alpha1- and alpha2-adrenoceptors in BPH.
The dynamic obstruction of the bladder outlet secondary to benign prostatic hyperplasia (BPH), and the contractile properties of the human prostate are mediated primarily by alpha1-adrenoceptors. There are now at least three subtypes (A, B, and D) of alpha1-adrenoceptors, and recent work revealed that alpha1A-adrenoceptor and alpha1B-adrenoceptor may have a prime role for prostatic obstruction, and contraction of artery, respectively. Very recently, the presence of a low affinity alpha1-adrenoceptor for prazosin, named alpha1L, in the human BPH tissue has been determined. Because the DNA sequence of alpha1L-adrenoceptor has not yet been cloned, the alpha1L-adrenoceptor may be another form of the alpha1A-adrenoceptor, or another pharmacologically distinct alpha1-adrenoceptor which mediates the norepinephrine-induced contraction of the prostatic smooth muscle. Furthermore, the contribution of alpha1-adrenoceptors in the prostate to symptoms (not only obstructive, but irritative symptoms) which are elicited by prostatic obstruction remains to be determined.
Department of Urology, Niigata University School of Medicine, Niigara, Japan. takedama@med.niigata-u.ac.jp
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Takeda
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Hatano
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Arai
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Obara
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Tsutsui
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Takahashi
D000317:Adrenergic alpha-Antagonists / Q000627:therapeutic use; D006801:Humans; D008297:Male; D011470:Prostatic Hyperplasia / Q000188:drug therapy / Q000503:physiopathology*; D018340:Receptors, Adrenergic, alpha-1 / Q000145:classification / Q000502:physiology*; D018341:Receptors, Adrenergic, alpha-2 / Q000502:physiology*
D000317:Adrenergic alpha-Antagonists; D018340:Receptors, Adrenergic, alpha-1; D018341:Receptors, Adrenergic, alpha-2