Cardiovascular effects of chronic treatment with a β 2- adrenoceptor agonist relieving neuropathic pain in mice
Institut des Neurosciences Cellulaires et Intégratives, Centre National de la Recherche Scientifique, 21 rue René Descartes, 67084 Strasbourg cedex, France. Neuropharmacology
(Impact Factor: 5.11).
02/2011; 61(1-2):51-60. DOI: 10.1016/j.neuropharm.2011.02.015
Neuropathic pain is often a chronic condition, disabling and difficult to treat. Using a murine model of neuropathic pain induced by placing a polyethylene cuff around the main branch of the sciatic nerve, we have shown that chronic treatment with β-AR agonists is effective against neuropathic allodynia. β-mimetics are widely used against asthma and chronic obstructive pulmonary disease and may offer an interesting option for neuropathic pain management. The most prominent adverse effects of chronic treatment with β-mimetics are cardiovascular. In this study, we compared the action of low doses of the selective β(2)-AR agonist terbutaline and of a high dose of the mixed β(1)/β(2)-AR agonist isoproterenol on cardiovascular parameters in a neuropathic pain context. Isoproterenol was used as a positive control for some heart-related changes. Cardiac functions were studied by echocardiography, hemodynamic measurements, histological analysis of fibrosis and cardiac hypertrophy, and by quantitative real time PCR analysis of atrial natriuretic peptide (Nppa), periostin (Postn), connective tissue growth factor (Ctgf) and β-myosin heavy chain (Myh7). Our data show that a chronic treatment with the β(2)-AR agonist terbutaline at low antiallodynic dose does not affect cardiovascular parameters, whereas the mixed β(1)/β(2)-AR agonist isoproterenol induces cardiac hypertrophy. These data suggest that low doses of β(2)-AR agonists may provide a suitable treatment with rare side effects in neuropathic pain management. This study conducted in an animal model requires clinical confirmation in humans.
Available from: Luca Filippi
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ABSTRACT: In a mouse model of oxygen-induced retinopathy (OIR), a well-established model of retinopathy of prematurity (ROP), blocking beta-adrenoreceptors (β-ARs), and, in particular, β2-ARs, counteracts retinal responses to hypoxia. In the present work, we determined the effects of the β-AR agonist isoproterenol on retinal angiogenesis and β-AR signaling to better clarify the role of sympathetic transmission in ROP.
Isoproterenol was administered subcutaneously. Protein kinase A activity was determined by a colorimetric assay to assess drug effectiveness. Blood pressure and heart-to-body weight ratio were measured. Vascular endothelial growth factor (VEGF) and norepinephrine were measured with ELISA. Retinal neovascularization was assessed by CD31 immunohistochemistry. β-AR-coupled adenylyl cyclase (AC) activity was measured with a competition assay. β-ARs, G-protein-coupled receptor kinase (GRK)2, and β-arrestins were determined by Western blot. Association of β-arrestins with β2-ARs was assessed by immunoprecipitation.
Isoproterenol-induced modulation of protein kinase A activity suggests that the drug was effective at the receptor level. Isoproterenol did not affect cardiovascular parameters, but decreased retinal levels of VEGF and reduced pathogenic neovascularization, likely through an influence on sympathetic transmission. In fact, isoproterenol downregulated β2-AR expression, recovered the hypoxia-induced increase in β-AR-coupled AC activity, and increased GRK2 and β-arrestins, which promote β-AR desensitization through the uncoupling of G-protein-coupled receptors from G proteins. Immunoprecipitation studies demonstrated that β-AR desensitization involved β2-ARs.
Our findings suggest that hypoxia-induced retinal neovascularization depends at least in part on increased sympathetic transmission, as reduction of sympathetic drive by agonist-induced β2-AR desensitization inhibits some of the hallmarks of OIR.
Investigative ophthalmology & visual science 03/2012; 53(4):2181-92. DOI:10.1167/iovs.11-9408 · 3.40 Impact Factor
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ABSTRACT: Neuropathic pain is a pain arising as a direct consequence of a lesion or disease affecting the somatosensory system. It is usually chronic and challenging to treat. Some antidepressants are first-line pharmacological treatments for neuropathic pain. The noradrenaline that is recruited by the action of the antidepressants on reuptake transporters has been proposed to act through β2-adrenoceptors (β2-ARs) to lead to the observed therapeutic effect. However, the complex downstream mechanism mediating this action remained to be identified. In this study, we demonstrate in a mouse model of neuropathic pain that antidepressant's effect on neuropathic allodynia involves the peripheral nervous system and the inhibition of cytokine Tumor Necrosis Factor α (TNFα) production. The antiallodynic action of nortriptyline is indeed lost after peripheral sympathectomy, but not after lesion of central descending noradrenergic pathways. More particularly, we report that antidepressant-recruited noradrenaline acts, within dorsal root ganglia, on β2-ARs expressed by non-neuronal satellite cells. This stimulation of β2-ARs decreases the neuropathy-induced production of membrane-bound TNFα, resulting in relief of neuropathic allodynia. This indirect anti-TNFα action was observed with the tricyclic antidepressant nortriptyline, the selective serotonin and noradrenaline reuptake inhibitor venlafaxine and the β2-AR agonist terbutaline. Our data revealed an original therapeutic mechanism that may open novel research avenues for the management of painful peripheral neuropathies.
Neurobiology of Disease 08/2013; 60. DOI:10.1016/j.nbd.2013.08.012 · 5.08 Impact Factor
Available from: PubMed Central
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ABSTRACT: This study was undertaken to determine the association between cardiac function and therapy with beta2-adrenoceptor agonists (β2-agonists), β-blockers, or β-blocker-β-agonist combination therapy in elderly male patients with chronic obstructive pulmonary disease (COPD).
This was a retrospective cohort study of 220 elderly male COPD patients (mean age 84.1 ± 6.9 years). The patients were divided into four groups on the basis of the use of β-blockers and β2-agonists. N-terminal fragment pro-B-type natriuretic peptide (NT pro-BNP), left ventricular ejection fraction (LVEF), and other relevant parameters were measured and recorded. At follow-up, the primary end point was all-cause mortality.
Multiple linear regression analysis revealed no significant associations between NT pro-BNP and the use of β2-agonists (β = 35.502, P = 0.905), β-blockers (β = 3.533, P = 0.989), or combination therapy (β = 298.635, P = 0.325). LVEF was not significantly associated with the use of β2-agonists (β = -0.360, P = 0.475), β-blockers (β = -0.411, P = 0.284), or combination therapy (β = -0.397, P = 0.435). Over the follow-up period, 52 patients died, but there was no significant difference in mortality among the four groups (P = 0.357). Kaplan-Meier analysis showed no significant difference among the study groups (log-rank test, P = 0.362). After further multivariate adjustment, use of β2-agonists (hazard ratio [HR] 0.711, 95% confidence interval [CI] 0.287-1.759; P = 0.460), β-blockers (HR 0.962, 95% CI 0.405-2.285; P = 0.930), or combination therapy (HR 0.638, 95% CI 0.241-1.689; P < 0.366) were likewise not correlated with mortality.
There was no association between the use of β2-agonists, β-blockers, or β-blocker-β2-agonist combination therapy with cardiac function and all-cause mortality in elderly male COPD patients, which indicated that they may be used safely in this population.
Clinical Interventions in Aging 09/2013; 8:1157-65. DOI:10.2147/CIA.S49644 · 2.08 Impact Factor
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