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Rivera-Mancilla E, Avilés-Rosas VH, Manrique-Maldonado G, Altamirano-Espinoza AH, Villanueva-Castillo B, MaassenVanDenBrink A, Villalón CM. The role of α 1- and α 2-adrenoceptor subtypes in the vasopressor responses induced by dihydroergotamine in ritanserin-pretreated pithed rats. J Headache Pain 2017; 18:104. [PMID: 29022279 PMCID: PMC5636772 DOI: 10.1186/s10194-017-0812-4] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2017] [Accepted: 09/26/2017] [Indexed: 08/30/2023] Open
Abstract
Background Dihydroergotamine (DHE) is an acute antimigraine agent that displays affinity for dopamine D2-like receptors, serotonin 5-HT1/2 receptors and α1/α2-adrenoceptors. Since activation of vascular α1/α2-adrenoceptors results in systemic vasopressor responses, the purpose of this study was to investigate the specific role of α1- and α2-adrenoceptors mediating DHE-induced vasopressor responses using several antagonists for these receptors. Methods For this purpose, 135 male Wistar rats were pithed and divided into 35 control and 100 pretreated i.v. with ritanserin (100 μg/kg; to exclude the 5-HT2 receptor-mediated systemic vasoconstriction). Then, the vasopressor responses to i.v. DHE (1–3100 μg/kg, given cumulatively) were determined after i.v. administration of some α1/α2-adrenoceptor antagonists. Results In control animals (without ritanserin pretreatment), the vasopressor responses to DHE were: (i) unaffected after prazosin (α1; 30 μg/kg); (ii) slightly, but significantly, blocked after rauwolscine (α2; 300 μg/kg); and (iii) markedly blocked after prazosin (30 μg/kg) plus rauwolscine (300 μg/kg). In contrast, after pretreatment with ritanserin, the vasopressor responses to DHE were: (i) attenuated after prazosin (α1; 10 and 30 μg/kg) or rauwolscine (α2; 100 and 300 μg/kg); (ii) markedly blocked after prazosin (30 μg/kg) plus rauwolscine (300 μg/kg); (iii) attenuated after 5-methylurapidil (α1A; 30–100 μg/kg), L-765,314 (α1B; 100 μg/kg), BMY 7378 (α1D; 30–100 μg/kg), BRL44408 (α2A; 100–300 μg/kg), imiloxan (α2B; 1000–3000 μg/kg) or JP-1302 (α2C; 1000 μg/kg); and (iv) unaffected after the corresponding vehicles (1 ml/kg). Conclusion These results suggest that the DHE-induced vasopressor responses in ritanserin-pretreated pithed rats are mediated by α1- (probably α1A, α1B and α1D) and α2- (probably α2A, α2B and α2C) adrenoceptors. These findings could shed light on the pharmacological profile of the vascular side effects (i.e. systemic vasoconstriction) produced by DHE and may lead to the development of more selective antimigraine drugs devoid vascular side effects.
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Affiliation(s)
- Eduardo Rivera-Mancilla
- Department of Pharmacobiology, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P, 14330, Mexico City, Mexico
| | - Victor H Avilés-Rosas
- Department of Pharmacobiology, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P, 14330, Mexico City, Mexico
| | - Guadalupe Manrique-Maldonado
- Department of Pharmacobiology, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P, 14330, Mexico City, Mexico
| | - Alain H Altamirano-Espinoza
- Department of Pharmacobiology, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P, 14330, Mexico City, Mexico
| | - Belinda Villanueva-Castillo
- Department of Pharmacobiology, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P, 14330, Mexico City, Mexico
| | - Antoinette MaassenVanDenBrink
- Division of Vascular Medicine and Pharmacology, Erasmus University Medical Center, P.O. Box 2040, 3000, CA, Rotterdam, The Netherlands
| | - Carlos M Villalón
- Department of Pharmacobiology, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P, 14330, Mexico City, Mexico.
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Villamil-Hernández MT, Alcántara-Vázquez O, Sánchez-López A, Centurión D. Pharmacological identification of α1- and α2-adrenoceptor subtypes involved in the vasopressor responses induced by ergotamine in pithed rats. Eur J Pharmacol 2013; 715:262-9. [PMID: 23707349 DOI: 10.1016/j.ejphar.2013.05.011] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Revised: 04/26/2013] [Accepted: 05/11/2013] [Indexed: 11/24/2022]
Abstract
Ergotamine has been used in clinical practice for the acute treatment of migraine for over 90 years. So far, it is known that ergotamine interacts with diverse receptors (including α1/2-adrenoceptors, 5-HT1, 5-HT2 and D2-like receptors) and that produces increases in mean blood pressure which are significantly blocked by yohimbine, a classical α2-adrenoceptor antagonist with a moderate affinity for α1-adrenoceptors. Since α1/2-adrenoceptors mediate vasopressor and vasoconstrictor responses in the cardiovascular system, this study was designed to identify the α-adrenoceptor subtypes (α1A, α1B, α1D, α2A, α2B and α2C) involved in ergotamine-induced vasopressor responses in pithed rats. In male Wistar pithed rats baseline heart rate and blood pressure were recorded. Then, the vasopressor responses to intravenous (i.v.) bolus injections of ergotamine were determined after administration of vehicle or several α1⧸2-adrenoceptor antagonists. I.v. administration of the antagonists prazosin (α1, 0.1-30 µg/kg), rauwolscine (α2, 0.3-300 µg/kg), prazosin (0.1 µg/kg) plus rauwolscine (0.3 µg/kg), 5-methylurapidil (α1A, 100 and 300 µg/kg), L-765,314 (α1B, 100 and 300 µg/kg), BMY 7378 (α1D, 100 and 300 µg/kg), BRL44408 (α2A, 300 and 1000 µg/kg) and JP-1302 (α2C, 300 µg/kg), significantly blocked the vasopressor responses to ergotamine, whereas imiloxan (α2B, 1000 and 3000 µg/kg), JP-1302 (100 µg/kg) or the corresponding vehicles (saline 0.9%, propylene glycol 20% or dimethyl sulfoxide 10%; 1ml/kg) failed to modify the responses to ergotamine. The above results suggest that the vasopressor responses to ergotamine in pithed rats are mainly mediated by α1A-, α1B-, α1D-, α2A- and α2C-adrenoceptors and may explain its adverse/therapeutic effects.
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Affiliation(s)
- Ma Trinidad Villamil-Hernández
- Departamento de Farmacobiología, Cinvestav-Coapa, Czda. de los Tenorios 235, Col. Granjas-Coapa, Deleg. Tlalpan, C.P. 14330 México D.F., México
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Pharmacological identification of the α2-adrenoceptor subtypes mediating the vasopressor responses to B-HT 933 in pithed rats. Eur J Pharmacol 2012; 691:118-24. [DOI: 10.1016/j.ejphar.2012.06.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2012] [Revised: 06/04/2012] [Accepted: 06/09/2012] [Indexed: 11/21/2022]
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Vasopressor nerve responses in the pithed rat, previously identified as α2-adrenoceptor mediated, may be α1D-adrenoceptor mediated. Eur J Pharmacol 2011; 658:182-6. [PMID: 21376031 DOI: 10.1016/j.ejphar.2011.02.029] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2010] [Revised: 01/20/2011] [Accepted: 02/05/2011] [Indexed: 11/21/2022]
Abstract
Responses to pressor nerve stimulation in the pithed rat have been variously described as mediated, at least in part, by α(2)-adrenoceptors and by α(1A) and α(1D)-adrenoceptors. We have examined the subtypes of α-adrenoceptor involved in rises in diastolic blood pressure in the pithed rat preparation produced by vasopressor nerve stimulation with 10 pulses at 1 Hz or 20 pulses at 5 Hz. Vasopressor nerve responses to 1 Hz stimulation were markedly inhibited by the α(1A)-adrenoceptor antagonist RS 100329 (0.1mg/kg) and by the α(1D-)adrenoceptor antagonist BMY 7378 (0.1mg/kg). The α(2)-adrenoceptor antagonist yohimbine (0.1mg/kg) significantly increased pressor nerve responses to 1 Hz stimulation, but yohimbine (1mg/kg) significantly reduced pressor nerve responses. However, following BMY 7378 (0.1mg/kg), yohimbine (1mg/kg) did not produce any further inhibition of pressor nerve responses to 1 Hz stimulation. The α(2A)-adrenoceptor antagonist BRL 44408 (1mg/kg) did not reduce pressor responses to 1 Hz stimulation. BMY 7378 produced much less inhibition of pressor nerve responses to 5 Hz stimulation, whereas RS 100329 produced similar inhibition of 1 Hz and 5 Hz responses. Yohimbine (0.1 and 1mg/kg) did not significantly affect pressor nerve responses to 5 Hz stimulation. In conclusion, pressor nerve responses in the pithed rat involve both α(1A) and α(1D)-adrenoceptor, but there is no clear evidence for the involvement of α(2)-adrenoceptors.
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El-Sabbagh O, Shabaan MA, Kadry HH, Al-Din ES. New octahydroquinazoline derivatives: Synthesis and hypotensive activity. Eur J Med Chem 2010; 45:5390-6. [DOI: 10.1016/j.ejmech.2010.08.064] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2010] [Revised: 08/25/2010] [Accepted: 08/26/2010] [Indexed: 10/19/2022]
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Elayan HH, Sun P, Milic M, Liu F, Bao X, Ziegler MG. Cardiovascular responses to electrical stimulation of sympathetic nerves in the pithed mouse. Auton Neurosci 2008; 140:49-52. [PMID: 18407806 DOI: 10.1016/j.autneu.2008.03.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2007] [Revised: 02/21/2008] [Accepted: 03/05/2008] [Indexed: 10/22/2022]
Abstract
The pithed rat model has been used extensively to study peripheral cardiovascular responses to electrical stimulation of the sympathetic nervous system, as pithing eliminates central and reflex effects. However, since the transgenic mouse has become a standard and economical model organism, an electrically stimulated pithed mouse would facilitate a variety of studies. We have developed surgical techniques, drug doses and stimulation parameters for an electrically stimulated pithed mouse to study peripheral sympathetic nerve effects on blood pressure. Similar to the pithed rat, the pithed mouse showed voltage and frequency-dependent blood pressure responses to a pulsed train of electrical stimuli. In addition, alpha-adrenergic stimulation with phenylephrine gave a marked systolic pressor response, while the beta2 agonist salbutamol lowered diastolic blood pressure. Furthermore, pithed transgenic mice unable to synthesize catecholamines in adrenergic cells displayed smaller pressor responses than pithed control mice. In summary, the electrically stimulated pithed mouse can be used to study peripheral effects of the sympathetic system on cardiovascular dynamics unencumbered by central responses.
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López-Guerrero JJ, Ibarra M, Villalobos-Molina R. Postjunctional alpha1-adrenoceptors in the vasculature of the pithed mouse are of the alpha1A-subtype. ACTA ACUST UNITED AC 2006; 25:101-3. [PMID: 15955029 DOI: 10.1111/j.1474-8673.2005.00338.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
1. The pressor action of noradrenaline and its blockade by selective alpha(1)-adrenoceptor antagonists in the pithed mouse were evaluated. 2. Chloroethylclonidine (alpha(1B/D)-adrenoceptor alkylating agent) or BMY 7378 (alpha(1D)-adrenoceptor antagonist), both at 1 mg kg(-1), did not block the increase in blood pressure induced by noradrenaline. 3. 5-Methylurapidil (alpha(1A)-adrenoceptor antagonist), at 0.1 mg kg(-1), displaced the dose-response curve approximately six-fold to the right. 4. The results support the idea that the pithed mouse vasculature express alpha(1A)-adrenoceptors and suggest that it is a good model to study the roles of alpha(1)-adrenoceptors in gene knockout or overexpression.
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Affiliation(s)
- J J López-Guerrero
- Departamento de Farmacobiología, Centro de Investigación y de Estudios Avanzados, Sede Sur, México D.F
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Shafaroudi MM, McBride M, Deighan C, Wokoma A, Macmillan J, Daly CJ, McGrath JC. Two "knockout" mouse models demonstrate that aortic vasodilatation is mediated via alpha2a-adrenoceptors located on the endothelium. J Pharmacol Exp Ther 2005; 314:804-10. [PMID: 15878998 DOI: 10.1124/jpet.105.085944] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
UK-14,304 [5-bromo-N-(4,5-dihydro-1H-imidazol-2-yl)-6-quinoxalinamine]-mediated vasodilator responses were studied on wire myograph-mounted mouse aorta to determine the cells involved, mechanisms of action, and subtypes of alpha(2)-adrenoceptors. In the presence of induced tone, UK-14,304 produced concentration-related vasodilatation that was abolished by rauwolscine, N(omega)-nitro-L-arginine methyl ester (L-NAME), or endothelium removal, indicating that endothelial alpha(2)-adrenoceptors can release nitric oxide. In the alpha(2A)-adrenoceptor knockout mouse and the D79N mouse, a functional knockout of the alpha(2A)-adrenoceptor, these relaxant effects of UK-14,304 were lost, indicating the involvement of the alpha(2A)-adrenoceptor. UK-14,304 could also contract aorta: a small contraction occurred at high concentrations, was enhanced by L-NAME, and was absent in the alpha(1D)-adrenoceptor knockout mouse, indicating activation of the alpha(1D)-adrenoceptor. There was no evidence for a contractile alpha(2)-adrenoceptor-mediated response. A fluorescent ligand, quinazoline piperazine bodipy, antagonized the relaxant action of UK-14,304. This compound could be visualized on aortic endothelial cells, and its binding could be prevented by rauwolscine, providing direct evidence for the presence of alpha(2)-adrenoceptors on the endothelium. Norepinephrine reduced tone in the alpha(1D)-adrenoceptor knockout and controls, an effect blocked by rauwolscine and L-NAME but not by prazosin. This suggests that norepinephrine activates endothelial alpha(2)-adrenoceptors. In conclusion, the endothelium of mouse aorta has an alpha(2A)-adrenoceptor that responds to norepinephrine; promotes the release of nitric oxide, causing smooth muscle relaxation; and that can be directly visualized. Knockout or genetic malfunction of this receptor should increase arterial stiffness, exacerbated by raised catecholamines, and contribute to heart failure.
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MESH Headings
- Animals
- Aorta, Thoracic/drug effects
- Brimonidine Tartrate
- Dose-Response Relationship, Drug
- Endothelial Cells/drug effects
- Endothelial Cells/metabolism
- Endothelium, Vascular/drug effects
- Endothelium, Vascular/metabolism
- Enzyme Inhibitors/pharmacology
- Fluorescent Dyes
- Image Processing, Computer-Assisted
- In Vitro Techniques
- Male
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Confocal
- Myography
- NG-Nitroarginine Methyl Ester/pharmacology
- Nitric Oxide/metabolism
- Norepinephrine/pharmacology
- Quinoxalines/pharmacology
- Receptors, Adrenergic, alpha-2/drug effects
- Receptors, Adrenergic, alpha-2/genetics
- Vasoconstrictor Agents/pharmacology
- Vasodilation/drug effects
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Affiliation(s)
- Majid Malekzadeh Shafaroudi
- Autonomic Physiology Unit, Institute of Biomedical and Life Sciences, West Medical Bldg., University of Glasgow, Glasgow G12 8QQ, Scotland, UK
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Pérez-Rivera AA, Fink GD, Galligan JJ. Increased Reactivity of Murine Mesenteric Veins to Adrenergic Agonists: Functional Evidence Supporting Increased α1-Adrenoceptor Reserve in Veins Compared with Arteries. J Pharmacol Exp Ther 2003; 308:350-7. [PMID: 14593081 DOI: 10.1124/jpet.103.056184] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
These studies examined adrenergic reactivity of mesenteric arteries and veins from deoxycorticosterone acetate-salt (DOCA-salt) hypertensive and sham control mice. We measured constrictions in unpressurized arteries and veins by monitoring vessel diameter using computer-assisted video micros-copy in vitro. Veins were more sensitive than arteries to the constricting effects of norepinephrine (NE) and phenylephrine (PE), but the alpha2-agonists clonidine and UK 14,304 [5-bromo-6-(2-imidazolin-2-yl-amino)-quinoxaline] did not constrict arteries or veins. Reactivity was not altered in arteries or veins from DOCA-salt mice. We next investigated the mechanism of increased venous reactivity to NE and PE by studying desensitization to maximum concentrations of NE and PE. Sham arteries desensitized to NE and PE more than DOCA-salt arteries, whereas DOCA-salt and sham veins maintained 80% of the initial NE and PE constriction. To determine whether the increased reactivity and resistance to desensitization in veins was due to a greater alpha-adrenoceptor reserve, vessels were incubated with the alkylating agent phenoxybenzamine (PBZ; 0.3, 3, 10, and 30 nM). The NE-elicited initial constriction was reduced by PBZ (3, 10, and 30 nM) in sham but only by PBZ (30 nM) in DOCA-salt veins. All doses of PBZ blocked NE responses in sham and DOCA-salt arteries. These data suggest that mesenteric veins express more alpha1-adrenoceptors than arteries, accounting for greater reactivity and resistance to desensitization compared with arteries.
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Affiliation(s)
- Alex A Pérez-Rivera
- Department of Pharmacology and Toxicology, Michigan State University, East Lansing, Michigan 48824, USA.
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Boesen EI, Lewis TV, Kett MM, Anderson WP. Effects of preweaning doxazosin treatment on adult pressure in the spontaneously hypertensive rat. Clin Exp Pharmacol Physiol 2003; 30:555-7. [PMID: 12890177 DOI: 10.1046/j.1440-1681.2003.03868.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
1. The neonatal/preweaning period appears to represent a critical period of involvement of the sympathetic nervous system in the development of hypertension in spontaneously hypertensive rats (SHR). 2. We tested whether alpha1-adrenoceptor-mediated effects during the preweaning period are involved in the development of hypertension in the adult SHR. 3. Male SHR were treated with the alpha1-adrenoceptor antagonist doxazosin (10 mg/kg per day, s.c.) from postnatal day 1 to 21 inclusive. Direct conscious blood pressure and heart rate were measured via the caudal artery at 12 weeks of age. 4. Preweaning treatment with doxazosin had no significant effect on mean arterial blood pressure or heart rate in male SHR at 12 weeks of age. 5. These findings do not support the involvement of alpha1-adrenoceptor-mediated effects during the preweaning period in the development of hypertension in adult SHR.
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Affiliation(s)
- Erika I Boesen
- Department of Physiology Monash University, Melbourne, Victoria, Australia.
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Civantos Calzada B, Aleixandre de Artiñano A. Distribución y función de los receptores alfaadrenérgicos del músculo liso vascular. HIPERTENSION Y RIESGO VASCULAR 2003. [DOI: 10.1016/s1889-1837(03)71398-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Abstract
Different studies have led to our present knowledge of the membrane receptors responsible for mediating the responses to the endogenous catecholamines. These receptors were initially differentiated into alpha - and beta-adrenoceptors. Alpha-adrenoceptors mediate most excitatory functions, and were in turn differentiated in the 1970s into alpha(1)- and alpha(2)-adrenoceptors. The alpha(1)-adrenoceptor type usually mediates responses in the effector organ. The alpha(2)-adrenoceptor type is located presynaptically and regulates the release of the neurotransmitter but it is also present in postsynaptical locations. Both alpha-adrenoceptors are important for the control of vascular tone, but we now know that neither alpha(1)- nor alpha(2)-adrenoceptors constitute homogeneous groups. Each alpha-adrenoceptor type can be subdivided into different subtypes and in this review we have turned our attention to these. The alpha(1)- and the alpha(2)-adrenoceptor subtypes were previously defined pharmacologically by functional and binding studies, and later they were also isolated and identified using cloning methods. In fact, the study of alpha-adrenoceptors was revolutionized by the techniques of molecular biology which permitted us to establish the present classification. The present classification of alpha(1)-adrenoceptors stands as follows: alpha(1A)-adrenoceptor subtype (cloned alpha(1c) and redesignated alpha(1a/c)), alpha(1B)-adrenoceptor subtype (cloned alpha(1b)) and alpha(1D)-adrenoceptor subtype (cloned alpha(1d) and redesignated alpha(1a/d)). It has not been easy to establish the distribution of these alpha(1)-adrenoceptor subtypes in the various organs and tissues, or to define the functional response mediated by each one in the different species studied. Nevertheless it seems that the alpha(1A)-adrenoceptor subtype is more implicated in the maintenance of vascular basal tone and of arterial blood pressure in conscious animals, and the alpha(1B)-adrenoceptor subtype participates more in responses to exogenous agonists. It has also been observed that the expression of the alpha(1B)-adrenoceptor subtype can be modified in pathological situations and particular attention has been paid to the regulation of expression of this receptor. The present classification of alpha(2)-adrenoceptors stands as follows: alpha(2A/D)-adrenoceptor subtype (today it is accepted that the alpha(2A)-adrenoceptor subtype and the alpha(2D)-adrenoceptor subtype are the same receptor but they were identified in different species: the alpha(2A) in human and the alpha(2D) in rat); alpha(2B)-adrenoceptor subtype (cloned alpha(2b)) and alpha(2C)-adrenoceptor subtype (cloned alpha(2c)). Today we know that the alpha(2A/D)- and alpha(2B)-adrenoceptor subtypes in particular control arterial contraction, and that the alpha(2C)-adrenoceptor subtype is responsible above all for venous vasoconstriction. We also know that the alpha(2 A/D)-adrenoceptor subtype fundamentally mediates the central effects of the alpha(2)-adrenoceptor agonists. Despite the validity of the above-mentioned classification of the alpha(1)- and alpha(2)-adrenoceptors, it seems clear that the contractions of a large number of tissues including smooth muscle are mediated by more than one alpha-adrenoceptor subtype. Moreover, few ligands recognise only one alpha-adrenoceptor subtype and the lack of specifity in the different drugs for each one limits their administration in vivo and their therapeutic use.
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MESH Headings
- Adrenergic alpha-Agonists/pharmacology
- Adrenergic alpha-Antagonists/pharmacology
- Animals
- Humans
- Receptors, Adrenergic, alpha/classification
- Receptors, Adrenergic, alpha/physiology
- Receptors, Adrenergic, alpha-1/classification
- Receptors, Adrenergic, alpha-1/physiology
- Receptors, Adrenergic, alpha-2/classification
- Receptors, Adrenergic, alpha-2/physiology
- Terminology as Topic
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Affiliation(s)
- B Civantos Calzada
- Departamento de Farmacología, Facultad de Medicina, Universidad Complutense de Madrid, Spain
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Hieble JP. Adrenoceptor subclassification: an approach to improved cardiovascular therapeutics. PHARMACEUTICA ACTA HELVETIAE 2000; 74:163-71. [PMID: 10812954 DOI: 10.1016/s0031-6865(99)00030-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The subdivision of alpha adrenoceptors into the alpha 1 and alpha 2 classes was the impetus for the design of the selective alpha 1-adrenoceptor antagonists, which remain useful antihypertensives. alpha 2-Adrenoceptor agonists also have application as antihypertensive drugs, based on their ability to reduce sympathetic outflow. Likewise, subdivision of the beta adrenoceptors has lead to the development of selective beta 1-adrenoceptor antagonists as antihypertensive and selective beta 2 agonists as bronchodilators. In the past decade, both the alpha 1 and alpha 2 adrenoceptors have been further subdivided, each into three subclasses. In addition, there is strong functional evidence to suggest the presence of additional adrenoceptor subtypes, such as the "alpha 1L" adrenoceptor and "beta 4" adrenoceptor. alpha 1A (or alpha 1L)-Adrenoceptor antagonists have been evaluated for benign prostatic hyperplasia (BPH), and selective alpha 1A agonists for stress incontinence. Gene knockout experiments in mice suggest an important role for the alpha 1B adrenoceptor in the control of vascular tone. Hence, selective alpha 1B antagonists may offer a new approach toward hypertension. Although targeting of specific adrenoceptors can be used to optimize the therapeutic profile of a drug, there are also cases where blockade of multiple adrenoceptors is desirable, as with the alpha/beta-adrenoceptor antagonist carvedilol in congestive heart failure. It is possible that combination of affinities for selected adrenoceptor subtypes within a single molecule may be desirable for certain applications.
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Affiliation(s)
- J P Hieble
- Division of Pharmacological Sciences, SmithKline Beecham Pharmaceuticals, King of Prussia, PA 19406, USA
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