Oral rehydration solution reduces mortality in cholera despite ongoing toxin-driven chloride secretion. Its efficacy depends on which property of the small intestinal epithelium?

• A CFTR channels close in the presence of luminal glucose
• B Toxin cannot reach the jejunum once osmoles are added to the lumen
• C SGLT1-mediated sodium-glucose cotransport on villous enterocytes remains intact and pulls sodium and water across the epithelium ✓
• D Glucose stimulates local prostaglandin synthesis, restoring mucosal blood flow

Explanation

Cholera toxin cripples secretory pathways but does not affect the SGLT1 cotransporter on the apical membrane of mature villous enterocytes. Luminal glucose drives sodium absorption against the secretory drive, and water follows iso-osmotically through paracellular and transcellular routes. This dissociation between intact absorptive transport and defective secretory control is the entire rationale for glucose-based oral rehydration therapy.

Reference: Guyton and Hall Textbook of Medical Physiology, 14th ed.

High-yield for: NEET PGINI-CETNExTFMGEUSMLEPLABMRCP

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