Microelectrode studies of Necturus antral mucosa: electrical potentials and resistances

Area of Science:

• Physiology
• Electrophysiology
• Epithelial Transport

Background:

• Understanding epithelial transport is crucial for physiological studies.
• Necturus antral mucosa serves as a model for investigating gastric epithelial function.
• Previous studies have explored electrical properties, but detailed pathway resistance remains key.

Purpose of the Study:

• To precisely measure the electrical potentials and resistances of cell membranes and the shunt pathway in Necturus antral mucosa.
• To elucidate the contributions of transcellular and paracellular pathways to overall transepithelial resistance.
• To quantify the electrical resistance of apical membrane, basolateral membrane, and shunt pathways.

Main Methods:

• Intracellular microelectrode impalement techniques were employed on Necturus antral mucosa.
• Stable impalements were achieved using 15-50 MΩ microelectrodes filled with 3M KCl.
• Electrical potentials and resistances were measured, including dynamic changes in mucosal bathing solutions.

Main Results:

• Transepithelial potential was -4.9 ± 1.3 mV; apical cell membrane potential was -43.9 ± 0.6 mV; basolateral cell membrane potential was -48.8 ± 1.3 mV.
• Transepithelial resistance was 427 ± 66 Ω·cm², with an apical to basolateral resistance ratio of 3.4 ± 0.3.
• Individual resistances were: apical membrane 2,203 ± 585 Ω·cm², basolateral membrane 1,296 ± 384 Ω·cm², and shunt 604 ± 81 Ω·cm².

Conclusions:

• The shunt pathway accounts for approximately 85% of the transepithelial conductance in Necturus antral mucosa.
• This high shunt conductance indicates a significant role for the paracellular pathway in ion and water transport.
• The findings provide critical data for understanding Necturus gastric epithelial electrophysiology and transport mechanisms.