SILODOSIN IS A SELECTIVE ANTAGONIST OF POST-SYNAPTIC ALPHA-1 ADRENORECEPTORS, WHICH ARE LOCATED IN THE HUMAN PROSTATE, BLADDER BASE, BLADDER NECK, PROSTATIC CAPSULE, AND PROSTATIC URETHRA. BLOCKADE OF THESE ALPHA-1 ADRENORECEPTORS CAN CAUSE SMOOTH MUSCLE IN THESE TISSUES TO RELAX, RESULTING IN AN IMPROVEMENT IN URINE FLOW AND A REDUCTION IN BPH SYMPTOMS.