Intestinal adenylate cyclase–cAMP–chloride secretion pathway (AC-cAMP-Cl- pathway)

The intestinal adenylate cyclase–cAMP–chloride secretion pathway is a fundamental physiological mechanism responsible for regulating the movement of water and electrolytes across the intestinal epithelium. This pathway is initiated when various stimuli, such as hormones or bacterial toxins, activate adenylate cyclase (AC) within enterocytes, leading to an increase in intracellular cyclic adenosine monophosphate (cAMP) [StatPearls, 2023]. The elevated cAMP levels activate Protein Kinase A (PKA), which then phosphorylates the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR), a primary apical chloride channel [Journal of Cell Science, 2000]. The resulting efflux of chloride ions into the intestinal lumen creates an osmotic gradient that pulls sodium and water into the gut, facilitating fluid secretion [StatPearls, 2023]. Pathological overactivation of this pathway by toxins from pathogens like Vibrio cholerae results in severe secretory diarrhea and life-threatening dehydration [StatPearls, 2023]. Conversely, defects in the CFTR component of this pathway lead to Cystic Fibrosis, characterized by impaired secretion and thickened mucus [Journal of Cell Science, 2000]. Therapeutic strategies targeting this pathway include CFTR inhibitors like crofelemer for treating diarrhea and agents that modulate cAMP levels, such as racecadotril or octreotide, to manage intestinal motility and secretion [PubChem, 2024; PubMed, 2000; StatPearls, 2023]. Understanding this pathway is crucial for developing treatments for both hypersecretory states and conditions involving impaired intestinal fluid transport.

Other names

cAMP-dependent chloride secretionCFTR-mediated secretion pathwayIntestinal fluid secretion pathway

Activation of adenylate cyclase increases intracellular cAMP, which activates Protein Kinase A (PKA), leading to the phosphorylation and opening of the Cystic Fibrosis Transmembrane Conductance Regulator (CFTR) chloride channel, causing chloride and water secretion into the intestinal lumen.