We characterize the neuropharmacology and neurophysiology of the prostate. Thus far, we have characterized the alpha1, alpha2, muscarinic cholinergic, DHP, and endothelin receptors in the prostate using radioligand receptor-binding studies. Additionally, we determined the cellular localization and physiological role of these receptors using autoradiography, isometric tension studies, and in vivo studies. Recently, we characterized and localized the alpha1 adrenoceptor subtypes in the human prostate. The clinical relevance of these investigations relates to the management of benign prostatic hyperplasia (BPH), a very common disease that causes bladder dysfunction and lower urinary tract symptoms in the aging male population. Bladder outlet obstructions secondary to BPH appear to be an important factor in the pathophysiology of the disease process. Alpha1 antagonists are routinely used to treat BPH. The tension of prostate smooth muscle is mediated by the alpha1 endothelin receptors and nitric oxide. In future investigations, we will study the role of endothelin antagonists and nitric oxide agonists.