A REVIEW ON RECEPTORS

Abstract

A molecule that binds to a receptor is called a ligand, and can be a peptide or another small molecule such as a neurotransmitter, hormone, pharmaceutical drug, toxin, or parts of the outside of a virus or microbe. Regardless of the nature of the initiating signal, the cellular responses are determined by the presence of receptors that specifically bind the signaling molecules. Binding of signal molecules causes a conformational change in the receptor, which then triggers the subsequent signaling cascade. A large number of these receptors have been identified and are grouped into three families defined by the mechanism used to transduce signal binding into a cellular response. Categories of cellular receptors: Membrane-impermeant signaling molecules can bind to and activate either channel linked receptors, enzyme linked receptors, or G protein coupled receptors. Membrane permeant signaling molecules activate intracellular. The cholinergic receptors includes muscarinic and nicotinic receptors and also adnergic, histaminic, prostanoid, dopamine, opiod, imidazoline receptors used in the various activity in the body.