European journal of pharmacology
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Comparative Study
Quantitative comparison of the analgesic and anti-inflammatory activities of aspirin, phenacetin and acetaminophen in rodents.
The mild analgesic activities of aspirin, phenacetin and acetaminophen have been compared in the trypsin, kaolin and carrageenan hyperalgesic assays as well as in the acetic acid writhing test. The trypsin and kaolin hyperalgesic assays were designed to be unaffected by drugs with anti-inflammatory activity. Aspirin and acetaminophen were inactive in these two tests at dose levels devoid of side effects. ⋯ Both of these latter drugs were active in the carrageenan pleurisy and adjuvant arthritis models of inflammation. In all studies phenacetin was equipotent to or more potent than acetaminophen. The data suggest that the analgesia produced by aspirin and acetaminophen results from their anti-inflammatory activity whereas the analgesia produced by phenacetin has two components, one dependent on and one independent of anti-inflammatory activity.
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The release of histamine and mortality was studied in mice after various types of experimental shock. In burn shock, serum histamine rose significantly after injury, but there was no correlation between increased serum histamine and high mortality as a consequence of several therapy regimens. For example, after treatment with histamine or Compound 48/80 before burning, there was a rise of serum histamine, yet shock mortality fell significantly. ⋯ In tourniquet shock, serum histamine rose significantly, and treatment with both antagonists before trauma produced a significant elevation of shock mortality. In endotoxin shock, prior treatment with one or both drugs did not change mortality. These results suggest that endogenous histamine is not a lethal factor in burn and tourniquet trauma, but rather it appears to have a compensatory, beneficial effect.
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This study was designed to investigate the splanchnic congestion and gastrointestinal lesions frequently found in calves during anaphylaxis. Calves were sensitised to horse serum and the following cardiovascular parameters monitored; carotid arterial pressure, mesenteric arterial pressure, mesenteric venous pressure, mesenteric arterial flow, and abdominal venous pressure. ⋯ It is suggested that during anaphylaxis a rise in hepatic vascular resistance occurs, resulting in pooling of blood in the venous side of the mesenteric vasculature and possibly in the liver itself. This increase in hepatic resistance may be caused by circulating vasoactive agents released by the anaphylactic process, a local Schultz-Dale type reaction, or a reflex triggered by systemic baroreceptors.