1995 Volume 48 Issue 2 Pages 89-101
The effect of chloramphenicol (CAP) on the intestinal motility of mice was studied. Acute and chronic CAP treatment significantly increased the food transit time. CAP produced concentration-dependent inhibition of motility of the isolated ileum of mice. Prazosin, propranolol, atropine, ouabain and chlorpromazine all failed to modulate or counteract the CAP-induced inhibition of ileal motility. However, naloxone and hexamethonium slightly modified the inhibitory response of CAP. The inhibitory response of CAP was markedly counteracted by cystine, a guanylate cyclase inhibitor. CAP increased the activity of Ca++-ATPase in the ileum in all experiments. Our results suggest that the CAP-induced inhibition of the intestinal motility is not mediated through adrenergic, cholinergic and cAMP or through inhibition of the electrogenic pump. Compared to thiamphenicol (TAP), CAP, with a p-NO2 group in its structure, exhibited more pronounced alteration of both intestinal motility and Ca++-ATPase activity. We, therefore, suggest that greater inhibition of ileal motility induced by CAP is possibly a p-NO2-cGMP-Ca++-ATPase-mediated mechanism.