Extracellular hydrogen ion concentration

Extracellular hydrogen ion concentration is a physicochemical property that measures the level of H⁺ ions in the extracellular fluid, which determines **extracellular pH**[7]. pH changes in extracellular fluids influence a multitude of biological processes, including the gating of ion channels and receptors, enzyme activity, and cell signaling[1]. Abnormal extracellular pH—such as acidosis or alkalosis—is implicated in multiple diseases. While not a molecular target itself, extracellular H⁺ can modulate the activity of other targets (e.g., GABA(A) receptors, ion channels) and is influenced indirectly by drugs that affect acid-base homeostasis[1][6]. It is maintained by active transporters and buffering systems but is not a receptor, enzyme, or transporter.

Other names

Extracellular pHHydrogen ion concentration (extracellular)[H⁺] (extracellular)

Indirect modulation via alteration of acid-base equilibrium: drugs can affect extracellular pH, which in turn modulates receptor and ion channel function[1][6].