Water and electrolyte transport by rabbit esophagus

Area of Science:

• Gastroenterology
• Physiology
• Epithelial Transport

Background:

• The electrical properties and ion transport mechanisms of the esophagus are crucial for understanding its function.
• Previous research has indicated potential differences across epithelial tissues, but specific mechanisms in the esophagus require elucidation.

Purpose of the Study:

• To investigate the transmural electrical potential difference in rabbit esophagus.
• To characterize the water and electrolyte transport mechanisms across the esophageal epithelium.

Main Methods:

• In vivo and in vitro studies were conducted on rabbit esophagus.
• Electrical potential difference, short-circuit current, and tissue resistance were measured.
• Ion transport was assessed using various electrolyte solutions and pharmacological inhibitors.

Main Results:

• The rabbit esophagus exhibited a lumen-negative potential difference in vivo (-28 mV) and in vitro (-17.9 mV).
• In vitro, a short-circuit current of 12.9 µA/cm² and resistance of 1,466 Ω·cm² were recorded.
• Active mucosal-to-serosal sodium transport accounted for 77% of the short-circuit current, with chloride transport contributing 14%.

Conclusions:

• Active sodium transport is the principal determinant of the electrical potential difference and short-circuit current in the rabbit esophageal epithelium.
• Anion transport, particularly chloride, also contributes to the observed electrical currents.
• These findings highlight the role of active ion transport in esophageal physiology.