Effects of lipopolysaccharide and phenylbutazone on gastric contents in the horse.
Authors: Doherty T J, Andrews F M, Blackford J T, Rohrbach B W, Sandin A, Saxton A M
Journal: Equine veterinary journal
Summary
# Editorial Summary: Lipopolysaccharide and Phenylbutazone Effects on Equine Gastric Contents Endotoxaemia disrupts gastrointestinal motility in horses, yet little was known about its impact on gastric secretion itself until this 2003 work by Doherty and colleagues. Using fasted horses with permanent gastric cannulae, researchers administered lipopolysaccharide (LPS)—a toxic component of Gram-negative bacteria—with or without prior phenylbutazone pretreatment, then collected gastric samples at 15-minute intervals over three hours to assess changes in acid, sodium and potassium output. LPS significantly reduced gastric acid output and potassium concentration whilst paradoxically increasing sodium levels and output, effects that phenylbutazone partially reversed, particularly regarding secreted volume and sodium changes. These findings suggest that prostaglandins mediate, at least in part, LPS-induced alterations to gastric secretion, offering a mechanistic explanation for why endotoxaemic horses may experience altered gastric chemistry alongside compromised motility. For practitioners managing colicky or systemically unwell horses, this work highlights that endotoxaemia affects not just gut movement but the stomach's chemical environment, with potential implications for mucosal protection and acid-base balance—though further research is needed to fully characterise the source and clinical significance of these compositional shifts.
Read the full abstract on PubMed
Practical Takeaways
- •Endotoxaemic horses experience altered gastric acid secretion and electrolyte composition that may contribute to gastrointestinal complications during systemic infection
- •NSAIDs like phenylbutazone may provide some protection against endotoxin-induced changes in gastric secretion, though effects are partial
- •Understanding endotoxin effects on gastric function helps explain gastrointestinal dysfunction in colicky or septic horses and may guide supportive treatment strategies
Key Findings
- •LPS significantly decreased gastric acid output, potassium concentration and potassium output in horses
- •LPS increased sodium concentration and sodium output in gastric contents
- •Phenylbutazone pretreatment did not affect basal gastric acid secretion but partially blocked LPS-induced changes in secreted volume, sodium concentration and sodium output
- •LPS-induced changes in gastric secretion appear to be mediated in part by prostaglandins