Calcium-activated chloride channel (CaCC) (CaCC)

The intestinal secretory calcium-dependent pathway is a physiological mechanism responsible for the secretion of chloride ions and water into the intestinal lumen in response to elevated intracellular calcium levels (Source: NIH, 2019). This pathway is primarily mediated by calcium-activated chloride channels (CaCCs), with Anoctamin-1 (TMEM16A) being the most prominent molecular component identified in the intestinal epithelium (Source: Exp Mol Med, 2019). Activation of these channels creates an electrochemical gradient that drives chloride exit, followed by sodium and water, which helps lubricate the gut and maintain mucosal homeostasis. However, overactivation of this pathway by enterotoxins or inflammatory mediators leads to secretory diarrhea, characterized by excessive fluid loss (Source: JCI Insight, 2019). Drugs like crofelemer target this pathway by inhibiting CaCCs, thereby reducing the volume of fluid secreted into the gut (Source: FDA, 2012). This mechanism is particularly relevant in the management of non-infectious diarrhea in patients with HIV/AIDS on antiretroviral therapy. Understanding this pathway is crucial for developing antisecretory therapies that can treat various forms of watery diarrhea without significantly affecting intestinal motility.

Other names

Intestinal secretory calcium-dependent pathwaysCalcium-dependent chloride channelAnoctamin-1TMEM16AANO1

Inhibition of apical calcium-activated chloride channels to reduce the efflux of chloride ions and subsequent water loss into the intestinal lumen.