Resting potential

Definition

The stable, negative electrical potential difference across the plasma membrane of a non-excited cell, maintained by differential ion concentrations and selective membrane permeability. In neurons and muscle fibers, this baseline polarization (typically −50 to −90 mV in arthropods) sets the electrochemical conditions required for generating action potentials upon stimulation.

Etymology

Example

In the giant axon of the American cockroach (Periplaneta americana), the resting potential of approximately −70 mV is established by high intracellular K⁺ and the Na⁺/K⁺-ATPase pump; depolarization beyond threshold triggers the voltage-gated sodium currents that propagate escape reflexes.

Synonyms

• resting membrane potential
• membrane resting potential

Related Terms

• Action potential
• graded potential
• depolarization
• hyperpolarization
• ion channel
• electrochemical gradient
• threshold potential

Usage Notes

Distinguished from dynamic potentials (action potentials, graded potentials) by its stability in the absence of stimulation. Values vary by cell type, temperature, and species; insect neurons often show more negative resting potentials than mammalian counterparts due to differences in ionic regulation and membrane composition.