TY - JOUR T1 - α<sub>1</sub>-Adrenergic Receptors: New Insights and Directions JF - Journal of Pharmacology and Experimental Therapeutics JO - J Pharmacol Exp Ther SP - 403 LP - 410 VL - 298 IS - 2 AU - Michael T. Piascik AU - Dianne M. Perez Y1 - 2001/08/01 UR - http://jpet.aspetjournals.org/content/298/2/403.abstract N2 - The adrenergic receptors play a key role in the modulation of sympathetic nervous system activity as well as a site of action for many therapeutic agents. The α1-adrenergic receptor subtypes (α1A-, α1B-, α1D) are the prime mediators of smooth muscle contraction and hypertrophic growth, but their characterization in both binding and function have lagged the other adrenergic family members. Although they are derived from a related ancestral gene and all nine adrenergic receptor family members bind the endogenous ligands, epinephrine and norepinephrine, with roughly similar affinities, there are major differences in the mode of binding, second messenger utilization, and physiological effects of the α1-subtypes compared with β- or α2-subtypes. Here, we review the recent literature on aspects of its binding pocket and how it differs from the β-adrenergic receptor paradigms. We also review the signaling components and aspects of its function and provide new insights into its roles in smooth muscle, growth, neurological, and cardiovascular function. The American Society for Pharmacology and Experimental Therapeutics ER -