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Fitzgerald BC. Cardiovascular Diseases in Pet Birds: Therapeutic Options and Challenges. Vet Clin North Am Exot Anim Pract 2022; 25:469-501. [PMID: 35422263 DOI: 10.1016/j.cvex.2022.01.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
Cardiovascular disease, including congestive heart failure, pericardial disease, and atherosclerosis, is becoming increasingly better recognized in companion birds. A wide range of medications is available to treat these conditions, including diuretics, vasodilators, positive and negative inotropes, antiarrhythmic agents, and pentoxifylline. This review systematically discusses each of these drug classes and their potential applications in avian species. Although treatment approaches remain largely empirical and extrapolated from small animal and human medicine, the management strategies presented here have the potential to both maintain quality of life and extend survival time for the avian cardiac patient.
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Affiliation(s)
- Brenna Colleen Fitzgerald
- Avian Exclusive Veterinary Consultation (AEVC), Englewood, Colorado; Homestead Animal Hospital, Centennial, Colorado.
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Yikilmaz Y, Kuzukiran O, Erdogan E, Sen F, Kirmizibayrak O, Filazi A. The determination of β-agonist residues in bovine tissues using liquid chromatography-tandem mass spectrometry. Biomed Chromatogr 2020; 34:e4926. [PMID: 32558952 DOI: 10.1002/bmc.4926] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2020] [Revised: 06/08/2020] [Accepted: 06/14/2020] [Indexed: 12/12/2022]
Abstract
We aimed to develop a rapid, simple and reproducible method based on LC-tandem mass spectrometry (LC-MS/MS) to analyze β-agonist residues (clenbuterol, zilpaterol, ractopamine and isoxsuprine) in bovine tissues. The method was validated in accordance with the European Council Decision 2002/657/EC. The samples were homogenized, and then 10 mL of an acetate buffer was added to a 5-g sample. The sample was then centrifuged at 12,000 rpm and filtered. Sodium hydroxide (2 m) was added to adjust pH of the sample that was centrifuged again. The extract was filtered through a solid-phase extraction column. The residue was re-dissolved in 250 μL acetonitrile and then subjected to LC-MS/MS. The separation was done on a C18 column. The mobile phase consisted of 0.1% formic acid in deionized water and 0.1% formic acid in methanol. The mean recoveries of β-agonists were in the range of 84.3%-119.1% with relative standard deviations (%RSDs) of 0.683%-4.05%. Decision limits and detection capabilities of the analytes ranged from 0.0960 to 4.9349 μg/kg and from 0.0983 to 5.0715, respectively. This method was used to detect four β-agonists in 100 bovine muscle, 100 liver and 100 kidney tissues from a slaughterhouse. No residue was found above the maximum residue limit level.
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Affiliation(s)
- Yeliz Yikilmaz
- Etlik Veterinary Research Control Institute, Ahmet Sefik Kolaylı Street, Ankara, 06100, Turkey
| | - Ozgur Kuzukiran
- Veterinary Department, Eldivan Vocational School of Health Services, Cankiri Karatekin University, Cankiri, 18700, Turkey
| | - Ekrem Erdogan
- Etlik Veterinary Research Control Institute, Ahmet Sefik Kolaylı Street, Ankara, 06100, Turkey
| | - Filiz Sen
- Etlik Veterinary Research Control Institute, Ahmet Sefik Kolaylı Street, Ankara, 06100, Turkey
| | - Ozlem Kirmizibayrak
- Etlik Veterinary Research Control Institute, Ahmet Sefik Kolaylı Street, Ankara, 06100, Turkey
| | - Ayhan Filazi
- Department of Pharmacology and Toxicology, Faculty of Veterinary Medicine, Ankara University, Sehit Omer Halisdemir Street., Ankara, 06110, Turkey
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Medina-Ruiz D, Erreguin-Luna B, Luna-Vázquez FJ, Romo-Mancillas A, Rojas-Molina A, Ibarra-Alvarado C. Vasodilation Elicited by Isoxsuprine, Identified by High-Throughput Virtual Screening of Compound Libraries, Involves Activation of the NO/cGMP and H₂S/K ATP Pathways and Blockade of α₁-Adrenoceptors and Calcium Channels. Molecules 2019; 24:molecules24050987. [PMID: 30862086 PMCID: PMC6429095 DOI: 10.3390/molecules24050987] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 03/05/2019] [Accepted: 03/08/2019] [Indexed: 12/21/2022] Open
Abstract
Recently, our research group demonstrated that uvaol and ursolic acid increase NO and H2S production in aortic tissue. Molecular docking studies showed that both compounds bind with high affinity to endothelial NO synthase (eNOS) and cystathionine gamma-lyase (CSE). The aim of this study was to identify hits with high binding affinity for the triterpene binding-allosteric sites of eNOS and CSE and to evaluate their vasodilator effect. Additionally, the mechanism of action of the most potent compound was explored. A high-throughput virtual screening (HTVS) of 107,373 compounds, obtained from four ZINC database libraries, was performed employing the crystallographic structures of eNOS and CSE. Among the nine top-scoring ligands, isoxsuprine showed the most potent vasodilator effect. Pharmacological evaluation, employing the rat aorta model, indicated that the vasodilation produced by this compound involved activation of the NO/cGMP and H2S/KATP signaling pathways and blockade of α1-adrenoceptors and L-type voltage-dependent Ca2+ channels. Incubation of aorta homogenates in the presence of isoxsuprine caused 2-fold greater levels of H2S, which supported our preliminary in silico data. This study provides evidence to propose that the vasodilator effect of isoxsuprine involves various mechanisms, which highlights its potential to treat a wide variety of cardiovascular diseases.
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Affiliation(s)
- Daniella Medina-Ruiz
- Posgrado en Ciencias Químico Biológicas, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, Querétaro C.P. 76010, Mexico.
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - Berenice Erreguin-Luna
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - Francisco J Luna-Vázquez
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - Antonio Romo-Mancillas
- Laboratorio de Diseño Asistido por Computadora y Síntesis de Fármacos, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - Alejandra Rojas-Molina
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
| | - César Ibarra-Alvarado
- Laboratorio de Investigación Química y Farmacológica de Productos Naturales, Facultad de Química, Universidad Autónoma de Querétaro, Centro Universitario, Querétaro 76010, Mexico.
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Shahrokhian S, Hafezi-Kahnamouei M. Glassy carbon electrode modified with a nanocomposite of multi-walled carbon nanotube decorated with Ag nanoparticles for electrochemical investigation of Isoxsuprine. J Electroanal Chem (Lausanne) 2018. [DOI: 10.1016/j.jelechem.2018.08.010] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
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Fitzgerald BC, Dias S, Martorell J. Cardiovascular Drugs in Avian, Small Mammal, and Reptile Medicine. Vet Clin North Am Exot Anim Pract 2018; 21:399-442. [PMID: 29655477 DOI: 10.1016/j.cvex.2018.01.015] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Cardiovascular disease, including congestive heart failure, pericardial disease, and atherosclerosis, is becoming increasingly better recognized in companion birds, small mammals, and reptiles. A wide range of medications is available to treat these conditions, including diuretics, vasodilators, positive and negative inotropes, antiarrhythmic agents, and pentoxifylline. This review systematically discusses each of these drug classes and their potential applications in exotic species. Although treatment approaches remain largely empirical and extrapolated from small animal and human medicine, the management strategies presented here have the potential to both maintain quality of life and extend survival time for the exotic cardiac patient.
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Affiliation(s)
| | - Sara Dias
- Exotic Animals Department, Hospital Clínic Veterinari, Universitat Autònoma de Barcelona, Carrer de l'Hospital, Campus UAB, Bellaterra (Cerdanyola del Vallés), Barcelona 08193, Spain
| | - Jaume Martorell
- Facultat de Veterinaria, Universitat Autònoma de Barcelona, Hospital Clinic Veterinari, Bellaterra, Barcelona 08193, Spain
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Zizzadoro C, Caruso M, Punzi S, Crescenzo G, Zongoli F, Belloli C. A comparative study between responses of isolated bovine and equine digital arteries to vasoactive mediators. J Vet Pharmacol Ther 2017; 41:51-59. [DOI: 10.1111/jvp.12436] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 06/07/2017] [Indexed: 01/17/2023]
Affiliation(s)
- C. Zizzadoro
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | - M. Caruso
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | - S. Punzi
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | - G. Crescenzo
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
| | | | - C. Belloli
- Division of Veterinary Pharmacology and Toxicology; Department of Veterinary Medicine; University of Bari; Valenzano Bari Italy
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Hill JW, Thompson JF, Carter MB, Edwards BS, Sklar LA, Rosenberg GA. Identification of isoxsuprine hydrochloride as a neuroprotectant in ischemic stroke through cell-based high-throughput screening. PLoS One 2014; 9:e96761. [PMID: 24804769 PMCID: PMC4013073 DOI: 10.1371/journal.pone.0096761] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 04/07/2014] [Indexed: 11/25/2022] Open
Abstract
Stroke is a leading cause of death and disability and treatment options are limited. A promising approach to accelerate the development of new therapeutics is the use of high-throughput screening of chemical libraries. Using a cell-based high-throughput oxygen-glucose deprivation (OGD) model, we evaluated 1,200 small molecules for repurposed application in stroke therapy. Isoxsuprine hydrochloride was identified as a potent neuroprotective compound in primary neurons exposed to OGD. Isoxsuprine, a β2-adrenergic agonist and NR2B subtype-selective N-methyl-D-aspartate (NMDA) receptor antagonist, demonstrated no loss of efficacy when administered up to an hour after reoxygenation in an in vitro stroke model. In an animal model of transient focal ischemia, isoxsuprine significantly reduced infarct volume compared to vehicle (137±18 mm3 versus 279±25 mm3, p<0.001). Isoxsuprine, a peripheral vasodilator, was FDA approved for the treatment of cerebrovascular insufficiency and peripheral vascular disease. Our demonstration of the significant and novel neuroprotective action of isoxsuprine hydrochloride in an in vivo stroke model and its history of human use suggest that isoxsuprine may be an ideal candidate for further investigation as a potential stroke therapeutic.
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Affiliation(s)
- Jeff W. Hill
- University of New Mexico Health Sciences Center, Department of Neurology, Albuquerque, New Mexico, United States of America
- * E-mail:
| | - Jeffrey F. Thompson
- University of New Mexico Health Sciences Center, Department of Neurology, Albuquerque, New Mexico, United States of America
| | - Mark B. Carter
- Center for Molecular Discovery, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Bruce S. Edwards
- Center for Molecular Discovery, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Larry A. Sklar
- Center for Molecular Discovery, University of New Mexico Health Sciences Center, Albuquerque, New Mexico, United States of America
| | - Gary A. Rosenberg
- University of New Mexico Health Sciences Center, Department of Neurology, Albuquerque, New Mexico, United States of America
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In vitro inhibition of breast cancer spheroid-induced lymphendothelial defects resembling intravasation into the lymphatic vasculature by acetohexamide, isoxsuprine, nifedipin and proadifen. Br J Cancer 2013; 108:570-8. [PMID: 23299527 PMCID: PMC3593542 DOI: 10.1038/bjc.2012.580] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Background: As metastasis is the prime cause of death from malignancies, there is vibrant interest to discover options for the management of the different mechanistic steps of tumour spreading. Some approved pharmaceuticals exhibit activities against diseases they have not been developed for. In order to discover such activities that might attenuate lymph node metastasis, we investigated 225 drugs, which are approved by the US Food and Drug Administration. Methods: A three-dimensional cell co-culture assay was utilised measuring tumour cell-induced disintegrations of the lymphendothelial wall through which tumour emboli can intravasate as a limiting step in lymph node metastasis of ductal breast cancer. The disintegrated areas in the lymphendothelial cell (LEC) monolayers were induced by 12(S)-HETE, which is secreted by MCF-7 tumour cell spheroids, and are called ‘circular chemorepellent induced defects' (CCIDs). The putative mechanisms by which active drugs prevented the formation of entry gates were investigated by western blotting, NF-κB activity assay and by the determination of 12(S)-HETE synthesis. Results: Acetohexamide, nifedipin, isoxsuprine and proadifen dose dependently inhibited the formation of CCIDs in LEC monolayers and inhibited markers of epithelial-to-mesenchymal-transition and migration. The migration of LECs is a prerequisite of CCID formation, and these drugs either repressed paxillin levels or the activities of myosin light chain 2, or myosin-binding subunit of myosin phosphatase. Isoxsuprine inhibited all three migration markers, and isoxsuprine and acetohexamide suppressed the synthesis of 12(S)-HETE, whereas proadifen and nifedipin inhibited NF-κB activation. Both the signalling pathways independently cause CCID formation. Conclusion: The targeting of different mechanisms was most likely the reason for synergistic effects of different drug combinations on the inhibition of CCID formation. Furthermore, the treatment with drug combinations allowed also a several-fold reduction in drug concentrations. These results encourage further screening of approved drugs and their in vivo testing.
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Groot MJ, Lasaroms JJP, Van Hende J, Nielen M. Veterinary treatment of cows with isoxsuprine for a caesarian section may temporarily lead to residues in hair of both cow and calf. Drug Test Anal 2011; 4:515-8. [DOI: 10.1002/dta.272] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2010] [Revised: 12/14/2010] [Accepted: 01/15/2011] [Indexed: 11/09/2022]
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Badino P, Odore R, Re G. Are so many adrenergic receptor subtypes really present in domestic animal tissues? A pharmacological perspective. Vet J 2005; 170:163-74. [PMID: 16129337 DOI: 10.1016/j.tvjl.2004.05.015] [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] [Accepted: 05/21/2004] [Indexed: 11/17/2022]
Abstract
Adrenergic receptors (ARs) are the cellular membrane binding sites through which natural catecholamines and sympathomimetic drugs exert their physiological and pharmacological effects. In recent decades, studies to clarify the distribution and function of ARs have been performed mostly on cultured cells, laboratory animals and human target tissues, but little is known about these aspects in domestic animals. This review focuses on AR structure, classification and signalling pathways and on AR subtype distribution in target tissues of some domestic animals, namely dogs, horses and bovines. In these species, different alpha- and beta-AR subtypes have been characterized and the functions controlled by the adrenergic systems have been studied. In the dog, the role played by the adrenergic system in the pathogenesis of cardiovascular disorders and in the modulation of canine aggression has roused particular interest. In dogs affected by dilated cardiomyopathy a significant down-regulation of beta-ARs has been observed both in the heart and circulating lymphocytes. This finding confirms the involvement of the adrenergic system in the pathogenesis and progression of the disorder and suggests new therapeutic strategies. In the horse, AR distribution has been studied in the cardiac, respiratory and gastrointestinal systems as well as in digital veins and arteries. The cardiac beta-ARs in healthy horses seem to be predominantly represented by the beta(1) subtype. In this species, heart failure may increase the expression of the beta(2) subtype, rather than causing AR down-regulation. Different beta- and alpha-AR subtypes have been characterized in the smooth muscle of equine ileum. The sympathetic relaxation of equine ileum smooth muscle seems to depend mainly on beta(3)-AR subtype activation, with minor involvement of the beta(2) subtype. In the respiratory tract, regional differences have been evidenced in the functionality of beta-AR subtype. The beta(2) subtype predominates in all segments but the beta(2) subtype-mediated adenyl cyclase response is tissue-dependent, with higher activity in tracheal membranes than bronchial or pulmonary ones. Both alpha- and beta-AR subtypes are present in the genital tract of cows. Bovine ovarian and myometrial cell membranes express higher concentrations of beta(2)-ARs than the beta(1) subtype, whereas as far as alpha-ARs are concerned, a single class of alpha(1)-ARs and two distinct classes of alpha(2)-AR binding sites have been discriminated. Interestingly, it has been observed that the activation of the sympathetic system could play an important role in the pathogenesis of bovine ovarian cysts as suggested by the modifications in beta-AR levels in the hypophysis and ovary of cows affected by ovarian cysts. In this species, the phenomenon of down-regulation has been well studied in different organs of veal calves treated with clenbuterol as a "partitioning agent". Since differences exist in AR distribution among species, data obtained in laboratory animals or in human beings cannot be extrapolated to domestic animals and further investigation on AR subtypes in domestic animal tissues is necessary.
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Affiliation(s)
- P Badino
- Department of Animal Pathology, Division of Pharmacology and Toxicology, Faculty of Veterinary Medicine, University of Torino, via L. da Vinci 44, I-10095 Grugliasco, Torino, Italy
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Lizarraga I, Castillo F, Valderrama ME. An analgesic evaluation of isoxsuprine in horses. JOURNAL OF VETERINARY MEDICINE. A, PHYSIOLOGY, PATHOLOGY, CLINICAL MEDICINE 2004; 51:370-4. [PMID: 15533122 DOI: 10.1111/j.1439-0442.2004.00659.x] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/01/2023]
Abstract
Isoxsuprine is used clinically to treat navicular disease and laminitis in horses. Although it is thought to increase digital and laminar blood flow, isoxsuprine's mechanism of action remains controversial, and analgesia has been suggested recently as such possible mechanism. This research investigated the analgesic potential of isoxsuprine in healthy horses submitted to a mechanical nociceptive test. Isoxsuprine (1.2 mg/kg), xylazine (1.1 mg/kg), distilled water : ethanol 95% (2 : 1, v/v, 20 ml) and saline (0.9%, 20 ml) were injected intravenously, and nociceptive thresholds were measured over 90 min. Only xylazine significantly increased nociceptive thresholds, confirming that alpha(2)-adrenoceptor agonists produce analgesia in horses. Our results do not support an analgesic mechanism of action for isoxsuprine in horses, suggesting that other mechanisms might account for the clinical efficacy of this drug or that mechanical nociceptive testing may not be sufficiently sensitive to demonstrate an analgesic effect for this drug.
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Affiliation(s)
- I Lizarraga
- Department of Physiology and Pharmacology, School of Veterinary Medicine, National Autonomous University of Mexico, Av. Universidad 3000, Mexico City 04510, Mexico
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Beretta C, Cavalli M. A sheer pharmacologic approach to compare the contractile effects of PGF2α, dl-cloprostenol and d-cloprostenol on isolated uterine, tracheal, ileal and arterial smooth muscle preparations. Theriogenology 2004; 62:837-46. [PMID: 15251235 DOI: 10.1016/j.theriogenology.2003.12.012] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2003] [Revised: 10/31/2003] [Accepted: 12/04/2003] [Indexed: 11/18/2022]
Abstract
The contractile effects of PGF2alpha and its cloprostenol analogs (D-enantiomer and racemate) were examined on isolated smooth muscle preparations (uterine, tracheal, ileal and arterial) from rat, guinea-pig and horse. DL- and D-cloprostenol were potent contractors of myometrium, but had negligible secondary effects on other types of smooth muscle, except artery whose response to the D-enantiomer may give rise to some concern.
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Affiliation(s)
- C Beretta
- Department of Clinical Veterinary Sciences, University of Milan, Via Celoria 10, Milan 20133, Italy
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Belloli C, Badino P, Arioli F, Odore R, Re G. Adrenergic regulation of vascular smooth muscle tone in calf digital artery. J Vet Pharmacol Ther 2004; 27:247-54. [PMID: 15305854 DOI: 10.1111/j.1365-2885.2004.00588.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Radioligand binding studies and functional assays on isolated smooth muscle preparations were performed in order to obtain a biochemical and functional characterization of the beta-adrenoceptor (beta-AR) subtypes involved in regulation of the smooth muscle relaxation of the calf's common digital artery. The results indicate that the common digital artery possesses two beta-AR populations (40% beta(1) and 60% beta(2)) and the beta(2)-subtype appears to predominate as far as function is concerned. Only the beta(2)-AR agonists clenbuterol and fenoterol caused dose-related relaxant effects, antagonized by propranolol, when tested in preparations precontracted both with PGF(2alpha) (1.4 x 10(-5) m) and noradrenaline (1.2 x 10(-6) m). In noradrenaline precontracted preparations the beta(1)-AR selective agonists dobutamine and xamoterol caused vasodilation which was not antagonized by (+/-)propranolol. While the functional relaxant effects of dobutamine may be attributed to its potent competitive alpha-AR blocking activity, further investigations are required to explain the effect of xamoterol. The vasodilator effect of (+/-)isoproterenol was irregular. The recorded contractile effects, mainly at dosages greater than 10(-6) m, suggest the loss of drug selectivity for beta-AR and alpha-AR activation. Indirect evidence indicates that the alpha-adrenoceptor (alpha-AR) population in this tissue which produces a strong contraction is functionally dominant over the beta-AR, suggesting limited therapeutic benefit for beta-AR drugs to control blood flow disorders in the calf's distal limb.
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Affiliation(s)
- C Belloli
- Department of Animal Health and Welfare, Division of Veterinary Pharmacology and Toxicology, University of Bari, Valenzano, Italy
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