Alpha-1A adrenergic receptor (Alpha-1L phenotype) (ADRA1A)

The Alpha-1A adrenergic receptor (Alpha-1L phenotype) is a distinct pharmacological state of the alpha-1A adrenoceptor, encoded by the ADRA1A gene, which exhibits a characteristically low affinity for the antagonist prazosin (Muramatsu et al., 2011, PMID: 21888571). It is the predominant receptor subtype responsible for mediating smooth muscle contraction in the human prostate, bladder neck, and urethra (IUPHAR/BPS Guide to Pharmacology). In the context of benign prostatic hyperplasia (BPH), overactivity or increased density of these receptors leads to lower urinary tract symptoms (LUTS) by obstructing urinary flow (Ford et al., 1997, PMID: 9129122). Therapeutic agents such as tamsulosin and silodosin target this receptor as antagonists to promote smooth muscle relaxation and improve voiding efficiency (StatPearls, "Alpha-1 Blockers"). Although it is not a separate genetic isoform, the Alpha-1L state is believed to result from the alpha-1A receptor's interaction with specific accessory proteins or distinct conformational arrangements (PubMed, PMID: 11792234). Consequently, it represents a major therapeutic target for improving quality of life in patients with urinary retention and prostate enlargement. Understanding the Alpha-1L phenotype is essential for developing uroselective drugs that minimize systemic side effects like hypotension. Research continues to investigate the exact molecular basis of this phenotype to refine drug selectivity.

Other names

Alpha-1L adrenoceptorAlpha-1L-ARAlpha-1A-AR (low affinity state)Alpha-1A/L-adrenoceptor

Antagonism of the alpha-1A adrenergic receptor, specifically targeting the Alpha-1L pharmacological phenotype to relax smooth muscle in the prostate and bladder neck.