ION CHANNELS–SOME BASIC AND APPLIED ASPECTS

Patel SV*, Prajapati AB*, Dikshit RK**

ABSTRACT

Each of the hundred trillion cells in human body is enveloped by a biological membrane, which is known as plasma membrane.[1] This membrane separates the cellular fluid (i.e. intracellular fluid or cytosol) from the fluid surrounding the cells (i.e. extracellular fluid) or acts as a partition between sub-cellular organelles within the same cell. Such a biological membrane acts as a barrier for free passage of substances between the fluid compartments. However, this barrier is only partial. While lipid soluble substances can readily cross the membrane, water and water soluble molecules (e.g., ions, glucose, urea, etc) cannot do so. The partial nature of this membrane can be explained by its molecular structure.[2] Most of the membranes are composed of two layers of lipid with small amounts of embedded proteins (see fig. 1). These protein molecules form pores within the lipid bilayer and allow the movement of water soluble substances. It is actually these aqueous pores that are known as ―ion channels‖.[2] These channels allow the movement of charged particles i.e. ―ions‖ such as sodium (Na+), potassium (K+), calcium (Ca+), chloride (Cl-) etc across the plasma membrane.[3]

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