Colonic transit time (CTT)

Colonic transit time (CTT) is a physiological measurement representing the duration required for intraluminal contents to pass through the large intestine, from the cecum to the rectum [1]. It is not a specific molecular target like a receptor or enzyme, but rather a clinical endpoint and a marker of colonic motor function used to evaluate gastrointestinal disorders. CTT is influenced by a complex interplay of enteric nervous system activity, smooth muscle contractility, and epithelial fluid secretion [4]. In clinical practice, delayed CTT is a hallmark of slow-transit constipation, whereas accelerated CTT is characteristic of diarrheal states, such as IBS-D [5]. Pharmacological intervention aimed at normalizing CTT typically involves targeting specific proteins, such as serotonin receptors (e.g., 5-HT4), chloride channels (e.g., ClC-2), or opioid receptors, to either stimulate or inhibit motility and fluid dynamics [2,3]. Assessing CTT via radio-opaque markers or wireless motility capsules remains a gold standard for diagnosing functional defecation disorders and monitoring the efficacy of prokinetic or laxative therapies [6]. Sources: [1] Southwell, B. R., et al. (2014). 'Methods for the assessment of colonic transit time.' Nature Reviews Gastroenterology & Hepatology. PubMed PMID: 24713221. [2] Layer, P., et al. (2017). 'Linaclotide in irritable bowel syndrome with constipation.' Therapeutic Advances in Gastroenterology. [3] Baker, D. E. (2007). 'Loperamide: a review of its use in the management of acute and chronic diarrhea.' Reviews in Gastroenterological Disorders. [4] StatPearls (2023). 'Physiology, Gastrointestinal Motility.' NCBI Bookshelf. [5] Rao, S. S., et al. (2009). 'Diagnosis and management of chronic constipation.' American Journal of Gastroenterology. [6] Camilleri, M., et al. (2010). 'Wireless motility capsule: a new tool in the armamentarium for gastrointestinal motility disorders.' Gut.

Other names

Large bowel transit timeGut transit timeTotal colonic transit timeWhole gut transit time

Drugs modulate colonic transit time by acting as agonists or antagonists on molecular targets within the enteric nervous system or intestinal epithelium. Prokinetic agents like Prucalopride stimulate 5-HT4 receptors to enhance peristalsis [1], while secretagogues like Linaclotide activate guanylate cyclase-C (GC-C) to increase intestinal fluid, thereby accelerating transit [2]. Conversely, antimotility agents like Loperamide activate mu-opioid receptors to slow transit for the treatment of diarrhea [3].