Expression Of Β3-adrenoceptors Research Articles

Salmonella-induced inhibition of β3-adrenoceptor expression in tumors and reduces tumor metastasis.

The β3-adrenoceptor is a protein responsible for regulating the body's response to the neurotransmitter adrenaline and the hormone norepinephrine. It is critical in various physiological processes, including metabolism, thermogenesis, and cardiovascular function. Recently, researchers have discovered that the β3-adrenoceptor is also implicated in tumor progression and metastasis. Infections caused by Salmonella can lead to gastroenteritis; however, intriguingly, Salmonella is associated with tumor inhibition. In this study, Salmonella treatment resulted in the downregulation of β3-adrenoceptor expression and a decrease in the phosphorylation of the Protein Kinase-B (AKT)/Mammalian Target of Rapamycin (mTOR) pathway, as observed through immunoblotting in a dose-dependent manner. Notably, Salmonella treatment significantly reduced tumor cell migration, as demonstrated by wound healing and Transwell assays. Moreover, tumor-bearing mice that received Salmonella-pre-treated tumor cells exhibited improved survival rates compared to those injected with tumor cells without prior Salmonella treatment. The observed anti-metastatic effect in this study suggests that Salmonella treatment could hold promise as a potential therapeutic approach to combat tumor metastasis. Further research is warranted to explore its full therapeutic potential.

β3 adrenoceptor agonist mirabegron protects against right ventricular remodeling and drives Drp1 inhibition.

The right ventricular (RV) function determines the prognosis of patients with pulmonary hypertension (PH). Metabolic disorders have been observed in the RV myocardium in PH. Activation of the β3 adrenoceptor improves cardiac function and restores cardiac metabolic efficiency in rodents with heart failure; however, its role in the RV remains uncertain. Experimental PH was induced by monocrotaline (MCT) in rats. Mirabegron, a selective β3 adrenoceptor agonist, was given to MCT rats daily from the day after MCT injection at the dose of 10 mg/kg. In vivo echocardiography and RV catheterization were performed to assess RV hemodynamics, structure, and function. RV fibrosis and hypertrophy were assessed by Sirius Red (SR) and wheat germ agglutinin (WGA) staining respectively. Western blotting was performed to examine the markers of RV fibrosis and hypertrophy, as well as the levels of the key molecules and their phosphorylated forms. The molecular changes were confirmed in the cardiac hypertrophy model of angiotensin II (Ang II) treated H9c2 cardiomyocytes using western blotting. The overloaded RV had increased β3 adrenoceptor expression, which was further increased by mirabegron. Mirabegron reduced RV pressure and reduced RV structural and functional deterioration in MCT rats. Mirabegron decreased cardiac fibrosis and hypertrophy in the overloaded RV. Mirabegron suppressed dynaminrelated protein 1 (Drp1) and promoted AMP-activated protein kinase (AMPK) signaling in the overloaded RV and Ang II treated cardiomyocytes. The β3 adrenoceptor agonist mirabegron reduced RV hypertrophy and fibrosis in PH rats. The treatment effect involved Drp1 inhibition and AMPK activation.

Inhibitory effects of vibegron, a β3-adrenoceptor agonist, on the myogenic contractile and mechanosensitive afferent activities in an obstructed rat bladder

To determine the role of β3-adrenoceptor agonists on bladder sensory facilitation related to bladder myogenic contractile activities in bladder hyperactivity, we investigated the effects of vibegron, a β3-adrenoceptor agonist, on the bladder and sensory function by evaluating cystometry and mechanosensitive single-unit afferent activities (SAAs), respectively, in a male rat model of bladder outlet obstruction (BOO).BOO was created by partial ligation of the urethra. Ten days after the surgical procedure, cystometric and SAA measurements were taken under two distinct conditions: a conscious-restrained condition, in which the bladder was constantly filled with saline, and a urethane-anesthetized condition involving an isovolumetric process with saline. For each measurement, vibegron (3 mg/kg) or its vehicle was administered intravenously after the data were reproducibly stable. In addition, the expression of β3-adrenoceptor and substance P (SP), a sensory neuropeptide, in the bladder was further evaluated following immunohistochemical procedures.Number of non-voiding contractions (NVCs) in cystometry was decreased after vibegron-administration, which was a significant change from vehicle group. Number of microcontractions and SAAs of Aδ- and C-fibers were significantly decreased by vibegron-administration. Furthermore, β3-adrenocepor and SP were co-expressed in the suburothelium layer of the bladder.These findings indicated that vibegron showed inhibitory effects on NVCs and microcontractions of the bladder, and SAAs of the Aδ- and C-fibers in BOO rats. The study suggested that vibegron can partly inhibit the mechanosensitive afferent transduction via Aδ- and C-fibers by suppressing bladder myogenic contractile activities in the rat bladder hyperactivity associated with BOO.

Restoring Perivascular Adipose Tissue Function in Obesity Using Exercise

PurposePerivascular adipose tissue (PVAT) exerts an anti-contractile effect which is vital in regulating vascular tone. This effect is mediated via sympathetic nervous stimulation of PVAT by a mechanism which involves noradrenaline uptake through organic cation transporter 3 (OCT3) and β3-adrenoceptor-mediated adiponectin release. In obesity, autonomic dysfunction occurs, which may result in a loss of PVAT function and subsequent vascular disease. Accordingly, we have investigated abnormalities in obese PVAT, and the potential for exercise in restoring function.MethodsVascular contractility to electrical field stimulation (EFS) was assessed ex vivo in the presence of pharmacological tools in ±PVAT vessels from obese and exercised obese mice. Immunohistochemistry was used to detect changes in expression of β3-adrenoceptors, OCT3 and tumour necrosis factor-α (TNFα) in PVAT.ResultsHigh fat feeding induced hypertension, hyperglycaemia, and hyperinsulinaemia, which was reversed using exercise, independent of weight loss. Obesity induced a loss of the PVAT anti-contractile effect, which could not be restored via β3-adrenoceptor activation. Moreover, adiponectin no longer exerts vasodilation. Additionally, exercise reversed PVAT dysfunction in obesity by reducing inflammation of PVAT and increasing β3-adrenoceptor and OCT3 expression, which were downregulated in obesity. Furthermore, the vasodilator effects of adiponectin were restored.ConclusionLoss of neutrally mediated PVAT anti-contractile function in obesity will contribute to the development of hypertension and type II diabetes. Exercise training will restore function and treat the vascular complications of obesity.

Zinc-α2-glycoprotein promotes skeletal muscle lipid metabolism in cold-stressed mice.

Skeletal muscle is the most abundant tissue in the adult body and plays an essential role in maintaining heat production for the entire body. Recently, muscle-derived non-shivering thermogenesis under cold conditions has received much attention. Zinc-α2-glycoprotein (ZAG) is an adipokine that was shown to influence energy metabolism in the adipose tissue. We used ZAG knock-out (ZAG KO) and wild-type (WT) mice to investigate the effect of ZAG on the lipid metabolism of skeletal muscle upon exposure to a low temperature (6°C) for one week. The results show that cold stress significantly increases the level of lipolysis, energy metabolism, and fat browning-related proteins in the gastrocnemius muscle of WT mice. In contrast, ZAG KO mice did not show any corresponding changes. Increased expression of β3-adrenoceptor (β3-AR) and protein kinase A (PKA) might be involved in the ZAG pathway in mice exposed cold stress. Furthermore, expression of lipolysis-related proteins (ATGL and p-HSL) and energy metabolism-related protein (PGC1α, UCP2, UCP3 and COX1) was significantly enhanced in ZAG KO mice after injection of ZAG-recombinant plasmids. These results indicate that ZAG promotes lipid-related metabolism in the skeletal muscle when the animals are exposed to low temperatures. This finding provides a promising target for the development of new therapeutic approaches to improve skeletal muscle energy metabolism.

Perivascular adipose tissue phenotype and sepsis vascular dysfunction: Differential contribution of NO, ROS and beta 3-adrenergic receptor

AimsVascular dysfunction plays a key role in sepsis but the role of perivascular adipose tissue (PVAT) in this condition is relatively unknown. Main methodsSepsis was induced by cecal ligation and puncture (CLP). The responses of the aorta and superior mesenteric artery to norepinephrine in the presence or absence of PVAT were evaluated. Fluorescent probes measured the production of nitric oxide (NO) and reactive oxygen species (ROS). NO synthases (NOS) and β3-adrenoceptor expression were detected by immunofluorescence and S-nitrosylation by the biotin switch assay. Key findingsAorta and superior mesenteric arteries from septic animals with intact PVAT showed a worsened response to the vasoconstrictor compared to vessels without PVAT. PVAT from the aorta (APVAT) produced NO and ROS whereas PVAT from the superior mesenteric artery (MPVAT) produced only ROS. Septic APVAT exhibited a higher density of NOS-1 and NOS-3. S-nitrosylation was found in APVAT. Donor (PVAT obtained from normal or septic rats):Host (normal vessel without PVAT) experiments showed that L-NAME, ODQ and β3-adrenergic receptor antagonist blocked the septic APVAT anti-contractile effect. None of these compounds affected MPVAT; tempol, but not apocynin, blocked its anti-contractile effect. SignificancePVAT contributes to the anti-contractile effect in the aorta and mesenteric artery of septic rats through different pathways. β3-Adrenergic receptor and NO appear to be key mediators of this effect in APVAT, but not in MPVAT where ROS seem to be a relevant mediator. Therefore, PVAT is a relevant player of sepsis vascular dysfunction.

PD24-02 ADDITIVE EFFECTS OF INTRAVENOUS AND INTRAVESICAL APPLICATION OF VIBEGRON, A β 3 -ADRENOCEPTOR AGONIST, ON BLADDER FUNCTION IN RATS WITH BLADDER OVERACTIVITY

You have accessJournal of UrologyBladder & Urethra: Anatomy, Physiology & Pharmacology II (PD24)1 Apr 2020PD24-02 ADDITIVE EFFECTS OF INTRAVENOUS AND INTRAVESICAL APPLICATION OF VIBEGRON, A β3-ADRENOCEPTOR AGONIST, ON BLADDER FUNCTION IN RATS WITH BLADDER OVERACTIVITY Akira Furuta*, Yasuyuki Suzuki, Taro Igarashi, Yusuke Koike, Shin Egawa, and Naoki Yoshimura Akira Furuta*Akira Furuta* More articles by this author , Yasuyuki SuzukiYasuyuki Suzuki More articles by this author , Taro IgarashiTaro Igarashi More articles by this author , Yusuke KoikeYusuke Koike More articles by this author , Shin EgawaShin Egawa More articles by this author , and Naoki YoshimuraNaoki Yoshimura More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000000881.02AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Approximately 20% of oral intake of vibegron, a new β3-adrenoceptor agonist, is excreted into urine in the unchanged form. Therefore, we examined the effects of intravesical application of vibegron on bladder function in rats with oxotremorine methiodide (oxo-M: a nonselective muscarinic acetylcholine receptor agonist) -induced bladder overactivity. METHODS: Cystometry was performed in conscious female rats with intravesical instillation of oxo-M (200μM). In oxo-M-treated rats, vehicle or vibegron (1, 10mg/kg) was cumulatively administered intravenously at 30-minute intervals. In another group of rats, vehicle or vibegron (10, 100μM, 1mM) was cumulatively instilled intravesically at 60-minute intervals followed by intravenously application of vibegron (10mg/kg). Time-dependent changes in bladder function via cumulative intravenous or intravesical application of vehicle were also exmained. In addition, expression of β3-adrenoceptors (ARs) in the rat bladder was evaluated using immunohistochemical staining. RESULTS: Intravesical instillation of oxo-M induced bladder overactivity as evidenced by decreases in bladder capacity with increases in baseline, threshold and maximal voiding pressure. In oxo-M-treated rats, intravenous application of vibegron (10mg/kg) significantly increased bladder capacity (1.2 times) and decreased baseline, threshold and maximal voiding pressure compared with vehicle. Next, intravesical application of vibegron (1mM) significantly increased threshold pressure and bladder capacity (1.2 times) compared with vehicle. Combined treatments of intravesical (1mM) and intravenous (10mg/kg) application of vibegron induced a significantly larger rate of increases in bladder capacity (1.4 times) compared with vehicle although there were no significant time-dependent changes in bladder function. In addition, β3-ARs were expressed throughout the rat bladder, mainly in the urothelium. CONCLUSIONS: These results suggest that vibegron excreted into urine as the unchanged form induces the additive inhibitory effects on urinary frequency possibly by activating urothelial β3-ARs, which inhibits the afferent limb of micturition reflex rather than the efferent function evident as the increases in threshold pressure and bladder capacity without affecting bladder contractile function. Source of Funding: None © 2020 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 203Issue Supplement 4April 2020Page: e532-e533 Advertisement Copyright & Permissions© 2020 by American Urological Association Education and Research, Inc.MetricsAuthor Information Akira Furuta* More articles by this author Yasuyuki Suzuki More articles by this author Taro Igarashi More articles by this author Yusuke Koike More articles by this author Shin Egawa More articles by this author Naoki Yoshimura More articles by this author Expand All Advertisement PDF downloadLoading ...

Transient Overexpression of Vascular Endothelial Growth Factor A in Adipose Tissue Promotes Energy Expenditure via Activation of the Sympathetic Nervous System.

Adipose-derived vascular endothelial growth factor A (VEGF-A) stimulates functional blood vessel formation in obese fat pads, which in turn facilitates healthy expansion of the adipose tissue. However, the detailed mechanism(s) governing the process remains largely unknown. Here, we investigated the role of sympathetic nervous system activation in the process. To this end, we induced overexpression of VEGF-A in an adipose tissue-specific doxycycline (Dox)-inducible transgenic mouse model for a short period of time during high-fat diet (HFD) feeding. We found that local overexpression of VEGF-A in adipose tissue stimulated lipolysis and browning rapidly after Dox induction. Immunofluorescence staining against tyrosine hydroxylase (TH) indicated higher levels of sympathetic innervation in adipose tissue of transgenic mice. In response to an increased norepinephrine (NE) level, expression of β3-adrenoceptor was significantly upregulated, and the downstream protein kinase A (PKA) pathway was activated, as indicated by enhanced phosphorylation of whole PKA substrates, in particular, the hormone-sensitive lipase (HSL) in adipocytes. As a result, the adipose tissue exhibited increased lipolysis, browning, and energy expenditure. Importantly, all of these effects were abolished upon treatment with the β3-adrenoceptor antagonist SR59230A. Collectively, these results demonstrate that transient overexpressed VEGF-A activates the sympathetic nervous system, which hence promotes lipolysis and browning in adipose tissue.

Rosiglitazone and a β3-Adrenoceptor Agonist Are Both Required for Functional Browning of White Adipocytes in Culture.

The recruitment of brite (or beige) adipocytes has been advocated as a means to combat obesity, due to their ability to phenotypically resemble brown adipocytes (BA). Lineage studies indicate that brite adipocytes are formed by differentiation of precursor cells or by direct conversion of existing white adipocytes, depending on the adipose depot examined. We have systematically compared the gene expression profile and a functional output (oxygen consumption) in mouse adipocytes cultured from two contrasting depots, namely interscapular brown adipose tissue, and inguinal white adipose tissue (iWAT), following treatment with a known browning agent, the peroxisome proliferator-activated receptor (PPARγ) activator rosiglitazone. Prototypical BA readily express uncoupling protein (UCP)1, and upstream regulators including the β3-adrenoceptor and transcription factors involved in energy homeostasis. Adipocytes from inguinal WAT display maximal UCP1 expression and mitochondrial uncoupling only when treated with a combination of the PPARγ activator rosiglitazone and a β3-adrenoceptor agonist. In conclusion, brite adipocytes are fully activated only when a browning agent (rosiglitazone) and a thermogenic agent (β3-adrenoceptor agonist) are added in combination. The presence of rosiglitazone throughout the 7-day culture period partially masks the effects of β3-adrenoceptor signaling in inguinal white adipocyte cultures, whereas including rosiglitazone only for the first 3 days promotes robust β3-adrenoceptor expression and provides an improved window for detection of β3-adrenoceptor responses.

Urothelial Barrier Deficits, Suburothelial Inflammation and Altered Sensory Protein Expression in Detrusor Underactivity

The pathophysiology of detrusor underactivity remains unclear and impaired bladder afferent function is considered one of the important etiologies. We investigated urothelial barrier deficits, suburothelial inflammation and sensory proteins expressed in the bladder mucosa of patients with detrusor underactivity. Bladder mucosa biopsies were performed in 34 patients with videourodynamic proven detrusor underactivity as the study group and in 10 women with stress urinary incontinence as controls. The expression of zona occuldens-1, E-cadherin in the urothelium, tryptase and apoptosis levels in the suburothelium, β3-adrenoceptor, M2 and M3 muscarinic receptors, P2X3 receptor, and inducible and endothelial nitric oxide synthase were compared between study patients and controls. Study patients included 22 women and 12 men with a mean ± SD age of 56.3 ± 19.7 years, of whom 15 had a history of diabetes. Study patients had significantly lower E-cadherin expression, and a higher number of mast cells and apoptotic cells than controls. Additionally, lower expression of M2 and M3 muscarinic receptors, P2X3 receptors and endothelial nitric oxide synthase was detected in study patients but higher expression of β3-adrenoceptor. In study patients a positive correlation was noted between tryptase and apoptosis levels (r= 0.527) and between the expression of M2 muscarinic receptor and P2X3 receptor (r = 0.403). However, β3-adrenoceptor expression negatively correlated with E-cadherin expression (r = -0.490, each p <0.05). Urothelial dysfunction, increased suburothelial inflammation and altered sensory protein expressions in bladder mucosa were prominent in patients with detrusor underactivity. Impaired urothelial signaling and sensory transduction pathways appear to reflect the pathophysiology of detrusor underactivity.

The expression of β3-adrenoceptors and their function in the human prostate.

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. 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. 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. 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.

The expression of β3-adrenoceptor and muscarinic type 3 receptor immuno-reactivity in the major pelvic ganglion of the rat.

Bladder afferent outflow, linked to sensation, plays a critical role in bladder pathology: abnormal outflow results in altered sensation, leading to increased voiding frequency, urge and often incontinence. β3-adrenoceptor agonists have been suggested to be beneficial in treating these symptoms. However, the absence of a significant sympathetic innervation of the detrusor and only a modest relaxation of bladder muscle by β3 agonists has questioned the therapeutic site of action of β3 agonists in the bladder. The present study was done to explore the possibility that β3-adrenoceptors might be located in the pelvic plexus. Using the rat, where the pelvic plexus is located primarily within a single ganglion, the major pelvic ganglion (MPG), immuno-histochemical approaches were used to identify structures expressing β3-adrenoceptor immuno-reactivity (β3AR-IR). The only structures found to express β3AR-IR were small-diameter tyrosine hydroxylase and vesicular mono-amine transporter immuno-reactive (TH-IR and vmat-IR) neurones. These neurones, found in clusters or singly on the periphery of the ganglion, or dispersed in smaller clumps throughout the MPG, are similar to the small intensely fluorescent (SIF) cells described previously. Not all small cells expressed β3AR-IR. A population of the small cells were also immuno-reactive to the type 3 muscarinic receptor (M3R-IR) and the P2X3 purinergic receptor (P2X3-IR). Clumps of small cells were associated with calcitonin gene-related peptide immuno-reactive (CGRP-IR) nerve fibres (putative sensory fibres) and a small number were contacted by putative cholinergic nerves expressing immuno-reactivity to vesicular acetylcholine transporter (vacht-IR). These observations are consistent with the idea that small cells are interneurons and one of the components making up complex neural circuits within the MPG. The precise physiological role of these neural elements in the MPG is unknown. However, as one therapeutic action of β3-adrenoceptor agonists is to modulate sensation, it is possible that these neural circuits may be involved in the regulation of afferent outflow and sensation.

Enhanced Expression of β3-Adrenoceptors in Cardiac Myocytes Attenuates Neurohormone-Induced Hypertrophic Remodeling Through Nitric Oxide Synthase

β1-2-adrenergic receptors (AR) are key regulators of cardiac contractility and remodeling in response to catecholamines. β3-AR expression is enhanced in diseased human myocardium, but its impact on remodeling is unknown. Mice with cardiac myocyte-specific expression of human β3-AR (β3-TG) and wild-type (WT) littermates were used to compare myocardial remodeling in response to isoproterenol (Iso) or Angiotensin II (Ang II). β3-TG and WT had similar morphometric and hemodynamic parameters at baseline. β3-AR colocalized with caveolin-3, endothelial nitric oxide synthase (NOS) and neuronal NOS in adult transgenic myocytes, which constitutively produced more cyclic GMP, detected with a new transgenic FRET sensor. Iso and Ang II produced hypertrophy and fibrosis in WT mice, but not in β3-TG mice, which also had less re-expression of fetal genes and transforming growth factor β1. Protection from Iso-induced hypertrophy was reversed by nonspecific NOS inhibition at low dose Iso, and by preferential neuronal NOS inhibition at high-dose Iso. Adenoviral overexpression of β3-AR in isolated cardiac myocytes also increased NO production and attenuated hypertrophy to Iso and phenylephrine. Hypertrophy was restored on NOS or protein kinase G inhibition. Mechanistically, β3-AR overexpression inhibited phenylephrine-induced nuclear factor of activated T-cell activation. Cardiac-specific overexpression of β3-AR does not affect cardiac morphology at baseline but inhibits the hypertrophic response to neurohormonal stimulation in vivo and in vitro, through a NOS-mediated mechanism. Activation of the cardiac β3-AR pathway may provide future therapeutic avenues for the modulation of hypertrophic remodeling.

Effects of right stellate ganglion block on expression of .BETA.3-adrenoceptor in rabbits with heart failure

Objective To evaluate the effects of the right stellate ganglion block on the expression of β3adrenoceptor (β3-AR) in rabbits with heart failure.Methods Forty-eight Japanese white rabbits of both sexes,weighing 2.5-3.0 kg,were randomly divided into 3 groups (n =16 each):sham operation group (group S),heart failure group (group HF) and right stellate ganglion block group (group RSGB).Heart failure was induced by occlusion of left anterior descending branch of coronary artery and confirmed by ultrasonic cardiography 4 weeks later.A PE-10 catheter was inserted into the right stellate ganglion for administration of drugs.0.25％ bupivacaine 2 ml was injected through the catheter once a day for 2 weeks in group RSGB,while the equal volume of normal saline was injected instead of bupivacaine in S and HF groups.The left ventricular end-diastolic diameter (LVEDD),left ventricular end-systolic diameter (LVESD),ejection fraction (EF) and left ventricular fractional shortening (LVFS) were measured at 1 day before ligation (T0),before catheter insertion (T1),before 8th administration (T2),and 1 day after the last administration (T3).Eight rabbits were sacrificed at T1 and T3 in each group and myocardial specimens were obtained from the apex of the left ventricle for determination of the expression of β3-AR by Western blot.Results Compared with group S,the LVEDD and LVESD were significantly enlarged and LVEF and LVFS were decreased at T1-3,and the expression of β3-AR was up-regulated at T1,3 in groups HF and RSGB (P ＜ 0.05).Compared with group HF,the LVEDD and LVESD were significantly decreased,LVEF and LVFS were increased,and the expression of β3-AR was significantly down-regulated at T3 in group RSGB (P ＜ 0.05).Conclusion The right stellate ganglion block can improve the cardiac function of rabbits with heart failure through down-regulating the expression of β3-AR in myocardium. Key words: Stellate ganglion ; Nerve block ; Heart failure ; Heart function tests; Receptors, adrenergic, beta-3

Pharmacological profile of the selective β3-adrenoceptor agonist mirabegron in cynomolgus monkeys

Mirabegron is a novel β3-adrenoceptor agonist developed for the treatment of overactive bladder. To clarify the relationship between the pharmacological effects of mirabegron in monkeys and the clinical efficacy in patients with overactive bladder, the effect of mirabegron on bladder function was evaluated using cynomolgus monkeys. Quantitative PCR revealed that mRNA expression of β3-adrenoceptors was most abundant (98%) among β-adrenoceptor subtypes in the bladder of cynomolgus monkeys. Mirabegron, which showed selective and potent agonistic activity on monkey β3-adrenoceptors expressed in Chinese hamster ovary cells with EC50 value of 32nmol/L and intrinsic activity of 0.8, induced concentration-dependent relaxation of bladder smooth muscle strips isolated from cynomolgus monkeys with EC50 values of 120nmol/L in 20mmol/L KCl stimulation and 43nmol/L under 9.81 mN resting tension. In conscious cynomolgus monkeys, mirabegron decreased micturition frequency at oral doses of 1 and 3mg/kg and increased mean volume voided per micturition at an oral dose of 3mg/kg. Plasma concentration at which bladder function improved in the cynomolgus monkeys was similar to that at the clinically effective dose in patients with overactive bladder. These data suggest that the relaxant function in monkey bladder is mainly mediated by β3-adrenoceptors similar to that in the human bladder and mirabegron showed efficacy on the bladder functions of the same parameters in clinical evaluation endpoints.

Relationship between the Autoantibody and Expression of β3-Adrenoceptor in Lung and Heart

BackgroundEvidences suggest that β3 -adrenoceptor (β3-AR) plays an important role in heart failure (HF), although no data is reported indicating how these effects may change with the increasing age. Pulmonary congestion and edema are the major life-threatening complications associated with HF. The purpose of this study is to explore the relationship between the anti-β3-AR autoantibody and the expression of β3-AR in the lungs and heart for both aged patients and rats with HF.MethodsSynthetic β3-AR peptides served as the target antigens in ELISA were used to screen the anti-β3-AR autoantibody in aged patients and rats. Two aged rat models were constructed based on aortic banding and sham-operation. The expression of β3-AR mRNA and protein in the lung and heart was measured in intervention and non-intervention groups by Western blot analysis at the baseline, 5th, 7th, 9th and 11th week, respectively.ResultsThe frequency and titer of anti-β3-AR autoantibody in aged patients and rats with HF were higher than those in the control group (p<0.05). The expression of β3-AR mRNA and protein in pulmonary tissues decreased continually from the 7th week (p<0.05), followed by HF observed during the 9th week. The expression of β3-AR in myocardial tissues continued to increase after the 9th week (p<0.05), and the expression of both β3-AR mRNA and protein in the BRL group [HF group with BRL37344 (4-[-[2-hydroxy-(3-chlorophenyl)ethyl-amino] phenoxyacetic acid) (a β3-AR agonist) injection] was positively correlated with BRL37344 when compared with non-BRL group (HF group without BRL37344 injection) (p<0.05).ConclusionAnti-β3-AR autoantibody was detected in aged patients and rats with HF. The expression of β3-AR mRNA and protein in pulmonary tissues decreased continually, and began earlier than in the heart, but its expression in myocardial tissues increased continually and could be further promoted by β3-AR agonist.

Molecular and functional characteristics of β3-adrenoceptors in late pregnant mouse uterus: A comparison with β2-adrenoceptors

β3-adrenoceptor is a potential target for uterine relaxant drugs for the treatment of preterm labor. Mouse is an ideal experimental model for preterm labor. However, there is limited information on the molecular and functional characteristics of β3-adrenoceptors in mouse uterus. Therefore, the current study was undertaken to characterize the β3-adrenoceptors in late pregnant mouse uterus by molecular and functional experiments and to compare their expression and function with the β2-adrenoceptors. Using RT-PCR, we demonstrated the presence of β3-adrenoceptor mRNA in the mouse uterus. Accordingly, selective β3-adrenoceptor agonist SAR150640 (ethyl-4-{trans-4-[((2S)-2-hydroxy-3-{4-hydroxy-3[(methylsulfonyl)amino]-phenoxy}propyl)amino]cyclohexyl}benzoate hydrochloride) caused concentration-dependent relaxation of the isolated tissue. SR59230A (1μM), a selective antagonist of β3-adrenoceptors, antagonized the relaxant response to SAR150640. Using real-time PCR we found that in comparison to β3-adrenoceptor mRNA, β2-adrenoceptor mRNA is predominantly expressed in the late pregnant mouse uterus. We then assessed the comparative efficiency of different β-adrenoceptor agonists, such as SAR150640, salbutamol and isoprenaline to relax the tissue. SAR150640 (pD2 6.64±0.21, Emax 104.9±7.95), salbutamol (pD2 8.57±0.062, Emax 103.1±3.22) and isoprenaline (pD2 9.48±0.084, Emax 102.9±5.18) caused concentration-dependent inhibition of uterine rhythmic contractions. While the maximal relaxation to these agonists was comparable, the order of potency was isoprenaline>salbutamol>SAR. These results suggest that β3-adrenoceptor mRNA is present in the pregnant mouse uterus and is functionally active. The predominance of β2- over β3-adrenoceptor expression may explain variable potency amongst the β-adrenoceptor agonists.

Relationship between expression of β3‐adrenoceptor mRNA in bladder mucosa and urodynamic findings in men with lower urinary tract symptoms

To investigate the relationship between urinary bladder mucosal expression of β3-adrenoceptor (AR) mRNA and urodynamic findings in patients with lower urinary tract symptoms and benign prostatic obstruction (BPO). During surgical prostate resection of 32 BPO patients, mucosal biopsies were collected and analyzed by reverse transcriptase polymerase chain reaction to determine the expression level of β3-AR mRNA. First desire to void (FDV) and strong desire to void (SDV), detrusor overactivity (DO), and bladder outlet obstruction (BOO) were measured pre-operatively. Patients with FDVs < 200 ml or SDVs < 300 ml were assigned to the small capacity group (n = 19). Patients with FDVs > 201 ml and SDVs > 301 ml were assigned to the large capacity group (n = 13). The same patients with positive DO were also assigned to the DO+ group (n = 11), and those with negative DO were assigned to the DO- group (n = 21). Finally, patients whose position on the Schäfer nomogram was greater than degree V were assigned to the severe BOO group (n = 17), while those with less than degree IV were assigned to the mild BOO group (n = 15). The expression level of β3-AR mRNA was similar in both bladder capacity groups and both DO groups. However, the expression level in the severe BOO group was significantly less than in the mild BOO group (P = 0.043). The expression of bladder mucosal β3-AR mRNA was significantly decreased in patients with severe BOO, suggesting that β3-ARs might be affected by the degree of BOO.

Increased density of sympathetic nerve fibers in metabolically activated fat tissue surrounding human synovium and mouse lymph nodes in arthritis

To investigate the density of sympathetic nerve fibers in and the metabolic activation of fat tissue surrounding human synovium in rheumatoid arthritis (RA)/osteoarthritis (OA) and in the draining lymph nodes of arthritic and normal mice. Using immunofluorescence and immunohistochemistry, the density of sympathetic nerve fibers and the presence of nerve repellent factors were investigated. The metabolic activation of fat tissue was estimated by the occurrence of small-vacuole adipocytes, expression of β3-adrenoceptors, and adipose tissue weight. The density of sympathetic nerve fibers was markedly increased in fat tissue surrounding RA synovium compared with that in fat tissue surrounding OA synovium. In adipose tissue adjacent to draining lymph nodes, the density of sympathetic nerve fibers was higher in arthritic mice compared with normal mice. In human synovium and mouse draining lymph nodes, the 2 sympathetic nerve repellent factors, semaphorin 3C and semaphorin 3F, were highly expressed. In arthritic compared with normal mice, the fat tissue around lymph nodes was markedly lighter, adipocytes had more fragmented lipid droplets, and fat tissue demonstrated high expression of β3-adrenoceptors. This study demonstrated an increased density of sympathetic nerve fibers in metabolically activated fat tissue surrounding human RA synovium and the draining lymph nodes of arthritic mice. Because sympathetic neurotransmitters stimulate lipolysis, the repulsion of sympathetic nerve fibers from inflamed regions and their increased occurrence in fat tissue probably represent an adaptive program to support the proinflammatory process by releasing energy-rich substrates.

Testosterone modulation of cardiac β-adrenergic signals in a rat model of heart failure

In this study, we examined the effects of castration and testosterone replacement on β-adrenoceptor and G protein expression in rats subjected to doxorubicin-induced heart failure. Five groups were included in this report: control, sham-castration with heart failure, castration with heart failure, castration+testosterone replacement with heart failure and castration+testosterone replacement and flutamide with heart failure. At 4 weeks post-treatment, echocardiography, hemodynamics and histopathology were assessed. Castration led to a further deterioration in myocardial performance, apoptosis and fibrosis, while testosterone replacement ameliorated these effects. Data obtained from Western blots revealed that testosterone upregulated the expression of β2-adrenoceptor, Gs, Gi2 and bcl2 levels, downregulated the expression of β3-adrenoceptor, Gi3 and GRK2 levels, and did not modify the expression of β1-adrenoceptor levels in the hearts of castrated rats subjected to doxorubicin-induced heart failure. Analyses of serum 17β-estradiol concentrations test confirmed that these effects of testosterone were exerted through the androgen pathway. Thus our findings suggest that testosterone may have beneficial effects for male heart failure patients with androgen deficiency and this protection involves modulation of the cardiac β-adrenergic system.