Adrenergic Receptor Protocols

Methods in Molecular Biology TM TM VOLUME 126 Adrenergic Receptor Protocols Edited by Curtis A. Machida HUMANA PRESS Library Construction 3 1 Construction of Libraries for Isolation of Adrenergic Receptor Genes Margaret A. Scofield, Jean D. Deupree, and David B. Bylund 1. Introduction 1.1. Adrenergic Receptors Adrenergic receptors mediate the central and peripheral actions of norepinephrine and epinephrine. Both of these catecholamine messengers play important roles in the regulation of diverse physiological systems and are widely distributed throughout the body. Agonists and antagonists interacting with adrenergic receptors have proven useful in the treatment of a variety of cardiovascular, respiratory, and mental disorders (1,2). Adrenergic receptors were originally divided into two major types, α-adrenergic receptor (α-AR) and β-adrenergic receptor (β-AR), based on their pharmacological characteristics (i.e., rank order potency of agonists) (3). Subsequently, the α-AR and β-AR types were further subdivided into α1-AR, α2-AR, β1-AR, and β2-AR subtypes (for a more complete historical perspective see refs. 4,5). Based on both pharmacological and molecular evidence, it is now clear that a more useful classification scheme is based on three major types—α1-AR, α2-AR, and β-AR—each of which is further divided into three or four subtypes (Fig. 1) (4). 1.1.1. α1-AR Subtypes α1A-AR and α1B-AR subtypes were defined pharmacologically based on the differential affinities of WB 4101 and phentolamine (6–8), and on selective