Alpha-1A adrenoceptor (Alpha-1L phenotype) (ADRA1A)

The Alpha-1L adrenoceptor is a distinct pharmacological phenotype of the Alpha-1A adrenoceptor, which is encoded by the ADRA1A gene. Historically identified by its low affinity for the antagonist prazosin compared to the 'classical' Alpha-1A state, the Alpha-1L phenotype is the predominant functional receptor mediating smooth muscle contraction in the human prostate, bladder neck, and urethra. Its primary biological function involves the regulation of sympathetic nervous system-mediated muscle tone in the lower urinary tract via Gq-protein signaling and calcium mobilization. In the context of disease, overactivity or increased tone of these receptors contributes significantly to the obstructive symptoms of benign prostatic hyperplasia (BPH) and associated lower urinary tract symptoms (LUTS). Consequently, this receptor phenotype is a primary therapeutic target for urological drugs. Selective antagonists like tamsulosin and silodosin are designed to target the Alpha-1A/L receptors with high affinity to alleviate urinary obstruction while minimizing systemic side effects like hypotension, which are more common with non-selective alpha-1 blockers.

Other names

Alpha-1L adrenoceptorAlpha-1A adrenergic receptorADRA1AAlpha-1C adrenoceptoralpha1A-ARAlpha-1A/L adrenoceptor

Competitive antagonism of the alpha-1A adrenoceptor (specifically the alpha-1L pharmacological phenotype) to relax smooth muscle in the prostate and bladder neck.