Cholinergic receptors structure-activity relationships

Thus, cholinergic receptor classification can be considered in terms of three stages of development. Initially, Dale [2] distinguished nicotinic and muscarinic receptor subtypes with crude alkaloids. Then, chemical synthesis and structure-activity relationships clearly revealed that nicotinic and muscarinic receptors were heterogeneous, but chemical selectivity could not come close to uncovering the true diversity of receptor subtypes. Lastly, analysis of subtypes came from molecular cloning, making possible the classification of receptors on the basis of primary structure (Fig. 11-2). 

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