Substance P receptor expression in intestinal epithelium in Clostridium difficile toxin A enteritis in rats

• Published in: American journal of physiology: Gastrointestinal and liver physiology 1998-07, Vol.275 (1), p.G68-G75
• Main Authors: Pothoulakis, Charalabos, Castagliuolo, Ignazio, Leeman, S E, Wang, Chi-Chung, Li, Hanzong, Hoffman, Beth J, Mezey, Eva
• Format: Article
• Language: English
• ISSN: 0193-1857; 1522-1547
• DOI: 10.1152/ajpgi.1998.275.1.G68

We previously reported that the inflammatory effects of Clostridium difficile toxin A on rat intestine can be significantly inhibited with a specific neurokinin-1 receptor (NK-1R) antagonist. In this study we investigated the localization and expression of NK-1R mRNA and protein in rat intestine by in situ hybridization, Northern blot analysis, and immunohistochemistry, respectively, after exposure to toxin A. Northern blot analysis showed increased mucosal levels of NK-1R mRNA starting 30 min after toxin A administration. In situ hybridization showed that toxin A increased NK-1R mRNA expression in intestinal epithelial cells after 30, 120, and 180 min. In rats pretreated with the NK-1R antagonist CP-96345 the increase in NK-1R mRNA levels after exposure to toxin A was inhibited, indicating that NK-1R upregulation is substance P (SP) dependent. One hour after exposure to toxin A many of the intestinal epithelial cells showed staining for NK-1R compared with controls. Specific I-SP binding to purified epithelial cell membranes obtained from ileum exposed to toxin A for 15 min was increased twofold over control and persisted for 4 h. This report provides evidence that NK-1R expression is increased in the intestinal epithelium shortly after exposure to toxin A and may be important in toxin A-induced inflammation.