Background and objective: Gastrointestinal motility is influenced by abdominal trauma, laparotomy and particularly by intestinal ischaemia. The reflex inhibition of gastrointestinal motility is mediated mainly by the sympathetic nervous system. There are reports on the effects of systemically applied α2-adrenoceptor agonists on gastric emptying and recovery of bowel motility, but the effect of spinally applied α2-adrenoceptor agonists on intestinal motility has not been studied. The aim of this study was to investigate the effects of intrathecal medetomidine on gastrointestinal transit in rats after transient intestinal ischaemia.
Methods: Forty rats were randomly assigned to four groups of 10 each. Intrathecal catheter insertion and laparotomy were performed on each rat. Saline (10 μL) was injected intrathecally in Groups A and B. Medetomidine (10 μg in 10 μL) was injected intrathecally in Groups C and D. Intestinal ischaemia was induced in Groups B and D. Gastrointestinal transit was determined by measuring the length that a standardized marker meal of activated charcoal had travelled. Intrathecal medetomidine was compared to intrathecal saline in their effect on intestinal motility after 30 min period of bowel ischaemia.
Results: Laparotomy and intestinal ischaemia slowed gastrointestinal transit. Intrathecal medetomidine accelerated transit in both ischaemia and non-ischaemia groups.
Conclusion: Intrathecal medetomidine markedly accelerated small intestinal transit and may also hasten the recovery from post-ischaemic paralytic ileus.