Laboratory assessment of terazosin and alpha-1 blockade in prostatic hyperplasia.
The alpha-1 adrenergic innervation of the human prostate has been studied using radioligand receptor binding methods and in vitro contractile experiments. The density of alpha-1 adrenergic binding sites is of the same order of magnitude as alpha-2 adrenergic and muscarinic-cholinergic (MCh) receptors in the human prostate adenoma. The contractile response of human prostate adenomas to selective alpha-1, alpha-2, and MCh agonists indicated that smooth muscle contraction of the human prostate is mediated by alpha-1 adrenoceptors. The selective affinities of terazosin for alpha-1 and alpha-2 binding sites were determined using competitive displacement assays. Terazosin was shown to have a four hundred-fold greater affinity for alpha-1 binding sites. The concentration of terazosin-inhibiting phenylephrine-induced contractions suggested that terazosin inhibits prostate smooth muscle contraction via alpha-1 adrenoceptors.
Lepor
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Division of Urologic Surgery, Jewish Hospital of St. Louis, Missouri.
Gup
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Baumann
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Shapiro
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D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology*; D004311:Double-Blind Method; D006801:Humans; D008297:Male; D015337:Multicenter Studies as Topic; D009119:Muscle Contraction / Q000187:drug effects; D009130:Muscle, Smooth / Q000187:drug effects; D011224:Prazosin / Q000031:analogs & derivatives* / Q000494:pharmacology; D011467:Prostate / Q000294:innervation*; D011470:Prostatic Hyperplasia / Q000188:drug therapy* / Q000503:physiopathology; D011869:Radioligand Assay; D011897:Random Allocation; D011942:Receptors, Adrenergic, alpha / Q000187:drug effects / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D011942:Receptors, Adrenergic, alpha; C041226:Terazosin; D011224:Prazosin