Related Experiment Video
Updated: Jul 9, 2026

Double-barreled and Concentric Microelectrodes for Measurement of Extracellular Ion Signals in Brain Tissue
Published on: September 5, 2015
Ion pairing as a possible clue for discriminating between sodium and potassium in biological and other complex
Abstract:
For a series of biologically relevant anions, we present free energy changes upon replacing potassium with sodium in a contact ion pair. Calculations performed using a combination of molecular dynamics simulations and ab initio methods demonstrate the ordering of anions in a Hofmeister series. Small anionic groups such as carboxylates preferentially pair with sodium, while intermediate cases such as chloride or monovalent phosphate exhibit almost no specificity, and large anions (e.g., methylsulfonate) prefer potassium over sodium. These results can rationalize different behavior of Na+ versus K+ at the surface of hydrated proteins, DNA, and reversed micelles.
Related Concept Videos
Ionic Association
The Role of Ion Channels in Neuronal Computation
Sometimes a single EPSP is strong enough to induce an action potential in the postsynaptic neuron. However, multiple presynaptic inputs must often create EPSPs around the same time for the postsynaptic neuron to be sufficiently depolarized to fire an action potential.
Ionic Bonds
Primary Active Transport
Primary Active Transport
Pore Transport and Ion-Pair Transport
Pore transport, also known as convective transport, is a process where small molecules like urea, water, and sugars rapidly cross cell membranes as though there were channels or pores in the membrane. Although direct microscopic evidence is limited but the concept of pores or channels is widely accepted based on physiological evidence. Despite the lack of direct microscopic...

