Abstract
Objectives
To determine the in vitro effect of various prostaglandins (PG) and nonsteroidal anti-inflammatory drugs (NSAID) on contractile activity of the large-colon taenia of horses.
Animals
14 healthy horses.
Procedure
The taenia was collected from the ventral colon, cut into strips (2 × 10 mm), and mounted in a tissue bath system (20-ml capacity) that contained oxygenated Krebs buffer solution warmed to 37.5 ± 0.5 C. After equilibration, incremental doses of PGE2, PGF2α, PGI2, flunixin meglumine, carprofen, ketoprofen, and phenylbutazone were added to the baths, and contractile activity was recorded. Magnitude of the response was calculated by comparing contractile activity before and after administration of the PG or NSAID to the tissue baths.
Results
PGE2 and PGF2α caused a significant increase in contractile activity, whereas PGL2 induced an inhibitory response. Activity of NSAID on contraction was predominantly inhibitory. At low concentrations, ketoprofen induced an excitatory effect, which then became inhibitory at high concentrations. Compared with the other NSAID, carprofen significantly reduced contractile activity at lower concentrations.
Conclusions
PGE2 and PGF2α appear to enhance contractility of large-colon taenia of horses, whereas PGL2 was inhibitory in the in vitro model. Administration of NSAID also inhibited contractility, with carprofen having the most potent effect.
Clinical Relevance
Administration of NSAID in combination with liberation of endogenous PG may predispose horses to development of intestinal stasis and subsequent impaction. (Am J Vet Res 1999;60:1004-1009)
