosanABSTRACT
A radioisotopic method, originally developed for measuring the cellular response in delayed hypersensitivity lesions in mice, has been evaluated in adjuvant arthritic rats. Focal accumulation of 5-iodo-2'-deoxyuridine-125I (125IUdR) at a site of antigen challenge (left pinna) was measured and expressed as increased radioactivity in the challenged (left) over the unchallenged (right) ear (L/R ear ratio). Immunologic specificity of the assay was established with anti-lymphocyte globulin (ALG)-treated arthritic rats. ALG significantly inhibited the 125IUdR L/R ear ratio; normal rabbit globulin had no effect on this parameter. A significant negative correlation was observed between the 125IUdR ear ratios and subjective arthritic scores in established adjuvant disease. Certain characteristics of the 125IUdR radiometric ear assay in rats were established in several types of experiments: disappearance of the isotope from blood, whole body irradiation studies in turpentine-injected rats, and cyclophosphamide pretreatment in a sheep erythrocyte antigenic system. The results of this study support the utility of the 125IUdR ear assay to quantify cellular accumulation at a site of antigen challenge in adjuvant arthritic rats and possibly other antigenic systems in this species.
Subject(s)
Arthritis, Experimental/diagnostic imaging , Arthritis/diagnostic imaging , Iodine Radioisotopes , Radiometry/methods , Animals , Ear/immunology , Hypersensitivity, Delayed/diagnostic imaging , Idoxuridine , Immunity, Cellular/radiation effects , Male , Radionuclide Imaging , Rats , Rats, Inbred StrainsABSTRACT
Mepivacaine hydrochloride, 25 and 50 mg/kg sc (with sacrifice at 15 min) produced higher (p less than 0.005) drug levels in neonate (24--36-hr-old) rat brain and blood than in adult rat brain and blood; however, there was no significant difference in the brain-to-blood ratio of the drug between neonates and adults at either dose level. Intraarterial infusion of mepivacaine hydrochloride (20 micrograms/min) in adult rats resulted in measurable (GLC) mepivacaine base levels in pilocarpine-induced parotid salivary secretions collected throughout 30- and 45-min infusion periods. The saliva-to-blood ratios (+/- SEM) of mepivacaine base were 0.64 +/- 0.13 after a 30-min infusion and 2.13 +/- 0.48 after a 45-min infusion.
