Permittis

Permittis is a term used in theoretical discussions of membrane physiology to denote the regulated permeability of a barrier to solutes. Unlike static measures of permeability, permittis emphasizes dynamic control: passage is permitted or restricted by an integration of transport proteins, lipid environment, and cellular signaling that tune the effective permeability in response to conditions.

Origin and usage: The word derives from Latin permittere, meaning to allow. In the literature, permittis appears in speculative models and in some teaching materials to highlight that permeability is not a fixed property but a condition that can be modulated.

Determinants: Structural porosity provided by channels and transporters; gating and trafficking of these proteins; membrane fluidity and lipid composition; electrochemical gradients; and regulatory signaling that alters protein activity. The outcome is a permeability coefficient that varies with stimuli such as voltage, ligands, temperature, and pH.

Contexts: Permittis is invoked in discussions of cell membranes, blood-brain barrier models, plant plasmodesmata, and synthetic membranes in biomimetic research. It is not an established technical term in mainstream physiology, where permeability is described by specific mechanisms or by the concept of a permeability coefficient P.

Relation to related concepts: It overlaps with permeability, selective transport, and permittivity in electromagnetism but remains distinct in its biological context. As a formal term, permittis remains largely confined to conceptual or teaching discussions rather than standardized nomenclature.