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Drobnis EZ, Nangia AK. Cardiovascular/Pulmonary Medications and Male Reproduction. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2017; 1034:103-130. [PMID: 29256129 DOI: 10.1007/978-3-319-69535-8_9] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Cardiovascular and respiratory medications are used by men of reproductive age although use of the former is most prevalent in advanced age. Many of these drugs have been associated with sexual dysfunction, including erectile and ejaculatory dysfunction, but for most there is insufficient evidence to link their use with testicular dysfunction, reduced semen quality or infertility. Some exceptions are the irreversible α1-adrenergic antagonist phenoxybenzamine, which carries a high risk of retrograde ejaculation; the specific α1A-adrenergic antagonists silodosin and tamsulosin, used primarily to treat BPH/lower urinary tract symptoms, which can cause retrograde ejaculation; and the peripheral β1-adrenergic antagonist atenolol, used to treat hypertension, which may decrease testosterone/free-testosterone levels. In this chapter, we review the evidence available regarding adverse reactions on male reproduction of adrenergic receptor agonists/antagonists, calcium channel blockers, angiotensin converting enzyme (ACE) inhibitors, diuretics, digoxin, and hydralazine. For some of these medications, there is some evidence for male reproductive effects, along with some solid work in experimental and companion animal species suggesting negative effects. In contrast, and of special note, are calcium channel blockers, which have long been included on lists of medications with the potential to cause male infertility. This turns out to be a good example of a substance with profound effects on sperm function in vitro, but with limited evidence for in vivo effects on semen quality or fertility, even in experimental species. We hope that the evidence provided in this chapter will stimulate additional studies for these important classes of medications.
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Affiliation(s)
- Erma Z Drobnis
- Obstetrics, Gynecology and Women's Health, University of Missouri School of Medicine, Columbia, MO, USA
| | - Ajay K Nangia
- Department of Urology, University of Kansas Medical Center, Kansas City, KS, USA
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Suzuki T, Otsuka A, Matsumoto R, Furuse H, Ozono S. The expression of β3-adrenoceptors and their function in the human prostate. Prostate 2016; 76:163-71. [PMID: 26768278 DOI: 10.1002/pros.23108] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/16/2015] [Accepted: 09/21/2015] [Indexed: 11/12/2022]
Abstract
BACKGROUND Little is known about β3-adrenoceptor (AR) expression and function in human prostate. We examined the expression and distribution of β-AR subtypes in normal prostate and benign prostatic hyperplasia (BPH) tissues, and investigated which selective β-AR subtype agonist was most involved in the relaxation of isolated human prostate strips. METHODS Messenger RNA (mRNA) expression for β1-, β2-, and β3 -ARs was investigated using reverse transcriptase-polymerase chain reactions (RT-PCR). Quantitative analysis of mRNA expression of β-AR subtypes between normal prostate and BPH tissues was performed using quantitative RT-PCR (qPCR). Distributions were examined by immunohistochemistry (IHC). Strips of human normal prostate or BPH were suspended in organ baths and exposed to isoproterenol, dobutamine, procaterol, and TRK-380 to investigate their relaxant effects on KCl-induced contractions, and their inhibitory effects on electrical field stimulation (EFS)-induced contractions. RESULTS We confirmed the presence of mRNA for β1-, β2-, and β3-ARs both in normal prostate and in BPH tissues. For β3-AR, mRNA expression in BPH tissues was significantly higher than in normal prostate tissues, but there was no significant difference in β1- and β2-AR expression between normal and BPH tissues. IHC revealed differences in staining intensity between smooth muscle cells and glandular cells, with different proportions for different β-AR subtypes. Staining of β3-AR was particularly intense in smooth muscle cells as opposed to glandular cells. Isoproterenol and TRK-380 significantly decreased the tone of KCl-induced contractions of the normal prostate strips. The rank order of relaxant effects was isoproterenol > TRK-380 > procaterol > dobutamine. All selective β-AR agonists significantly decreased the amplitude of EFS-induced contractions of the normal prostate strips. The rank order of inhibitory effects was isoproterenol > dobutamine >TRK-380 > procaterol. In BPH strips, all selective β-AR agonists showed no significant relaxant or inhibitory effects on KCl- or EFS-induced contractions. CONCLUSIONS β3 -AR is abundant in human prostate smooth muscle, whose relaxation is mediated by β1- and β3-AR stimulation. β3-AR agonists may have clinical use in the treatment of male non-BPH patients or neurogenic bladder patients with voiding dysfunction.
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Affiliation(s)
- Takahisa Suzuki
- Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Atsushi Otsuka
- Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Rikiya Matsumoto
- Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Hiroshi Furuse
- Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan
| | - Seiichiro Ozono
- Department of Urology, Hamamatsu University School of Medicine, Hamamatsu, Japan
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Lam M, Mitsui R, Hashitani H. Electrical properties of purinergic transmission in smooth muscle of the guinea-pig prostate. Auton Neurosci 2016; 194:8-16. [DOI: 10.1016/j.autneu.2015.11.003] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2015] [Revised: 11/18/2015] [Accepted: 11/23/2015] [Indexed: 11/24/2022]
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White CW, Short JL, Ventura S. Rho kinase activation mediates adrenergic and cholinergic smooth muscle contractile responses in the mouse prostate gland. Eur J Pharmacol 2013; 721:313-21. [DOI: 10.1016/j.ejphar.2013.09.012] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2013] [Revised: 08/27/2013] [Accepted: 09/04/2013] [Indexed: 12/16/2022]
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White CW, Xie JH, Ventura S. Age-related changes in the innervation of the prostate gland: implications for prostate cancer initiation and progression. Organogenesis 2013; 9:206-15. [PMID: 23872639 PMCID: PMC3896592 DOI: 10.4161/org.24843] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The adult prostate gland grows and develops under hormonal control while its physiological functions are controlled by the autonomic nervous system. The prostate gland receives sympathetic input via the hypogastric nerve and parasympathetic input via the pelvic nerve. In addition, the hypogastric and pelvic nerves also provide sensory inputs to the gland. This review provides a summary of the innervation of the adult prostate gland and describes the changes which occur with age and disease. Growth and development of the prostate gland is age dependent as is the occurrence of both benign prostate disease and prostate cancer. In parallel, the activity and influence of both the sympathetic and parasympathetic nervous system changes with age. The influence of the sympathetic nervous system on benign prostatic hyperplasia is well documented and this review considers the possibility of a link between changes in autonomic innervation and prostate cancer progression.
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Affiliation(s)
- Carl W White
- Drug Discovery Biology; Monash Institute of Pharmaceutical Sciences; Monash University; Parkville, VIC Australia
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de Almeida Kiguti LR, Pupo AS. Investigation of the Effects of α1‐Adrenoceptor Antagonism and L‐Type Calcium Channel Blockade on Ejaculation and Vas Deferens and Seminal Vesicle Contractility In Vitro. J Sex Med 2012; 9:159-68. [DOI: 10.1111/j.1743-6109.2011.02410.x] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
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Ventura S, Oliver VL, White CW, Xie JH, Haynes JM, Exintaris B. Novel drug targets for the pharmacotherapy of benign prostatic hyperplasia (BPH). Br J Pharmacol 2011; 163:891-907. [PMID: 21410684 DOI: 10.1111/j.1476-5381.2011.01332.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Benign prostatic hyperplasia (BPH) is the major cause of lower urinary tract symptoms in men aged 50 or older. Symptoms are not normally life threatening, but often drastically affect the quality of life. The number of men seeking treatment for BPH is expected to grow in the next few years as a result of the ageing male population. Estimates of annual pharmaceutical sales of BPH therapies range from $US 3 to 10 billion, yet this market is dominated by two drug classes. Current drugs are only effective in treating mild to moderate symptoms, yet despite this, no emerging contenders appear to be on the horizon. This is remarkable given the increasing number of patients with severe symptoms who are required to undergo invasive and unpleasant surgery. This review provides a brief background on prostate function and the pathophysiology of BPH, followed by a brief description of BPH epidemiology, the burden it places on society, and the current surgical and pharmaceutical therapies. The recent literature on emerging contenders to current therapies and novel drug targets is then reviewed, focusing on drug targets which are able to relax prostatic smooth muscle in a similar way to the α(1) -adrenoceptor antagonists, as this appears to be the most effective mechanism of action. Other mechanisms which may be of benefit are also discussed. It is concluded that recent basic research has revealed a number of novel drug targets such as muscarinic receptor or P2X-purinoceptor antagonists, which have the potential to produce more effective and safer drug treatments.
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Affiliation(s)
- S Ventura
- Medicinal Chemistry and Drug Action, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Victoria, Australia.
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Abstract
α(1)-Adrenoceptors have been identified and characterized extensively by functional, radioligand-binding, and molecular biological techniques. Molecular clones have been isolated for three α(1)-subtypes (α(1a), α(1b), and α(1d)), and these subtypes are also functionally characterized. α(1)-Adrenoceptors are present in the prostate, urethra, bladder (urothelium, smooth muscle, and afferent nerves), ureter, vas deferens, peripheral ganglia, nerve terminals, vascular tissues, and central nervous system (CNS), and they could all potentially influence overall urinary function and contribute to both the therapeutic and adverse effects of α(1)-adrenoceptor antagonists in patients with benign prostatic hyperplasia (BPH) and lower urinary tract symptoms (LUTS). This review aimed to discuss the relevant physiological and pharmacological roles and molecular biology of α(1)-adrenoceptor subtypes in the prostate, urethra, bladder, ureter, and CNS.
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Roosen A, Blake-James BT, Wood D, Fry CH. Clinical and experimental aspects of Adreno-muscarinic synergy in the bladder base and prostate. Neurourol Urodyn 2010; 28:938-43. [PMID: 19618452 DOI: 10.1002/nau.20742] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
Recent clinical trials have shown that combination therapy using an alpha-receptor antagonist and an antimuscarinic is more effective than either agent alone in improving quality of life and objective urodynamic variables in men with bladder outflow obstruction. There appear to be no negative effects on bladder function. The mode of action of this combination is unknown but presumed to be an antimuscarinic reduction in detrusor overactivity and the alpha-receptor antagonist reduced outflow tract resistance. We have shown with in vitro experiments that in smooth muscles influencing outflow tract resistance (prostate, trigone) there is a profound contractile synergy between adrenergic and muscarinic pathways. We propose the hypothesis that both arms of the combination therapy reduce contractile tone of the outflow tract and that their simultaneous attenuation has a disproportionately large effect on outflow tract resistance. Our data from trigone muscle suggest that adrenergic and muscarinic receptor activation increase the intracellular [Ca(2+)] but the adrenergic pathway also operates through Ca(2+)-sensitisation of the contractile apparatus, primarily through a PKC-dependent pathway.
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Recio P, Orensanz LM, Martínez MP, Navarro-Dorado J, Bustamante S, García-Sacristán A, Prieto D, Hernández M. Noradrenergic vasoconstriction of pig prostatic small arteries. Naunyn Schmiedebergs Arch Pharmacol 2008; 376:397-406. [PMID: 18172615 DOI: 10.1007/s00210-007-0227-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2007] [Accepted: 11/17/2007] [Indexed: 11/29/2022]
Abstract
The current study investigated the distribution of adrenergic nerves and the action induced by noradrenaline (NA) in pig prostatic small arteries. Noradrenergic innervation was visualized using an antibody against dopamine-beta-hydroxylase (DBH), and the NA effect was studied in small arterial rings mounted in microvascular myographs for isometric force recordings. DBH-immunoreactive nerve fibers were located at the adventitia and the adventitia-media border of the vascular wall. Electrical field stimulation (EFS, 1-32 Hz) evoked frequency-dependent contractions that were reduced by guanethidine and prazosin (adrenergic neurotransmission and alpha1-adrenoceptors blockers, respectively) and by the alpha2-adrenoceptor agonist UK 14,304. The alpha2-adrenoceptor antagonist rauwolscine reversed the UK 14,304-produced inhibition. NA produced endothelium-independent contractions that were antagonized with low estimated affinities and Schild slopes different from unity by prazosin and the alpha1A-adrenoceptor antagonist N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-alpha-alpha-dimethyl-1H-indole-3-ethanamine (RS 17053). The alpha1A-adrenoceptor antagonist 5-methyl-3-[3-[4-[2-(2,2,2,-trifluoroethoxy) phenyl]-1-piperazinyl]propyl]-2,4-(1H)-pyrimidinedione (RS 100329), which also displays high affinity for alpha1L-adrenoceptors, and the alpha1L-adrenoceptor antagonist tamsulosin, which also has high affinity for alpha1A- and alpha1D-adrenoceptors, induced rightward shifts with high affinity of the contraction-response curve to NA. The alpha1D-adrenoceptor antagonist 8-[2-[4-(2-methoxyphenyl)-1-piperazinyl]-ethyl]8-azaspiro[4,5]decane-7,9-dione dihydrochloride (BMY 7378) failed to modify the NA contractions that were inhibited by extracellular Ca2+ removal and by voltage-activated (L-type) Ca2+ channel blockade. These data suggest that pig prostatic resistance arteries have a rich noradrenergic innervation; and NA, whose release is modulated by prejunctional alpha2-adrenoceptors, evokes contraction mainly through activation of muscle alpha1L-adrenoceptors coupled to extracellular Ca2+ entry via voltage (L-type)- and non-voltage-activated Ca2+ channels.
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Affiliation(s)
- Paz Recio
- Departamento de Fisiología (Fisiología Animal), Facultad de Farmacia, Universidad Complutense de Madrid, 28040 Madrid, Spain
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Sanbe A, Tanaka Y, Fujiwara Y, Tsumura H, Yamauchi J, Cotecchia S, Koike K, Tsujimoto G, Tanoue A. Alpha1-adrenoceptors are required for normal male sexual function. Br J Pharmacol 2007; 152:332-40. [PMID: 17603545 PMCID: PMC2042949 DOI: 10.1038/sj.bjp.0707366] [Citation(s) in RCA: 65] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
BACKGROUND AND PURPOSE Alpha(1)-adrenoceptor antagonists are extensively used in the treatment of hypertension and lower urinary tract symptoms associated with benign prostatic hyperplasia. Among the side effects, ejaculatory dysfunction occurs more frequently with drugs that are relatively selective for alpha(1A)-adrenoceptors compared with other drugs of this class. This suggests that alpha(1A)-adrenoceptors may contribute to ejaculation. However, this has not been studied at the molecular level. EXPERIMENTAL APPROACH The physiological contribution of each alpha(1)-adrenoceptor subtype was characterized using alpha(1)-adrenoceptor subtype-selective knockout (KO) mice (alpha(1A)-, alpha(1B)- and alpha(1D)-AR KO mice) since the subtype-specific drugs available are only moderately selective. We analysed the role of alpha(1)-adrenoceptors in the blood pressure and vascular response as well as ejaculation by determining these variables in alpha(1)-adrenoceptor subtype-selective KO mice and in mice with all their alpha(1)-adrenoceptor subtypes deleted (alpha(1)-AR triple-KO mice). KEY RESULTS The pregnancy rate was reduced by 50% in alpha(1A)-adrenoceptor KO mice, and this reduction was dramatically enhanced in alpha(1)-adrenoceptor triple-KO mice. Contractile tension of the vas deferens in response to noradrenaline was markedly decreased in alpha(1A)-adrenoceptor KO mice, and this contraction was completely abolished in alpha(1)-adrenoceptor triple-KO mice. This attenuation of contractility was also observed in the electrically stimulated vas deferens. CONCLUSIONS AND IMPLICATIONS These results demonstrate that alpha(1)-adrenoceptors, particularly alpha(1A)-adrenoceptors, are required for normal contractility of the vas deferens and consequent sperm ejaculation as well as having a function in fertility.
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Affiliation(s)
- A Sanbe
- Department of Pharmacology, National Research Institute for Child Health and Development, Setagaya-ku, Tokyo, Japan.
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Haynes JM. beta(2) and beta(3)-adrenoceptor inhibition of alpha(1)-adrenoceptor-stimulated Ca(2+) elevation in human cultured prostatic stromal cells. Eur J Pharmacol 2007; 570:18-26. [PMID: 17617401 DOI: 10.1016/j.ejphar.2007.05.035] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2006] [Revised: 05/18/2007] [Accepted: 05/22/2007] [Indexed: 11/15/2022]
Abstract
Prostatic beta-adrenoceptors inhibit alpha(1)-adrenoceptor-stimulated contractility. This study examines the effects of beta-adrenoceptor stimulation upon phenylephrine-induced elevations of intracellular Ca(2+)([Ca(2+)](i)) in human cultured prostatic stromal cells, and contractility of human prostatic tissue. Human cultured prostatic stromal cells were used for [(3)H]-cAMP accumulation studies or were loaded with 5-oxazolecarboxylic acid, 2-(6-(bis(2-((acetyloxy)methoxy)-2-oxoethyl)amino)-5-(2-(2-(bis(2-((acetyloxy)methoxy)-2-oxoethyl)amino)-5-methylphenoxy)ethoxy)-2-benzofuranyl)-, (acetyloxy)methyl ester (FURA-2AM, 10 microM) for Ca(2+) imaging studies. The beta-adrenoceptor agonist isoprenaline increased the accumulation of [(3)H]-cAMP (pEC(50)+/-S.E.M. 6.58+/-0.11) in human cultured prostatic stromal cells, an effect antagonized by the beta(2)-adrenoceptor antagonist (+/-)-1-[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxy]-3-[(1-methylethyl)amino]-2-butanol (ICI 118,551), but not by the beta(1)-adrenoceptor antagonist, atenolol. Isoprenaline (3 microM), the adenylyl cyclase activator, forskolin (20 microM) and the phosphodiesterase-4 inhibitor, rolipram (10 microM) inhibited the elevation of [Ca(2+)](i) elicited by phenylephrine (20 microM). The effect of isoprenaline could be blocked by ICI 118,551 (100 nM), the adenylyl cyclase inhibitor cis-N-(2-phenylcyclopentyl)-azacyclotridec-1-en-2-amine (MDL 12,330A, 20 microM) and the K(Ca) channel blocker, iberiotoxin (100 nM), but not by atenolol (1 microM) or the K(ATP) channel blocker, glibenclamide (3 microM). Agonists selective for beta(1)-(xamoterol and prenalterol), beta(2)-(procaterol and salbutamol) and beta(3)-((+/-)-(R(*), R(*))-[4-[2-[[2-(3-chlorophenyl)-2-hydroxyethyl]amino]propyl]phenoxy]acetic acid, BRL37344) adrenoceptors inhibited the elevation of [Ca(2+)](i) elicited by phenylephrine (20 microM) with a rank order of BRL37344> or =xamoterol> or =isoprenaline>procaterol> or =prenalterol>salbutamol. The xamoterol effect was reversed by ICI 118,551 (100 nM), but not by 1-(2-ethylphenoxy)-3-[[(1S)-1,2,3,4-tetrahydro-1-naphthalenyl]amino]-(2S)-2-propanol (SR59230A, 100 nM) or atenolol (1 microM). The BRL37344 effect was reversed by SR59230A (100 nM), but not by atenolol (1 microM) or ICI 118,551 (100 nM). Both xamoterol and BRL37344 inhibited phenylephrine-induced tissue contractility. This study shows that both xamoterol and BRL37344 are effective inhibitors of phenylephrine-induced effects in human cultured prostatic stromal cells and in prostatic tissue.
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Affiliation(s)
- John M Haynes
- Prostate Research Cooperative, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
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Michel MC, Vrydag W. Alpha1-, alpha2- and beta-adrenoceptors in the urinary bladder, urethra and prostate. Br J Pharmacol 2006; 147 Suppl 2:S88-119. [PMID: 16465187 PMCID: PMC1751487 DOI: 10.1038/sj.bjp.0706619] [Citation(s) in RCA: 338] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1 We have systematically reviewed the presence, functional responses and regulation of alpha(1)-, alpha(2)- and beta-adrenoceptors in the bladder, urethra and prostate, with special emphasis on human tissues and receptor subtypes. 2 Alpha(1)-adrenoceptors are only poorly expressed and play a limited functional role in the detrusor. Alpha(1)-adrenoceptors, particularly their alpha(1A)-subtype, show a more pronounced expression and promote contraction of the bladder neck, urethra and prostate to enhance bladder outlet resistance, particularly in elderly men with enlarged prostates. Alpha(1)-adrenoceptor agonists are important in the treatment of symptoms of benign prostatic hyperplasia, but their beneficial effects may involve receptors within and outside the prostate. 3 Alpha(2)-adrenoceptors, mainly their alpha(2A)-subtype, are expressed in bladder, urethra and prostate. They mediate pre-junctional inhibition of neurotransmitter release and also a weak contractile effect in the urethra of some species, but not humans. Their overall post-junctional function in the lower urinary tract remains largely unclear. 4 Beta-adrenoceptors mediate relaxation of smooth muscle in the bladder, urethra and prostate. The available tools have limited the unequivocal identification of receptor subtypes at the protein and functional levels, but it appears that the beta(3)- and beta(2)-subtypes are important in the human bladder and urethra, respectively. Beta(3)-adrenoceptor agonists are promising drug candidates for the treatment of the overactive bladder. 5 We propose that the overall function of adrenoceptors in the lower urinary tract is to promote urinary continence. Further elucidation of the functional roles of their subtypes will help a better understanding of voiding dysfunction and its treatment.
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MESH Headings
- Adrenergic Agonists/pharmacology
- Animals
- Gene Expression Regulation
- Humans
- Male
- Muscle Contraction
- Muscle, Smooth/metabolism
- Prostate/drug effects
- Prostate/metabolism
- Receptors, Adrenergic/drug effects
- Receptors, Adrenergic/genetics
- Receptors, Adrenergic/metabolism
- Receptors, Adrenergic, alpha-1/metabolism
- Receptors, Adrenergic, alpha-2/metabolism
- Receptors, Adrenergic, beta/metabolism
- Urethra/drug effects
- Urethra/metabolism
- Urinary Bladder/drug effects
- Urinary Bladder/metabolism
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Affiliation(s)
- Martin C Michel
- Department of Pharmacology & Pharmacotherapy, Academic Medical Centre, University of Amsterdam, Amsterdam, The Netherlands.
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Haynes JM, Cook ALM. Protein kinase G-induced activation of K(ATP) channels reduces contractility of human prostate tissue. Prostate 2006; 66:377-85. [PMID: 16302263 DOI: 10.1002/pros.20355] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
BACKGROUND Human cultured prostatic stromal cells respond to protein kinase G (PKG) activators and the nitric oxide donor, sodium nitroprusside (SNP) by opening ATP-sensitive potassium channels (K(ATP) channels) to reduce nifedipine-sensitive phorbol ester-induced contractility. METHODS PKG activators, SNP, diazoxide, nifedipine, isoprenaline, forskolin, and Sp-8-Br-cAMP were used to inhibit alpha(1)-adrenoceptor-induced contractions in tissue from transurethral resections of the prostate (TURP). The selective K(ATP) and large conductance Ca(2+) activated K(+) (BK(Ca)) channel inhibitors, glibenclamide and charybdotoxin, respectively were used to inhibit responses to PKG activators. RT-PCR identified the K(ATP) channel subunits present in TURP tissue and cultured cells. RESULTS The PKG activators, APT-cGMP (1 nM-100 microM) and PET-cGMP (1 nM-100 microM), and also SNP (1 nM-100 microM), forskolin (10 microM), diazoxide (100 microM) and nifedipine (3 microM) inhibited phenylephrine (20 microM)-induced contractions. The effect of APT-cGMP (1 nM-100 microM) could be reversed by glibenclamide, but not by charybdotoxin. TURP tissue contained mRNA for PKG Ialpha, Ibeta, and II and the K(ATP) channel subunits Kir6.1, Kir6.2, SUR2B, and SUR1. Cultured stromal cells contained only Kir6.1 and SUR2B subunit mRNA. SUR1 mRNA was detected in one of five cultured epithelial cell lines. CONCLUSIONS PKG activators reduce alpha(1)-adrenoceptor-induced contractility in TURP tissue via the activation of K(ATP) channels. (c) 2005 Wiley-Liss, Inc.
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Affiliation(s)
- John M Haynes
- The Prostate Research Co-Operative, Victorian College of Pharmacy, Monash University, Victoria, Australia.
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Hieble JP, Ruffolo RR. Recent advances in the identification of a 1- and a 2-adrenoceptor subtypes: therapeutic implications. Expert Opin Investig Drugs 2005; 6:367-87. [PMID: 15989605 DOI: 10.1517/13543784.6.4.367] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
The cloning of multiple subtypes of both alpha1- and alpha2-adrenoceptors has renewed interest in the therapeutic application of agents interacting with these receptors. Effort has primarily been directed towards the design of uroselective alpha1-adrenoceptor antagonists for the treatment of benign prostatic hyperplasia (BPH). Evidence is accumulating for the involvement of a novel alpha1-adrenoceptor, designated as alpha1L-adrenoceptor, in alpha1-adrenoceptor-mediated smooth muscle contraction in prostatic and other urogenital tissues. While several antagonists showing a high degree of uroselectivity in animal models have been identified, their clinical superiority over the currently available alpha1-adrenoceptor antagonists has not yet been demonstrated. It is possible that the interaction with alpha1-adrenoceptors, as yet uncharacterised subtypes, at non-prostatic sites contributes to the therapeutic activity of this drug class in BPH. The alpha1-adrenoceptor subtypes involved in the control of vascular tone are currently being evaluated, and the profile of interaction with the various alpha1-adrenoceptor subtypes may play a key role in the efficacy of cardiovascular drugs such as carvedilol. Alpha2-adrenoceptor agonists are now being employed for a variety of therapeutic applications, most involving actions on receptors within the central nervous system (CNS). These agents are useful in the treatment of hypertension, glaucoma, opiate withdrawal and attention deficit hyperactivity disorder (ADHD), and as analgesics and adjuncts to general anaesthesia. While subtype selectivity has not yet been applied to the design of new alpha2-adrenoceptor agonists for these applications, recent gene mutation/knock-out experiments have identified the alpha2-subtypes involved in some of these actions, and optimisation of a therapeutic profile may be possible. Furthermore, the design of agents combining affinities for multiple adrenoceptor subtypes, or the combination of a specific adrenoceptor affinity profile with another pharmacological action, may offer advantages over molecules selective for an individual adrenoceptor subtype.
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Affiliation(s)
- J P Hieble
- Division of Pharmacological Sciences, SmithKline Beecham Pharmaceuticals, 709 Swedeland Road, King of Prussia, PA 19406, USA
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Buljubasich R, Ventura S. Adenosine 5'-triphosphate and noradrenaline are excitatory cotransmitters to the fibromuscular stroma of the guinea pig prostate gland. Eur J Pharmacol 2005; 499:335-44. [PMID: 15381056 DOI: 10.1016/j.ejphar.2004.07.080] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2004] [Revised: 07/01/2004] [Accepted: 07/06/2004] [Indexed: 10/26/2022]
Abstract
Immunohistochemical studies demonstrated abundant P2X(1)-receptor immunoreactivity colocalized with alpha-actin within the fibromuscular stroma of the guinea pig prostate. P2X(2)-, P2X(3)- and P2X(4)-receptor immunoreactivity was absent. alphabetamethylene Adenosine 5'-triphosphate (ATP) attenuated contractile responses to electrical field stimulation (50 V, 0.5 ms, 5-20 Hz) in the absence and presence of prazosin (0.3 microM). Responses to 1-2 Hz were unaffected. ARL 67156 (6-N, N-diethyl-beta-gamma-dibromomethylene-D-adenosine-5-triphosphate; 100 microM) enhanced contractile responses to electrical field stimulation (50 V, 0.5 ms, 10-20 Hz). Concentration-response curves to exogenously applied ATP analogues on unstimulated preparations elicited concentration-dependent suramin (100 microM)-sensitive contractions. The rank order of potency was: alphabetamethylene ATP>2methylthio ATP=betagammamethylene ATP>adenosine 5'-diphosphate (ADP)=ATP. Adenosine and adenosine 5'-monophosphate (AMP) did not produce contractile responses. These results demonstrate the presence of functional P2X(1)-receptors within the fibromuscular stroma of the guinea pig prostate and suggest a cotransmitter role for ATP with noradrenaline during high-frequency stimulation.
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Affiliation(s)
- Rosanda Buljubasich
- Department of Pharmaceutical Biology and Pharmacology, Victorian College of Pharmacy, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
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Gray KT, Ventura S. Evaluation of the mouse prostate as a suitable model for the study of human prostate function. J Pharmacol Toxicol Methods 2005; 51:41-50. [PMID: 15596113 DOI: 10.1016/j.vascn.2004.07.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2004] [Accepted: 07/02/2004] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Research into prostate development and function is mainly carried out in rats and guinea pigs. While these animals have proven to be good models of human prostate function, their use is limited when compared with what could be achieved using the various currently available gene knockout mice. This study aimed to ascertain whether the mouse prostate was a viable model for studying human prostate function. METHODS Sections from mouse prostate glands were histochemically processed to visualise the neurotransmitters and receptors present. Isolated organ bath studies were conducted in Krebs-Henseleit solution at 37 degrees C to delineate the physiological mechanisms involved in contractility. RESULTS Positive histochemical staining for noradrenaline and acetylcholinesterase (AChE) was observed in the fibromuscular stroma. AChE-positive staining was also observed in epithelial cells lining prostatic acini. Immunoreactivity to P2X(1) and P2X(7) purinoceptors was observed in the fibromuscular stroma and immunoreactivity to P2X(4) purinoceptors in the glandular epithelium. Positive immunostaining for neuropeptide Y, big endothelin, calcitonin gene-related peptide (CGRP), substance P, and neurokinin A was observed in the fibromuscular stroma. Frequency-response curves (1.0 ms pulse duration, 60 V, 0.1-20 Hz) to electrical field stimulation yielded frequency-dependent contractions that were attenuated by tetrodotoxin (P < .001), guanethidine (P < .001), and prazosin (P = .01). Suramin (P = .21), alpha,beta-methylene ATP (P = .84), and atropine (P = .76) caused no significant effects. Concentration-response curves to endogenously administered phenylephrine yielded concentration-dependent contractions (pEC(50) = 6.1 +/- 0.3, maximum response 0.20 +/- 0.03 g), which were attenuated by prazosin (P < .001). DISCUSSION Histochemistry suggests that mouse prostates have a similar innervation to that of humans and other laboratory animals. Furthermore, responses to nerve stimulation are noradrenergic and mediated by alpha(1)-adrenoceptors. Therefore, the mouse prostate is a suitable model for human prostate function and a viable isolated preparation for contractility studies.
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MESH Headings
- Acetylcholinesterase/metabolism
- Adrenergic alpha-Agonists/pharmacology
- Animals
- Disease Models, Animal
- Dose-Response Relationship, Drug
- Electric Stimulation
- Feasibility Studies
- Guanethidine/pharmacology
- Humans
- Immunohistochemistry
- Isometric Contraction/drug effects
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Inbred Strains
- Muscle, Smooth/drug effects
- Muscle, Smooth/innervation
- Muscle, Smooth/metabolism
- Muscle, Smooth/physiology
- Neurotransmitter Agents/metabolism
- Norepinephrine/metabolism
- Perfusion
- Phenylephrine/pharmacology
- Prazosin/pharmacology
- Prostate/innervation
- Prostate/metabolism
- Prostate/physiology
- Receptors, Neurotransmitter/metabolism
- Receptors, Purinergic P2/metabolism
- Tetrodotoxin/pharmacology
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Affiliation(s)
- Katherine T Gray
- Department of Pharmaceutical Biology and Pharmacology, Faculty of Pharmacy, Monash University, 381 Royal Parade, Parkville, Victoria 3052, Australia
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Thiyagarajan M, Kaul CL, Ramarao P. Enhancement of alpha-adrenoceptor-mediated responses in prostate of testosterone-treated rat. Eur J Pharmacol 2002; 453:335-44. [PMID: 12398922 DOI: 10.1016/s0014-2999(02)02452-4] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study was undertaken to investigate the effect of testosterone on the alpha-adrenoceptor-mediated contractile responses in ventral lobe of rat prostate. Contractile responses to various alpha-adrenoceptor agonists (phenylephrine, A61603 (N-[5-(4,5-dihydro-1H-imidazol-2-yl)-2-hydroxy-5,6,7,8-tetrahydronaphthalen-1-yl] methanesulphonamide), clonidine, guanfacine, ST587 ((2,3-dihydro-benzo[1,4]dioxin-2-ylmethyl)-[2-(2,6-dimethoxy-phenoxy)-ethyl]-amine) and xylazine) were tested in prostate strips obtained from control and testosterone (3 mg/kg, s.c. 5 days a week for 15 days-10 doses total)-treated rats. Dose-response curves for alpha-adrenoceptor agonists in testosterone-treated animals showed a leftward shift, indicating increased sensitivity of tissue to alpha-adrenoceptor agonists. To find the mechanism of increased sensitivity, K(A) value and receptor reserve of phenylephrine were estimated. Neither the K(A) value nor the receptor reserve of phenylephrine was altered in testosterone-treated rats. The concentration-occupancy curve for A61603 was shifted leftward and the K(A) value for A61603 decreased about four-fold. The K(B) value of 2-(2,6-dimethoxyphenoxyethyl) aminomethyl-1,4-benzodioxane (WB4101) was not altered, however, the K(B) value for prazosin was decreased approximately 5.5-fold. These findings indicate that the testosterone-mediated increase in sensitivity of prostate to alpha-adrenoceptor agonists is due to alterations in the alpha(1)-adrenoceptor pool.
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Affiliation(s)
- Meenakshisundaram Thiyagarajan
- Department of Pharmacology and Toxicology, National Institute of Pharmaceutical Education and Research, Phase-10, SAS Nagar, Sector-67, Mohali, Punjab-160 062, India
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Chueh SC, Chern JW, Choong CM, Guh JH, Teng CM. Characterization of some novel alpha 1-adrenoceptor antagonists in human hyperplastic prostate. Eur J Pharmacol 2002; 445:125-31. [PMID: 12065203 DOI: 10.1016/s0014-2999(02)01717-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We synthesized some quinazoline-based compounds, such as FH-71 (ethyl 4-(3-(4-(2-methoxyphenyl)piperazinyl)aminoquinazolin-2-carboxylate), EW-65 (4-(3-(4-(2-methoxyphenyl)piperazinyl)propyl)aminoquinazolin-2-carboxamide) and EW-154 (2-(4-(4-(2-methoxyphenyl)piperazinyl)butyl)amino-4-cyclohexylamino-quinazolin), and then characterized their pharmacological properties in several tissues. All of these compounds produced potent inhibition of phenylephrine but not high K(+) or U46619 (11 alpha,9 alpha-epoxymethano-15S-hydroxy-prosta-5Z,13E-dienoic acid)-induced contractions in rat aorta, suggesting alpha(1)-adrenoceptor antagonist properties. With rat vasa deferentia and spleens as the functional alpha(1A)- and alpha(1B)-adrenoceptor models, respectively, FH-71 exhibited greater antagonistic potency in rat vas deferens, EW-154 in rat spleen, and EW-65 had similar effects in both tissues. The potency ratios of terazosin, FH-71, EW-65 and EW-154 against phenylephrine-induced contractions in rat vas deferens/spleen were 1, 19.04, 0.39 and 0.09, respectively. The results suggest that FH-71 is a selective alpha(1A)-adrenoceptor antagonist, whereas EW-154 exhibits more antagonistic selectivity against alpha(1B)-adrenoceptors. FH-71 also showed a greater potency than EW-65 and EW-154 against phenylephrine-induced contraction in human hyperplastic prostate. The pA(2) values were 8.34, 7.44 and 7.05, respectively. Furthermore, FH-71 and EW-65 were not cytotoxic whereas EW-154 (all in 10 microM) had a massive toxic effect (more than 80%) in human prostatic smooth muscle cells. These data show FH-71 to be a potent and selective alpha(1A)-adrenoceptor antagonist with activity in human hyperplastic prostate.
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Affiliation(s)
- Shih-Chieh Chueh
- Department of Urology, College of Medicine, National Taiwan University, No. 1, Jen-Ai Road, Sect. 1, Taipei, Taiwan
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Michel MC, Schafers RF, Goepel M. Alpha-blockers and lower urinary tract function: more than smooth muscle relaxation? BJU Int 2000; 86 Suppl 2:23-8; discussion 28-30. [PMID: 11501614 DOI: 10.1046/j.1464-410x.2000.00094.x] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Affiliation(s)
- M C Michel
- Department of Medicine, University of Essen, Germany.
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Pennefather JN, Lau WA, Mitchelson F, Ventura S. The autonomic and sensory innervation of the smooth muscle of the prostate gland: a review of pharmacological and histological studies. JOURNAL OF AUTONOMIC PHARMACOLOGY 2000; 20:193-206. [PMID: 11260358 DOI: 10.1046/j.1365-2680.2000.00195.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. We review literature demonstrating (a) the presence and (b) the actions of substances that mediate or modify neuroeffector transmission to the smooth muscle of the prostrate stroma of a number of species including man. 2. In all species studied prostatic stroma, but not secretory acini, receives rich noradrenergic innervation. Stimulation of these nerves causes contractions of prostate smooth muscle that are inhibited by guanethidine and by alpha1-adrenoceptor antagonists that probably act at the alpha1L-adrenoceptor. Such actions underlie the clinical use of alpha1-adrenoceptor antagonists in benign prostatic hyperplasia (BPH). 3. Acetylcholinesterase-positive nerves innervate prostatic stroma as well as epithelium. Atropine reduces nerve-mediated contractions of stromal muscle in the rat, guinea-pig and rabbit. M1, M2 and M3 muscarinic receptors have been implicated in eliciting or facilitating contraction in the prostate from guinea-pig, dog and rat, respectively. 4. Adenine nucleotides and nucleosides, nitric oxide (NO), opioids, neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP) may act as co-transmitters or modulators in autonomic effector nerves supplying prostate stroma. Adenosine inhibits neurotransmission to the rat prostate, and NO is inhibitory in prostate from human, rat, rabbit, pig and dog. The activity of peptides present in the relatively sparse sensory innervation of the prostate exhibits species variation, but, when effective, calcitonin gene-related peptide is inhibitory while tachykinins are stimulant. The roles of NPY and VIP in modulating stromal contractility remain unclear. 5. Taken together the current literature indicates that, in addition to noradrenaline, other neurotransmitters and neuromodulators may regulate the tone of prostatic smooth muscle. Whether drugs that mimic or modify their actions might be useful in providing symptomatic relief of the urinary symptoms associated with BPH remains to be established.
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Affiliation(s)
- J N Pennefather
- Department of Pharmacology, Monash University, Vic, Australia
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MURATA SATOSHI, TANIGUCHI TAKANOBU, TAKAHASHI MASAHIKO, OKADA KENICHIRO, AKIYAMA KATSUYOSHI, MURAMATSU IKUNOBU. TISSUE SELECTIVITY OF KMD-3213, AN α
1
-ADRENOCEPTOR ANTAGONIST, IN HUMAN PROSTATE AND VASCULATURE. J Urol 2000. [DOI: 10.1016/s0022-5347(05)67426-5] [Citation(s) in RCA: 61] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- SATOSHI MURATA
- From the Departments of Pharmacology and Urology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, and the Pharmacology Research Laboratory, Kissei Pharmaceutical Co., Ltd., Hotaka, Nagano, Japan
| | - TAKANOBU TANIGUCHI
- From the Departments of Pharmacology and Urology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, and the Pharmacology Research Laboratory, Kissei Pharmaceutical Co., Ltd., Hotaka, Nagano, Japan
| | - MASAHIKO TAKAHASHI
- From the Departments of Pharmacology and Urology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, and the Pharmacology Research Laboratory, Kissei Pharmaceutical Co., Ltd., Hotaka, Nagano, Japan
| | - KENICHIRO OKADA
- From the Departments of Pharmacology and Urology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, and the Pharmacology Research Laboratory, Kissei Pharmaceutical Co., Ltd., Hotaka, Nagano, Japan
| | - KATSUYOSHI AKIYAMA
- From the Departments of Pharmacology and Urology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, and the Pharmacology Research Laboratory, Kissei Pharmaceutical Co., Ltd., Hotaka, Nagano, Japan
| | - IKUNOBU MURAMATSU
- From the Departments of Pharmacology and Urology, School of Medicine, Fukui Medical University, Matsuoka, Fukui, and the Pharmacology Research Laboratory, Kissei Pharmaceutical Co., Ltd., Hotaka, Nagano, Japan
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Pennefather JN, Lau WA, Chin C, Story ME, Ventura S. alpha(1L)-adrenoceptors mediate noradrenaline-induced contractions of the guinea-pig prostate stroma. Eur J Pharmacol 1999; 384:25-30. [PMID: 10611415 DOI: 10.1016/s0014-2999(99)00667-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
The alpha(1)-adrenoceptor subtype mediating noradrenaline-induced contractions of the guinea-pig isolated prostatic smooth muscle was investigated. Noradrenaline produced concentration-dependent contractions of the tissue with a mean pD(2) value of 5.26+/-0.03 (n=20). These contractions were antagonised by prazosin, 2-(2, 6-dimethoxyphenoxyethyl)aminomethyl-1,4-benzodioxane hydrochloride (WB-4101), N-[2-(2-cyclopropylmethoxyphenoxy)ethyl]-5-chloro-alpha, alpha-dimethyl-1H-indole-3-ethanamine hydrochloride (RS-17053) and (R)-5-[2-[[2-(2-ethoxyphenoxy)ethyl]amino]-2-methylethyl]-2- methoxybenzensulfonamide methanesulphonate hydrate (tamsulosin). Mean pA(2) or apparent pK(B) estimates for the antagonism of noradrenaline were 8.15+/-0.05 for prazosin; 8.83+/-0.11 for WB-4101, 7.18+/-0.14 for RS-17053 and 10.11+/-0.12 for tamsulosin. The relatively low estimates of the apparent dissociation constant for all antagonists except tamsulosin indicate that an alpha(1L)-adrenoceptor mediates noradrenaline-induced prostatic smooth muscle contraction in the guinea-pig prostate gland.
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Affiliation(s)
- J N Pennefather
- Department of Pharmacology, Monash University, Wellington Road, Clayton, Victoria 3168, Australia
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Guh JH, Hsieh CH, Teng CM. Investigation of the effects of some alkaloidal alpha1-adrenoceptor antagonists on human hyperplastic prostate. Eur J Pharmacol 1999; 374:503-10. [PMID: 10422796 DOI: 10.1016/s0014-2999(99)00352-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
The effects of N-allylsecoboldine, (-)-discretamine, ( )-govadine and [(+/-)-2,3,10,11-tetrahydroxytetrahydroproto-berberine HBr] ((+/-)-THP) on contractile responses were investigated in human hyperplastic prostate. They all inhibited, concentration dependently, the tension responses to phenylephrine and electrical field stimulation, and the pA2 and pIC50 values were calculated. The relative potencies of these four agents with reference to prazosin were obtained. The results showed that N-allylsecoboldine exhibited greater potency (4.1-fold), whereas (-)-discretamine, (+/-)-govadine and (+/-)-THP had similar potencies, against contractions elicited by electrical field stimulation and against contractions elicited by phenylephrine in human hyperplastic prostate. In addition, the potency ratios of N-allylsecoboldine, (-)-discretamine, (+/-)-govadine and (+/-)-THP against phenylephrine-induced contractions in rat vas deferens/spleen were 7.78, 0.89, 0.57, and 0.96, respectively. In the presence of prazosin (0.3 +/-M) to block alpha1-adrenoceptor-mediated responses, nifedipine (10 microM), but not the above four agents, significantly blocked KCl (60 mM)-induced tension responses in human hyperplastic prostate. It is suggested that N-allylsecoboldine exhibits greater potency against nerve-mediated contraction than against phenylephrine-induced contraction in human hyperplastic prostate and that this antagonistic effect is due mainly to its high affinity for the alpha1A-adrenoceptor subtype.
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Affiliation(s)
- J H Guh
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei
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Stam WB, Van der Graaf PH, Saxena PR. Analysis of alpha 1L-adrenoceptor pharmacology in rat small mesenteric artery. Br J Pharmacol 1999; 127:661-70. [PMID: 10401556 PMCID: PMC1566064 DOI: 10.1038/sj.bjp.0702598] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
1. To illuminate the controversy on alpha 1A- or alpha 1L-adrenoceptor involvement in noradrenaline-mediated contractions of rat small mesenteric artery (SMA), we have studied the effects of subtype-selective alpha 1-adrenoceptor agonists and antagonists under different experimental conditions. 2. The agonist potency order in rat SMA was: A61603 >> SKF89748-A > cirazoline > noradrenaline > ST-587 > methoxamine. Prazosin antagonized all agonists with a low potency (pA2: 8.29-8.80) indicating the involvement of alpha 1L-rather than alpha 1A-adrenoceptors. 3. The putative alpha 1L-adrenoceptor antagonist JTH-601, but not the alpha 1B-adrenoceptor antagonist chloroethylclonidine (10 microM) antagonized noradrenaline-induced contractions of SMA. The potency of the selective alpha 1D-adrenoceptor antagonist BMY 7378 against noradrenaline (pA2 = 6.16 +/- 0.13) and of the selective alpha 1A-adrenoceptor antagonist RS-17053 against noradrenaline (pKB = 8.35 +/- 0.10) and against the selective alpha 1A-adrenoceptor agonist A-61603 (pKB = 8.40 +/- 0.09) were too low to account for alpha 1D- and alpha 1A-adrenoceptor involvement. 4. The potency of RS-17053 (pKB/pA2's = 7.72-8.46) was not affected by lowering temperature, changing experimental protocol or inducing myogenic tone via KCl or U46619. 5. Selective protection of a putative alpha 1A-adrenoceptor population against the irreversible action of phenoxybenzamine also failed to increase the potency of RS-17053 (pA2 = 8.25 +/- 0.06 against A61603). 6. Combined concentration-ratio analysis demonstrated that tamsulosin, which does not discriminate between alpha 1A- and alpha 1L-adrenoceptors, and RS-17053 competed for binding at the same site in the SMA. 7. In summary, data obtained in our experiments in rat SMA indicate that the alpha 1-adrenoceptor mediating noradrenaline-induced contraction displays a distinct alpha 1L-adrenoceptor pharmacology. This study does not provide evidence for the hypothesis that alpha 1L-adrenoceptors represent an affinity state of the alpha 1A-adrenoceptor in functional assays. Furthermore, there is no co-existing alpha 1A-adrenoceptor in the SMA.
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Affiliation(s)
- Wiro B Stam
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands
| | - Pieter H Van der Graaf
- Leiden/Amsterdam Center for Drug Research, Division of Pharmacology, Sylvius Laboratories, P.O. Box 9503, 2300 RA Leiden, The Netherlands
| | - Pramod R Saxena
- Department of Pharmacology, Faculty of Medicine and Health Sciences, Erasmus University Rotterdam, P.O. Box 1738, 3000 DR Rotterdam, The Netherlands
- Author for correspondence:
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Hiraoka Y, Ohmura T, Oshita M, Watanabe Y, Morikawa K, Nagata O, Kato H, Taniguchi T, Muramatsu I. Binding and functional characterization of alpha1-adrenoceptor subtypes in the rat prostate. Eur J Pharmacol 1999; 366:119-26. [PMID: 10064160 DOI: 10.1016/s0014-2999(98)00895-4] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
The alpha1-adrenoceptor subtypes of rat prostate were characterized in binding and functional experiments. In binding experiments, [3H]tamsulosin bound to a single class of binding sites with an affinity (pKD) of 10.79+/-0.04 and Bmax of 87+/-2 fmol mg(-1) protein. This binding was inhibited by prazosin, 2-(2,6-dimethoxy-phenoxyethyl)-aminomethyl-1,4-benzodioxane hydrochloride (WB4101), 5-methylurapidil, alpha-ethyl-3,4,5,-trimethoxy-alpha-(3-((2-(2-methoxyphenoxy)ethyl)-amin o)-propyl)benzeneacetonitrile fumarate (HV723) and oxymetazoline with high efficacy, resulting in a good correlation with the binding characteristics of cloned alpha1a but not alpha1b and alpha1d-adrenoceptor subtypes. In functional studies, noradrenaline and oxymetazoline produced concentration-dependent contractions. These contractions were antagonized by tamsulosin, prazosin, WB4101 and 5-methylurapidil with an efficacy lower than that exhibited by these agents for inhibition of [3H]tamsulosin binding. The relationship between receptor occupancy and contractile amplitude revealed the presence of receptor reserve for noradrenaline, but the contraction induced by oxymetazoline was not in parallel with receptor occupation and developed after predicted receptor saturation. From these results, it is suggested that alpha1A-adrenoceptors are the dominant subtype in the rat prostate which can be detected with [3H]tamsulosin, but that the functional subtype mediating adrenergic contractions has the characteristics of the alpha1L-adrenoceptor subtype, having a lower affinity for prazosin and some other drugs than the alpha1A-adrenoceptor subtype.
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Affiliation(s)
- Y Hiraoka
- Research and Development Division, Hokuriku Seiyaku, Katsuyama, Fukui, Japan
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Guh JH, Hwang TL, Ko FN, Chueh SC, Lai MK, Teng CM. Antiproliferative effect in human prostatic smooth muscle cells by nitric oxide donor. Mol Pharmacol 1998; 53:467-74. [PMID: 9495813 DOI: 10.1124/mol.53.3.467] [Citation(s) in RCA: 76] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
We obtained a primary culture of prostatic cells through explantation from patients with benign prostatic hyperplasia. Structural morphology, immunohistochemical staining, and growth characteristics of these cells demonstrate that they are consistent with the population of smooth muscle cells (SMCs). We examined the influence of a nitric oxide donor, sodium nitroprusside (SNP), on the regulation of human prostatic SMC proliferation. SNP exhibited a concentration-dependent (0.1-10 microM) inhibition of fetal calf serum-induced proliferation in human prostatic SMCs. In addition, growth-inhibitory responses to 8-bromo-cGMP (1-30 muM) were observed. However, the responses to SNP were significantly diminished by the presence of 1H-[1,2,4]oxadiazolo[4,3-a]quinoxalin-1-one (3 microM; a selective guanylate cyclase inhibitor). Furthermore, SNP induced an increased concentration-dependent accumulation of intracellular cGMP in human prostatic SMCs. After 48-hr period of deprivation of serum, cells were restimulated with serum to permit cell cycle progression. The addition of SNP (10 microM) at various times after the addition of serum to serum-deprived cells showed maximal inhibition of cell proliferation even when added 6 hr after the serum. This blocking effect of cell cycle progression was lost gradually as the delay from serum to SNP application increased from 6 to 18 hr. The membrane-associated protein kinase C (PKC) activity was studied in human prostatic SMCs; results showed that fetal calf serum (10%, v/v) significantly increased membrane-associated PKC activity. SNP (10 muM), which had little effect on basal kinase activity, completely abolished serum-induced augmentation of PKC activity. Therefore, we suggest that SNP mediates its antiproliferative effect by the inhibition of PKC activity on human prostatic SMCs; furthermore, its antiproliferative effect occurs at the early G1 phase of the cell cycle.
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Affiliation(s)
- J H Guh
- Pharmacological Institutes and Drug Research and Development Group, College of Medicine, National Taiwan University, Taipei, Taiwan, Republic of China
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Haynes JM, Hill SJ. Beta-adrenoceptor-mediated inhibition of alpha 1-adrenoceptor-mediated and field stimulation-induced contractile responses in the prostate of the guinea pig. Br J Pharmacol 1997; 122:1067-74. [PMID: 9401771 PMCID: PMC1565050 DOI: 10.1038/sj.bjp.0701494] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
1. The prostate of the guinea pig responds to electrical field-stimulation (2 s trains, 0.1 ms pulses at 3-60 Hz, supramaximal voltage) with contractile responses. At 18 Hz these responses were inhibited (82 +/- 2%) by the L-type Ca2+ channel blocker, nifedipine (10 microM) and (by 100%) by the neurotoxin, tetrodotoxin (500 nM). The alpha 1A-selective adrenoceptor antagonist, 5-methylurapidil, inhibited responses to field stimulation in the absence and presence of nifedipine (10 microM) with -log molar (p) IC50 (+/- s.e. mean) values of 7.95 +/- 0.14 and 7.01 +/- 0.07, respectively. 2. The non-selective beta-adrenoceptor agonist, isoprenaline, reduced (56 +/- 8%) field stimulation induced contractile responses (pEC50 6.91 +/- 0.11). The non-selective beta-adrenoceptor antagonist propranolol (50 nM) and the beta 1-adrenoceptor selective antagonist, atenolol (3 microM), but not the beta 2-adrenoceptor antagonist ICI 118,551 ((+/-)-1 -[2,3-(dihydro-7-methyl-1H-inden-4-yl)oxyl]-3-[1-methylethyl)amino ]-2-butanol HCl; 100 nM) antagonized this effect (apparent pKB values 8.44 +/- 0.22 and 6.92 +/- 0.21, respectively) indicating an effect mediated through beta 1-like adrenoceptors. In the presence of nifedipine (10 microM) isoprenaline (up to 10 microM) did not inhibit the remaining response to field-stimulation. 3. Phenylephrine elicited contractile responses (pEC50 4.47 +/- 0.30) from preparations of guinea pig prostate which were reduced (63 +/- 25%) by nifedipine (10 microM). This response was antagonized by 5-methylurapidil (100 nM, apparent pKB 8.24 +/- 0.33), but was not affected by preincubation chloroethylclonidine (50 microM, 30 min). Responses to phenylephrine (30 microM) were inhibited (by up to 52 +/- 5%) by isoprenaline (pIC50 6.40 +/- 0.35, the beta 2-adrenoceptor selective agonist, salbutamol was weakly effective). Propranolol (300 nM), ICI 118,551 (100 nM) and atenolol (3 microM) shifted isoprenaline concentration-response curves to the right (apparent pKB +/- s.e. values 7.68 +/- 1.10; 8.00 +/- 0.72 and 6.62 +/- 0.95, respectively). In the presence of nifedipine (10 microM) responses to phenylephrine (30 microM,) were inhibited (by up to 51 +/- 4%) by isoprenaline (pIC50 6.88 +/- 0.17): propranolol (300 nM) and ICI 118,551 (100 nM), but not atenolol (3 microM) antagonized this effect (apparent pKB values 8.85 +/- 1.53 and 8.35 +/- 1.18, respectively). Thus beta 1-like and beta 2-like adrenoceptors may be involved in the isoprenaline-stimulated inhibition of phenylephrine concentration-response curves. 4. Phenylephrine stimulated [3H]-inositol phosphate accumulation (pEC50 4.47 +/- 0.83), an effect insensitive to chloroethylclonidine pre-treatment (50 microM, 30 min) and to nifedipine (10 microM), but inhibited by 5-methylurapidil (apparent pKD 7.90 +/- 0.22). Isoprenaline (up to 1 microM) did not affect the phenylephrine-stimulated maximal increase in [3H]-inositol phosphates but did increase [3H]-cyclic adenosine monophosphate ([3H]-cAMP) accumulation (pEC50 6.77 +/- 0.66); propranolol (30 nM) and ICI 118,551 (110 nM), but not atenolol (up to 3 microM), antagonized this effect. These responses may therefore be mediated through beta 2-like adrenoceptors. 5. These results show that the alpha 1-adrenoceptor mediated and field stimulation-induced contractions of the guinea pig prostate are partly dependent upon intracellular and extracellular sources of Ca2+. We conclude that both beta 1- and beta 2-like adrenoceptors inhibit responses to phenylephrine in the prostate of the guinea pig. The beta 1-like adrenoceptor-mediated inhibition of these responses is evident upon the field stimulation-induced and nifedipine-sensitive component of the response to phenylephrine and may not involve the activation of adenylyl cyclase. The beta 2-like adrenoceptor may inhibit both nifedipine sensitive and insensitive components of the response to phenylephrine, possibly through the activation of adenylyl cyclase, but not through the i
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Affiliation(s)
- J M Haynes
- Department of Physiology and Pharmacology, Medical School, Queen's Medical Centre, Nottingham
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Affiliation(s)
- P Mátyus
- Semmelweis University of Medicine, Institute of Organic Chemistry, Budapest, Hungary
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Takeda M, Hatano A, Komeyama T, Koizumi T, Mizusawa T, Kanai T, Tomita Y, Maruyama K, Nagatomo T. Alpha-1 adrenoceptor subtypes (high, low) in human benign prostatic hypertrophy tissue according to the affinities for prazosin. Prostate 1997; 31:216-22. [PMID: 9180931 DOI: 10.1002/(sici)1097-0045(19970601)31:4<216::aid-pros2>3.0.co;2-i] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
BACKGROUND A novel classification of alpha-1 adrenoceptor subtypes (High, Low) was applied to human benign prostatic hypertrophy (BPH) tissue. METHODS Human BPH specimens were examined by a radioligand binding assay method using 3H-prazosin, and those data were compared with preoperative therapies. RESULTS (1) Scatchard analysis showed a high-affinity site (Kd:27.18 +/- 6.41 pM; Bmax:9.29 +/- 0.98 fM/mg protein; mean +/- SE) as alpha 1H, and a low-affinity site (Kd: 4088.0 +/- 744.34 pM, Bmax: 140.81 +/- 19.98 fM/mg protein) as alpha 1L subtype, for prazosin. (2) The Kd and Bmax were not different in the nontreated group (n = 5), alpha 1 blocker group (n = 5), and antiandrogen group (n = 5), in either alpha 1-high affinity or alpha 1-low affinity subtype. (3) Phenoxybenzamine had different pKi values for the above two adrenoceptor subtypes. Scatchard analysis showed that alpha 1-high affinity binding site disappeared in the presence of 1 microM of phenoxybenzamine, and the Kd and Bmax values in the presence of 1 microM of phenoxybenzamine were almost identical to the alpha 1-low affinity site of the two subtypes. CONCLUSIONS Human BPH tissue possesses both alpha 1H- and alpha 1L-adrenoceptor subtypes according to the affinities for prazosin, and only the alpha 1H subtype can be completely inhibited by some concentration of phenoxybenzamine. Treatment by alpha 1 blocker may not change the conditions of alpha 1-adrenoceptors in prostatic tissue.
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Affiliation(s)
- M Takeda
- Department of Urology, Niigata University, School of Medicine, Japan
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Abstract
BACKGROUND alpha 1-adrenoceptor antagonists (blockers) are now commonly used in the treatment of the symptoms of lower urinary tract obstruction. Originally phenoxybenzamine, a non-selective antagonist at both alpha 1- and alpha 2-adrenoceptors, was used by Marco Caine. In an attempt to minimize side effects, selective alpha 1-antagonists, e.g. prazosin, were subsequently developed. More recently, agents such as alfuzosin, doxazosin, terazosin, and tamsulosin have been introduced and claims of "uroselectivity" and "prostate" selectivity have emerged. METHODS This review attempts to put these claims into perspective and represents a comprehensive analysis of all pre-clinical and clinical data including several papers from the Japanese literature. An attempt is made to define what is meant by selectivity at various levels including the test tube, in the laboratory animal and, most importantly, in the clinical context of the whole patient. CONCLUSIONS The conclusions are interpreted within the context of the subdivision of the alpha 1-adrenoceptor into alpha 1A, alpha 1B, and alpha 1D subtypes.
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Affiliation(s)
- K E Andersson
- Department of Clinical Pharmacology, Lund University Hospital, Sweden
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Chess-Williams R, Chapple CR, Verfurth F, Noble AJ, Couldwell CJ, Michel MC. The effects of SB 216469, an antagonist which discriminates between the alpha 1A-adrenoceptor and the human prostatic alpha 1-adrenoceptor. Br J Pharmacol 1996; 119:1093-100. [PMID: 8937710 PMCID: PMC1915881 DOI: 10.1111/j.1476-5381.1996.tb16009.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
1. The affinity of the alpha 1-adrenoceptor antagonist SB 216469 (also known as REC 15/2739) has been determined at native and cloned alpha 1-adrenoceptor subtypes by radioligand binding and at functional alpha 1-adrenoceptor subtypes in isolated tissues. 2. In radioligand binding studies with [3H]-prazosin, SB 216469 had a high affinity at the alpha 1A-adrenoceptors of the rat cerebral cortex and kidney (9.5-9.8) but a lower affinity at the alpha 1B-adrenoceptors of the rat spleen and liver (7.7-8.2). 3. At cloned rat alpha 1-adrenoceptor subtypes transiently expressed in COS-1 cells and also at cloned human alpha 1-adrenoceptor subtypes stably transfected in Rat-1 cells, SB 216469 exhibited a high affinity at the alpha 1a-adrenoceptors (9.6-10.4) with a significantly lower affinity at the alpha 1b-adrenoceptor (8.0-8.4) and an intermediate affinity at the alpha 1d-adrenoceptor (8.7-9.2). 4. At functional alpha 1-adrenoceptors, SB 216469 had a similar pharmacological profile, with a high affinity at the alpha 1A-adrenoceptors of the rat vas deferens and anococcygeus muscle (pA2 = 9.5-10.0), a low affinity at the alpha 1B-adrenoceptors of the rat spleen (6.7) and guinea-pig aorta (8.0), and an intermediate affinity at the alpha 1D-adrenoceptors of the rat aorta (8.8). 5. Several recent studies have concluded that the alpha 1-adrenoceptor present in the human prostate has the pharmacological characteristics of the alpha 1A-adrenoceptor subtype. However, the affinity of SB 216469 at human prostatic alpha 1-adrenoceptors (pA2 = 8.1) determined in isolated tissue strips, was significantly lower than the values obtained at either the cloned alpha 1a-adrenoceptors (human, rat, bovine) or the native alpha 1A-adrenoceptors in radioligand binding and functional studies in the rat. 6. Our results with SB 216469, therefore, suggest that the alpha 1-adrenoceptor mediating contractile responses of the human prostate has properties which distinguish it from the cloned alpha 1a-adrenoceptor or native alpha 1A-adrenoceptor. Since it has previously been shown that the receptor is not the alpha 1B- or alpha 1D-adrenoceptor, the functional alpha 1-adrenoceptor of the human prostate may represent a novel receptor with properties which differ from any of the alpha 1-adrenoceptors currently defined by pharmacological means.
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Chueh SC, Guh JH, Chen J, Lai MK, Ko FN, Teng CM. Inhibition by tamsulosin of tension responses of human hyperplastic prostate to electrical field stimulation. Eur J Pharmacol 1996; 305:177-80. [PMID: 8813550 DOI: 10.1016/0014-2999(96)00197-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Tamsulosin (10(-10)-10(-9) M) or prazosin (10(-9)-10(-8) M) concentration dependently blocked the tension responses to electrical field stimulation (0.3 ms duration, 80 V and 20 Hz) in human hyperplastic prostate with lC50 values of (1.93 +/- 0.26) x 10(-10) M and (2.11 +/- 0.21) x 10(-9) M, respectively. The relative potency of tamsulosin with reference to prazosin was 10.96. The pA2 values for tamsulosin and prazosin against phenylephrine-induced contractions were 10.05 +/- 0.16 and 9.25 +/- 0.07, respectively. The relative potency of tamsulosin with reference to prazosin was 6.31. In the presence of prazosin to block alpha 1-adrenoceptor-mediated responses, nifedipine (10(-5) M), but not tamsulosin (10(-9) M), significantly blocked the tension responses in human hyperplastic prostate induced by increasing [Ca2+]o concentrations (10(-4) to 3 x 10(-3) M) in a Ca(2+)-free environment pre-depolarized with 60 mM K+. Additionally, the effects of prazosin and tamsulosin on electrical field stimulation-evoked [3H]noradrenaline release were studied on the S3/S2 ratios. It appeared that both drugs had little effect on this release reaction, with S3/S2 ratios of 0.96 +/- 0.02 and 0.90 +/- 0.02, respectively. These results indicate that tamsulosin is a potent antagonist against endogenous sympathetic stimulation in human hyperplastic prostate.
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Affiliation(s)
- S C Chueh
- Department of Urology, College of Medicine, National Taiwan University, Taipei
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Guh JH, Ko FN, Chueh SC, Lai MK, Teng CM. Ouabain-induced increases in resting tone of human hyperplastic prostate following repeated noradrenaline and electrical field stimulation. Br J Pharmacol 1996; 117:1716-20. [PMID: 8732281 PMCID: PMC1909572 DOI: 10.1111/j.1476-5381.1996.tb15344.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
1. The effect of ouabain on contractions to repeated noradrenaline stimulation and electrical field stimulation of human hyperplastic prostate was examined. Ouabain (1 microM) did not induce contractile response per se but progressively increased the resting tone (i.e., the tone between one noradrenaline stimulation, or electrical field stimulation, and the following) of human hyperplastic prostate. 2. The increased tone by ouabain following repeated noradrenaline stimulations or electrical field stimulation was fully relaxed by the removal of external calcium, and recovered following restoration of calcium. 3. The effect of noradrenaline on NA+ uptake was measured. Noradrenaline (10 microM) significantly increased the rate of Na+ accumulation in the presence of ouabain (1 microM); this stimulatory effect was almost completely blocked by prazosin (0.1 microM) and ethylisopropylamiloride (100 microM). In contrast, tetrodotoxin (1 microM) had no effect on noradrenaline-stimulated Na+ transport in human hyperplastic prostate. 4. Intracellular Na+ loading by noradrenaline (10 microM) in the presence of ouabain (1 microM) significantly increased the transmembrane Ca2+ uptake as compared with the absence of ouabain; however, nifedipine (1 microM) was ineffective on Ca2+ uptake under this condition. 5. Transmembrane CA2+ efflux was stimulated by noradrenaline (10 microM) in human hyperplastic prostate; this effect was significantly decreased in the presence of ouabain (1 microM). 6. It is suggested that the increased tone of human hyperplastic prostate following repeated excitation in the presence of ouabain is due to increased Ca2+ entry and reduced efflux of Ca2+ through the Na+/Ca+ exchange system as a consequence of Na+ pump inhibition by ouabain.
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Affiliation(s)
- J H Guh
- Pharmacological Institute, College of Medicine, National Taiwan University, Taipei, Taiwan
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Michel MC, Grübbel B, Taguchi K, Verfürth F, Otto T, Kröpfl D. Drugs for treatment of benign prostatic hyperplasia: affinity comparison at cloned alpha 1-adrenoceptor subtypes and in human prostate. JOURNAL OF AUTONOMIC PHARMACOLOGY 1996; 16:21-8. [PMID: 8736427 DOI: 10.1111/j.1474-8673.1996.tb00352.x] [Citation(s) in RCA: 81] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
1. We have previously shown that among alpha 1-adrenoceptor antagonists used or investigated for the treatment of benign prostatic hyperplasia, tamsulosin discriminates alpha 1-adrenoceptor subtypes in rat tissues whereas alfuzosin and naftopidil do not. We now expand these studies to additional drugs (doxazosin, terazosin) being used and/or investigated for this purpose, and have evaluated all of these drugs at cloned subtypes and in human prostate. 2. Competition binding studies were performed with [3H]-prazosin in membrane samples from rat spleen, kidney and cerebral cortex and human prostate and with cloned alpha 1-adrenoceptors expressed in COS cells. Doxazosin and terazosin did not discriminate alpha 1-adrenoceptor subtypes in rat kidney and cerebral cortex. In contrast, the subtypes present in the tissues were well discriminated by the alpha 1A-adrenoceptor-selective reference drug WB 4101. 3. Alfuzosin, doxazosin, naftopidil and terazosin did not discriminate cloned alpha 1-adrenoceptor subtypes transiently expressed in COS cells whereas tamsulosin and WB 4101 did. 4. In human prostate, alfuzosin, doxazosin, naftopidil and terazosin did not discriminate the alpha 1-adrenoceptor subtypes present in this tissue whereas tamsulosin and the alpha 1A-adrenoceptor-selective reference drugs WB 4101, phentolamine and 5-methylurapidil did. Based on data with the alpha 1A-adrenoceptor-selective drugs, human prostate contains alpha 1A- and alpha 1B-adrenoceptors in an approximate 70:30% ratio. 5. We conclude that tamsulosin, in common with WB 4101, but in contrast to alfuzosin, doxazosin, naftopidil, and terazosin is selective for alpha 1A-adrenoceptors which appear to dominate in the human prostate; the therapeutic relevance of this selectivity remains to be assessed in clinical studies.
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Affiliation(s)
- M C Michel
- Dept. of Medicine, University of Essen, Germany
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