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Cell Biology JoVE (Open Access) Citable · DOI

Standardized Measurement of Nasal Membrane Transepithelial Potential Difference (NPD)

DOI: 10.3791/57006-v
What you'll learn
  • ✓ Perform standardized nasal potential difference (NPD) measurement in human subjects
  • ✓ Evaluate CFTR and ENaC ion channel function using transepithelial voltage
  • ✓ Interpret NPD tracings to distinguish cystic fibrosis from healthy phenotypes
  • ✓ Apply sequential perfusion protocol to assess epithelial ion transport
Protocol

Here, we present a standardized protocol to measure the nasal potential difference (NPD). Cystic fibrosis transmembrane conductance regulator (CFTR) and epithelial sodium channel (ENaC) function are evaluated by the change in the voltage across the nasal epithelium after superfusion of solutions that modify ion channel activity, providing an outcome measure.

Difficulty
advanced
Total time
~45–60 minutes per subject

Steps

1
Gather and prepare measurement materials

Assemble electrode apparatus, perfusion system, and electrolyte solutions required for nasal potential difference measurement. Verify equipment calibration and solution osmolarity.

▶ 01:01
2
Position measurement electrodes in nasal cavity

Insert reference and measuring electrodes through nasal passages into contact with nasal epithelial membrane. Ensure stable electrode placement and electrical connection before measurement.

▶ 02:19
3
Record basal potential difference baseline

Measure and document the baseline transepithelial voltage across the nasal epithelium under resting conditions without any pharmacological intervention.

▶ 04:35
4
Apply sequential perfusions and record NPD responses

Serially superfuse nasal epithelium with solutions modulating CFTR and ENaC activity (amiloride, isoproterenol, ATP). Record voltage changes after each perfusion to assess ion channel function.

▶ 06:02
5
Interpret NPD tracings and compare phenotypes

Analyze recorded voltage responses in CF versus healthy subjects. Characteristic NPD patterns indicate differences in CFTR-mediated chloride secretion and ENaC-dependent sodium reabsorption.

▶ 07:42
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