Physiology of Non-Voltage-Gated Ion Channels  

¹ Physiology Department, Qena Faculty of Medicine - South Valley University

² Physiology Department, Faculty of Medicine - Al-Azhar University

^*Corresponding Author

Department of Physiology,

Faculty of Medicine, Al-Azhar University

Egypt

Tel:00201067970804

E-mail:Khaled_71111@yahoo.com

Abstract

Ion channels are transmembrane proteins that allow ions to flow across the cell membrane. They are characterized by selectivity. Physiological processes include excitation-contraction coupling, synaptic transmission, hormone secretion, and sensory transduction.

Ion channels can be classified according to the presence or absence of gates; open and gated channels. Members of gated channels are; voltage-gated, ligand-gated, and other gating mechanisms. Ion channels that open following a change in the membrane voltage potential are known as voltage-gated ion channels. Ligand-gated ion channels allow ions to flow across the pore in response to the binding of an external chemical messenger (ligand). They are divided into four families: cys-loop receptors, ionotropic glutamate receptors, ATP-gated P₂X receptors, and ligand-gated Ca²⁺ channels. Other gating includes activation/inactivation by second messengers from within of the cell membrane.  They include; transient receptor potential, cyclic nucleotide-gated channels, ATP sensitive K+ channels, calcium-activated K⁺ channels, mechanosensitive ion channels, acid-sensing ion channels, and cystic fibrosis transmembrane conductance regulator Cl^- channels. This review aims to show the physiological bases of ion channel functions. That is important in understanding the pathophysiology, and treatment of channelopathies.

Keywords: Ion Channels, Voltage-Gated, Ligand-Gated, Na⁺ Channels, K⁺ Channels, Ca²⁺ Channels

Download the full article (PDF)