Relationship between catecholamine level and gene polymorphism of β1 adrenergic receptor G1165C in children with EV71 infection in hand foot and mouth disease

Objective:To investigate the relationship between the levels of plasma adrenaline and norepinephrine and gene polymorphism of β1 adrenergic receptor G1165 C in children with enterovirus 71(EV71) infection in hand foot and mouth disease(HFMD). Methods:The polymerase chain reaction(PCR) was used to detect the expression of gene polymorphism of β1 adrenergic receptor G1165 C in vitro. The levels of plasma adrenaline and norepinephrine were measured by enzyme-linked immunosorbent assay(ELISA). Results:The plasma norepinephrine level of severe group was significantly higher than the mild group in children with EV71 infection in HFMD(P<0.05); however,the levels of plasma adrenalinein in two groups had no statistical differences(P>0.05); There was no significant difference in the distribution of β1 adrenergic receptor G1165 C genotype and allele between EV71 infection group and healthy control group(P> 0.05). Further analysis of EV71 infection group by dividing it into mild and severe groups showed that there was no significant difference in the distribution of genotype and allele between these two groups as well(P> 0.05). There was no significant difference in the levels of epinephrine and norepinephrine in different genotypes of EV71 infection group(P> 0.05),and in the levels of plasma epinephrine and norepinephrine in the mild and severe groups(P> 0.05). Conclusions:As the disease gets worse,the plasma norepinephrine level has a rising trend in children with EV71 infection in HFMD,which is an important indicator to evaluate the progress of the disease. However,the gene polymorphism of eptor G1165 C have no significant correlation,not only with the susceptibility and severit β1 adrenergic recy of EV71 infection in hand,foot and mouth disease,but also with the levels of catecholamine.

Association of β3 Adrenergic Receptor and Peroxisome Proliferator-activated Receptor Gamma 2 Polymorphisms With Insulin Sensitivity:A Twin Study

Objective To study the effect of β3 adrenergic receptor （β3AR） Trp64Arg and peroxisome proliferator activated receptor gamma 2 （PPAR72） Prol2Ala polymorphisms on insulin resistance. Methods One hundred and eight dizygotic twin pairs were enrolled in this study. Microsatellite polymorphism was used to diagnose zygosity of twins. Insulin sensitivity was estimated with logarithm transformed homeostasis model assessment （HOMA）. PCR-RFLP analysis was performed to detect the variants. As a supplement to the sib-pair method, identity by state （IBS） was used to analyze the association of polymorphisms with insulin sensitivity. Results The genotype frequencies of Trp64Trg, Trp64Arg, and Arg64Arg were 72.3%, 23.8%, and 3.9%, respectively, while the genotype frequencies of Pro12Pro, Pro12Ala, and Ala12Ala were 89.9%, 9.6%, and 0.5%, respectively. For β3AR Trp64Arg the interclass co-twin correlations of Waist-to-hip ratio （WHR）, blood glucose （GLU）, and insulin （INS）, homeostasis model assessment insulin resistance index （HOMA-IR） of the twin pairs sharing 2 alleles of IBS were greater than those sharing 0-1 allele of IBS, and HOMA4R had statistic significance. For PPAR3t2 Prol2Ala most traits of twin pairs sharing 2 alleles of IBS had greater correlations and statistic significance in body mass index （BMI）, WHR, percent of body fat （PBF） and GLU, but there were low correlations of either insulin or HOMA-IR of twin pairs sharing 1 or 2 alleles of IBS. The combined effects of the two variations showed less squared significant twin-pair differences of INS and HOMA-IR among twins sharing 4 alleles of IBS. Condusions β3AR Trp64Arg and PPAR）,2 Pro 12Ala polymorphisms might be associated with insulin resistance and obesity, and there might be slight synergistic effects between this two gene loci, and further studies are necessary to confirm this finding.

The role of α- and β-adrenergic receptors in the spasmolytic effects on rat ileum of Petroselinum crispum Latifolum(parsley)

Objective:To investigate Petroselinum crispum Latifolum(parsley) for treating stomach and intestinal disorders in Iran.Methods:An 80%ethanol extract was prepared from parsley seeds, and its antispasmodic activity assessed by measuring contractions of isolated ilea induced by 60 mM potassium chloride(KG).A piece of ileum from an adult male Wistar rat was dissected and mounted in an organ bath containing Tyrode’s solution,and ileum contractions were recorded by an isotonic transducer under one gram resting tension.The effect of parsley extract was measured in the presence of two antagonists’ of a - and(5-adrenoceptors.Results:These experiments showed that parsley extract inhibited the response to 60 mM KC1 in a concentration-dependent manner(P【0.01,n=7).The spasmolytic effect of parsley extract was unaffected by 1μM phentolamine or 1μM propranolol.Conclusions:This study shows that parsley seed extract is a relaxant of isolated rat ileum and the relaxation effect of extract does not involved adrenergic receptors.

Blocking beta 2-adrenergic receptor inhibits dendrite ramification in a mouse model of Alzheimer's disease

Dendrite ramification affects synaptic strength and plays a crucial role in memory. Previous studies revealed a correlation between beta 2-adrenergic receptor dysfunction and Alzheimer＇s disease （AD）, although the mechanism involved is still poorly understood. The current study investigated the potential effect of the selective β2-adrenergic receptor antagonist, ICI 118551 （ICI）, on Aβ deposits and AD-related cognitive impairment. Morris water maze test results demonstrated that the performance of AD-transgenic （TG） mice treated with ICI （AD-TG/ICI） was significantly poorer compared with NaCl-treated AD-TG mice （AD-TG/NaCl）, suggesting that β2-adrenergic receptor blockage by ICI might reduce the learning and memory abilities of mice. Golgi staining and immunohistochemical staining revealed that blockage of the β2-adrenergic receptor by ICI treatment decreased the number of dendritic branches, and ICI treatment in AD-TG mice decreased the expression of hippocampal synaptophysin and synapsin 1. Western blot assay results showed that the blockage of β2-adrener- gic receptor increased amyloid-β accumulation by downregulating hippocampal a-secretase activity and increasing the phosphorylation of amyloid precursor protein. These findings suggest that blocking the β2-adrenergic receptor inhibits dendrite ramification of hippocampal neurons in a mouse model of AD.

Clinical value of detecting autoantibodies against β1-, β2-, and α1-adrenergic receptors in carvedilol treatment of patients with heart failure

Objective To determine the possible association of anti-β1-adrenergic receptors(anti-β1-AR), anti-β2-AR and anti-α1-AR with carvedilol treatment in patients with heart failure(HF). Methods A total of 267 HF patients were prospectively enrolled. Blood samples were measured by an enzyme-linked immunosorbent assay. All of the patients received carvedilol for their HF. Each patient was followed up for six months and their cardiac function was measured. Results The final analysis encompassed 137 patients comprising 65 patients with three autoantibodies(positive group) and 72 patients without all three autoantibodies but with one or two autoantibodies(negative group). The frequency and geometric mean titer of anti-β1-AR, anti-β2-AR, and anti-α1-AR were significantly lower in the group without all three autoantibodies after six months of carvedilol treatment(all P < 0.01;from 100% to 57%, 50%, and 49%, respectively;and from 1: 118, 1: 138, and 1: 130 to 1: 72, 1: 61, and 1: 67, respectively). Furthermore, 28 patients in the positive group demonstrated complete ablation of autoantibodies. In addition, left ventricular remodelling and function was significantly improved by the use of carvedilol combined with the standard treatment regime for six months in the positive group(P < 0.01) when compared to the negative group(P < 0.05). Conclusions Carvedilol treatment significantly decreases frequency and geometric mean titer in patients with all three autoantibodies, even up to complete ablation, and significantly improved cardiac function and remodelling. The effect of carvedilol is probably correlated to the presence of all three autoantibodies.

Activation of β2 adrenergic receptors promotes adult hippocampal neurogenesis

The subgranular zone (SGZ) of the hippocampal dentate gyrus is one of the few central nervous system regions where generation of adult born neurons occurs physiologically.This process,referred to as adult hippocampal neurogenesis (ahN),relies on the presence of neural progenitor cells (NPC) in the SGZ neurogenic niche.

AduoLa Fuzhenglin Down-regulates Microwave-induced Expression of β_1-adrenergic Receptor and Muscarinic Type 2 Acetylcholine Receptor in Myocardial Cells of Rats

This paper is aimed to study the effect of ADL on expression of ~z-AR and Mz-AchR in myocardial cells of rats exposed to microwave radiation. Immunohistochemistry, Western blot and image analysis were used to detect the expression of ~I-AR and Mz-AchR in myocardial cells at 7 and 14 d after microwave exposure. The results show that the expression level was higher in microwave exposure group and 0.75 g/（kg.d） ADL group than in sham operation group and significantly lower in 1.5 and 3.0 g/（kg.d） ADL groups than in microwave group. So we have a conclusion that the expression of I^z-AR and Mz-AchR is down-regulated in myocardial cells of rats exposed to microwave radiation. ADL can protect rats against microwave-induced heart tissue injury.

β_(2) and α_(2) adrenergic receptors mediate the proneurogenic in vitro effects of norquetiapine

Positive modulation of adult hippocampal neurogenesis may contribute to the therapeutic effects of clinically relevant antidepressant drugs,including atypical antipsychotics.Quetiapine,an antipsychotic which represents a therapeutic option in patients who are resistant to classical antidepressants,promotes adult hippocampal neurogenesis in preclinical studies.Norquetiapine,the key active metabolite of quetiapine in humans,has a distinctive receptor profile than the parent compound.The drug is indeed a high affinity norepinephrine transporter inhibitor and such activity has been proposed to contribute to its antidepressant effect.At present,no information is available on the effects of norquetiapine on adult neurogenesis.We extensively investigated the activity of quetiapine and norquetiapine on adult murine neural stem/progenitor cells and their progeny.Additionally,selective antagonists for β_(2)/α_(2) adrenergic receptors allowed us to evaluate if these receptors could mediate quetiapine and norquetiapine effects.We demonstrated that both drugs elicit in vitro proneurogenic effects but also that norquetiapine had distinctive properties which may depend on its ability to inhibit norepinephrine transporter and involve β_(2)/α_(2) adrenergic receptors.Animal care and experimental procedures were approved by the Institutional Animal Care and Use Committees(IACUC)at University of Piemonte Orientale,Italy(approval No.1033/2015PR)on September 29,2015.

Association between essential hypertension and polymorphisms of beta 1 adrenergic receptor gene G1165C (Gly389Arg) in Chinese Mongolian population

BACKGROUND： The prevalences of hypertension, cerebrovascular diseases, etc. are higher in Mongolian population because of the influence of various factors including genetics, geography, diet, etc. Therefore, it is helpful to develop researches on the genetics of various diseases including hypertension in Mongolian population. OBJECTIVE： To analyze the association between the polymorphism of beta1 adrenergic receptor （β1-AR） gene G1165C （Arg389Gly）, an important candidate gene for various diseases of cardiovascular system, and essential hypertension in Mongolian population. DESIGN ： A cross-sectional study SETTINGS： Department of Neurology, the First Affiliated Hospital of Inner Mongolia Medical College; Wulate Houqi Red Cross Society. PARTICIPANTS： The survey was carried out from February 2003 to March 2005. Totally 239 Mongolian residents, whose blood relations of 3 generations were all Mongolians, were selected from Wulate Houqi, Inner Mongolia, and they were all informed with the survey and detected items. Based on the diagnostic standard of hypertension set by WHO in 1999, the subjects were divided into two groups according to the level blood pressure： ① Normal blood pressure group （n=117）： systolic blood pressure （SBP） 〈 140 mm Hg （1 mm Hg =0.133 kPa）, diastolic blood pressure （DBP） 〈 90 mm Hg, and those having histories of cerebrovascular disease, heart disease, diseases of liver, kidney and tiroides, and diabetes mellitus were excluded. ② Essential hypertension group （n=122）： including 51 patients with simple high SBP. All the enrolled subjects had no blood relationship with each other, and had no history of miscegenation. METHODS ： The body height, body mass, waist circumference and blood lipids were measured routinely, and their habits of smoking and drinking were also investigated. Penpheral venous blood （5 mL） was drawn, the genome DNA was extracted, and the polymorphisms of the β1-AR Gl165C （Gly389Arg） genotype were detected with the Sequenom system. Polymerase chain reaction （PCR） experiment and SNP detection were performed in Huada Gene Laboratory of Bejing, then the univariate analysis of variance was applied in the sample comparison among groups, and the chi-square test was used to compare the genotypes and allele frequencies. The odd ratio （OR） and 95% confidence interval （CO were calculated. MAIN OUTCOME MEASURES： The distributions of β1-AR Gl165C （Gly389Arg） genotypes and alleles were observed. RESULTS： A11 the 239 subjects were involved in the analysis of results, and no one missed, ①Comparison of β1-AR G1165C （Gly389Arg） genotypes and allele distnbutions： In Mongolian population, the frequencies of CC and GG＋GC genotypes at β1-AR G1165C （Gly389Arg） site in the essential hypertension group （72%, 28%） were not significantly different from those in the normal blood pressure group （67%, 33%） （xz=0.841, P=-0.359; OR 0.773, 95%Cl： 0.445-1.342）; The frequencies of C and G alleles also had no significant differences between the essential hypertension group （85%, 15%） and the normal blood pressure group （82%, 18%） （x^2=1.136, P=-0.287; OR： 0.769, 95%Cl： 0.747-1.248）. ②The frequencies of CC and GG＋GC genotypes at β1-AR G1165C （Gly389Arg） site had no significant differences between the patients with simple high SBP （71%, 29%） and the normal blood pressure group （x^2=0.250, P=-0.617; OR： 0.833, 95%C/： 0.408-1.703）; The frequencies of C and G alleles were not significantly different between the patients with simple high SBP （86%, 14%） and the normal blood pressure group （x^2=0.670, P=-0.413; OR 0.766, 95%Cl： 0.404-1.453）. CONCLUSION： In Mongolian population, the distributions of the genotypes and alleles of β1-AR Gl165C （Gly389Arg） have no obvious differences between the subjects with normal blood pressure and the patients with essential hypertension （including simple SBP increase）, which suggests that G1165C （Glu389Asp） site of β1-AR gene may be not a genetic mark of essential hypertension and simple high SBP in Mongolian population.

β-2 Adrenergic receptor gene polymorphism and response to propranolol in cirrhosis

AIM: To evaluate the association of β-2 adrenergic receptor(β2-AR) gene polymorphism with response of variceal pressure to propranolol in cirrhosis.METHODS: Sixty-four non-related cirrhotic patients participated in this study and accepted variceal pressure measurement before and after propranolol administration. Polymorphism of the β 2-AR gene was determined by directly sequencing of the polymerase chain reaction products from the DNA samples that were prepared from the patients.RESULTS: The prevalence of Gly16-Glu/Gln27 and Arg16-Gln27 homozygotes, and compound heterozygotes was 29.7%, 10.9%, and 59.4%, respectively.Patients with cirrhosis with Gly16-Glu/Gln27 homozygotes had a greater decrease of variceal pressure after propranolol administration than those with Arg16-Gln27 homozygotes or with compound heterozygotes(22.4% ± 2.1%, 13.1% ± 2.7% and 12.5% ± 3.1%,respectively, P < 0.01).CONCLUSION: The variceal pressure response to propranolol was associated with polymorphism of β 2-AR gene. Patients with the Gly16-Glu/Gln27 homozygotes probably benefit from propranolol therapy.

Developmental changes in functional expression andβ-adrenergic regulation of If in the heart of mouse embryo

The hyperpolarization-activated current (If) plays an important role in determining the spontaneousrate of cardiac pacemaker cells. The automatic rhythmicity also exists in working cells of embryonic heart,therefore we studied developmental changes in functional expression and β-adrenergic regulation of If inembryonic mouse heart. The expression of If is high in early developmental stage (EDS) (10.5 d after coitus)ventricular myocytes, low in intermediate developmental stage (IDS) (13.5 d) atrial or ventricular myocytesand even lower in late developmental stage (LDS) (16.5 d) atrial or ventricular myocytes, indicating thatthese cells of the EDS embryonic heart have some properties of pacemaker cells. β-adrenergic agonistisoproterenol (ISO) stimulates If in LDS but not in EDS cardiomyocytes, indicating that theβ-adrenergicregulation of If is not mature in EDS embryonic heart. But forskolin (a direct activator of adenylate cyclase)and 8-Br-cAMP (a membrane-permeable analogue of cAMP) increase the amplitude of If in EDS cells,indicating that adenylate cyclase and cAMP function fairly well at early stage of development. Furthermore,the results demonstrate that If is modulated by phosphorylation via cAMP dependent PKA both in EDSand LDS cells.

Expression of hippocampal adrenergic receptor mRNA in a rat model of depression

Adrenergic receptor dysfunction is suggested as a potential cause of hippocampal vulnerability to stress-related pathology. We examined mRNA expression of adrenergic receptor （AR） subtypes α1-AR, α1-AR, and β1-AR in hippocampal subregions （CA1, CA3, dentate gyrus） using in situ hybridization in a depression model induced by chronic unpredictable mild stress and social isolation, α1-AR mRNA expression was significantly increased in the CA3 and dentate gyrus, β1-AR mRNA was significantly increased in the CA1, and α1-AR mRNA remained unchanged in all regions of depression rats compared with controls. Thus, different AR subtypes exhibit a differing pattern of mRNA expression in various hippocampal subregions following depression.

Nitric Oxide Formation Contributes toβ-adrenergic Dilation of Epicardial Coronary Arteries in Response to Intravenous Administration of Dobutamine in Dogs

To examine the role of nitric oxide in the β-adrenergic vasodilation of epicardial coronary arteries in dogs, 12 dogs were instrumented for measurement of left anterior descending coronary artery diameter by transthoracic echocardiography before and after dobutamine (5 μg/kg/min IV) with and without intracoronary infusion of N G-monomethyl-L-arginine (L-NMMA) (1 mg/kg). In all 12 dogs, the diameter of left anterior descending coronary artery increased significantly from 2.35±0.25 mm to 2.59±0.24 mm (P<0.001) after dobutamine administration. In 6 of the 12 dogs, the percent change in left anterior descending coronary artery diameter induced by dobutamine decreased significantly from 12.5%±8.6% to -1.5%±5.4% (P<0.05) after the administration of intracoronary L-NMMA (1 mg/kg for 5 min) to block nitric oxide synthesis from L-arginine. The study demonstrated that nitric oxide formation contributes to the β-adrenergic dilatory response of epicardial coronary arteries to dobutamine in dogs.

Changes of pulmonary α_1-and β-adrenergic receptors after endotoxininduced acute lung injury in rats

Changes of pulmonary α1-and βadrenergic receptors (α1- ARs and β-ARs) after endotoxin-induced lung injury were dynamically observed with radioligand binding assay and the pulmonary rnicrovascular permeability and histopathology were also studied in rats to investigate the relationship between changes of pu1monary ARs and acute lung injury. It was found that the contents of both α1-ARs and β-ARs were significantly decreased after endotoxin-induced acute lung injury. On the basis of these findings, the authors inferred that the down regulation of β-ARs might be one of the factors to increase pulmonary microvascular permeability and that of α1-ARs seems to be a protective reaction. This inference might serve as the theoretical basis to treat pulmonary edema with α1-antagonists and β-agonists clinically.

Effect of Cardiopulmonary Bypass on Beta Adrenergic Receptor Adenylate Cyclase System on Surfaces of Peripheral Lymphocytes

Summary: The experimental results showed that the level of CAMP, the ratio of cAPM to cGMP, IL-2R expression and IL-2 production in vitro in lymphocytes immediate and 2 weeks after car- diopulmonary bypass (CPB) were significantly lower than those before anesthetics in the patients undergoing cardiac surgery with CPB. These findings suggested that CPB could cause serious damage to adrenergic beta receptor-adenylate cyclase system on circulating lymphocytes surfaces, which might be one of the mechanisms resulting in immunosuppression after open heart surgery with CPB.

Association of Polymorphisms of β_3-Adrenergic Receptor,Angiotensinogen and Angiotensin- Converting Enzyme Gene with Hypertension in type 2 DM

ObjectiveTo explore the relationship between the mutant genes of ACE,ATN,β 3 AR and hypertension in patients with type 2 DM. Methods281 recruited Chinese subjects were divided into two groups according to the oral glucose tolerance test (OGTT): ① non diabetes group including normal and impaired glucose tolerance (NGT,IGT): 169 cases;② Type 2 diabetes mellitus (DM): 112 cases. The subjects were genotyped for the ACE gene,the ATN gene and the codon 64 of β 3 AR gene polymorphisms by applying polymerase chain reaction (PCR),PCR restriction fragment length polymorphisms screening with the use of endonuclease. ResultsOur study found that the frequency of D/D genotype and D allele of ACE gene,a/a genotype and an allele of ATN gene in HT patients without DM were increased (P all <0.05);that the frequency of codon 64 mutation of β 3 AR gene also increased in HT patients with NGT (P < 0.05 ). In the model of multiple factors non condition al Logistic regression analyses,HT had relationship with history of hypertension,age and glucose tolerance (OR=10.745 7,1.780 4, 2.034 6;P=0.000 4, 0.000 0 ,0.024 6;respectively),with polymorphism of ATN gene,β 3AR gene,ACE gene (OR= 2.273 6 ,1.935 3,1.830 9;P=0.054 3,0.028 7,0.043 2;resceptively). ConclusionThese results suggest that variants of ACE gene,β 3AR gene,ATN gene were associated with HT in type 2 DM.

Role of β-Adrenergic Signal Transduction Pathway on Myocardial Ischemic Preconditioning of Rats

To study the changes in every part of the β-adrenergic signal transduction pathway and their effects on ischemic preconditioning of rat myocardium in vivo. SD rats were divided into three groups： IP group, I/R group and CON group. The IP group was further divided into PC1-, 2-, 3-, and PC1＋, 2＋, 3＋ groups according to preconditioning procedure. The rats received surgical procedure and underwent left coronary artery occlusion and reperfusion. We analyzed the infarct size by TTC staining, measured serum myocardial enzymes, studied the β-AR Bmax and Kd by radioligand binding assay of receptors, checked the activity of AC and PKA by the method of biochemistry and examined the content of cAMP by radioimmunoassay. The infarct area was much smaller in the IP group than in the I/R group （P〈0. 001）, while the enzymes were significantly higher in I/R （P〈0. 001）. The Bmax of β-AR in IP was much higher than that in I/R （P〈0. 001）, but no difference in Kd could be seen between IP and I/R groups. In IP, the activity of AC and PKA and the content of cAMP were higher than those in I/R （P〈0.05, 0. 002 and 0. 001, respectively）. In the procedure of preconditioning, the content of cAMP and the activity of PKA showed the characteristic of cyclic fluctuation. Ischemic preconditioning can protect the heart from necrosis and reduce endo-enzyme leakage. The system of β-adrenergic signal transduction pathway probably takes part in the protection effect of the IP, which might be elicited by the PKA .

B2 adrenergic receptors and morphological changes of the enteric nervous system in colorectal adenocarcinoma

AIM To study the morphology of the enteric nervous system and the expression of beta-2 adrenergic(B2A) receptors in primary colorectal cancer.METHODS In this study, we included forty-eight patients with primary colorectal cancer and nine patients for control tissue from the excision of a colonic segment for benign conditions. We determined the clinicopathological features and evaluated the immunohistochemical expression pattern of B2 A receptors as well as the morphological changes of the enteric nervous system(ENS). In order to assess statistical differences, we used the student t-test for comparing the means of two groups and one-way analysis of variance with Bonferroni's post hoc analysis for comparing the means of more than two groups. Correlations were assessed using the Pearson's correlation coefficient.RESULTS B2 A receptors were significantly associated with tumor grading, tumor size, tumor invasion, lymph node metastasis(P < 0.05), while there were no statistically significant associations with gender, CRC location and gross appearance(P > 0.05). We observed, on one hand, a decrease of the relative area for both Auerbach and Meissner plexuses with the increase of the tumor grading, and on the other hand, an increase of the relative area of other nervous elements not in the Meissner plexus or in the Auerbach plexus with the tumor grading. For G1 tumors we found that epithelial B2 A area showed an inverse correlation with the Auerbach plexus areas [r(14) =-0.531, P < 0.05], while for G2 tumors, epithelial B2 A areas showed an indirect variation with both the Auerbach plexus areas [r(14) =-0.453, P < 0.05] and the Meissner areas [r(14) =-0.825, P < 0.01]. For G3 tumors, the inverse dependence increased for both Auerbach [r(14) =-0.587, P < 0.05] and Meissner [r(14) =-0.934, P < 0.05] plexuses.CONCLUSION B2 A receptors play an important role in colorectal carcinogenesis and can be utilized as prognostic factors. Furthermore, study of the ENS in colorectal cancer may lead to targeted molecular therapies.

Age-associated alternations in cardiac β-adrenergic receptor signaling

During aging, cardiac contractile response to β-AR stimulation is decreased in humans and animal models. Recent studies demonstrate that the positive inotropic effects of both β1-AR and β2-AR stimulation are significantly decreased with aging.This is accompanied by decreases in both β-AR subtype densities and a reduction in membrane adenylyl cyclase activity. However,neither G protein-coupled receptor kinases (GRKs) nor inhibitory G proteins (Gi) appears to contribute to the age-associated reduction in the β-AR modulation of contraction. Thus, while both aging and chronic heart failure exhibit a diminution in cardiac β-AR responsiveness, only heart failure exhibits increased GRK-mediated desensitization ofβ-Ars and an upregulation of Gi proteins.

Experimental study on alteration of adrenergic receptors activity in neuronal membranes protein of cerebral cortex following brain trau ma in rats

Objective:To definethecourseof changestakenbyα 1 andβadrenergicreceptors(AR)activityaftertraumatic braininjury(TBI)andexploretheapproachforsecondarybraininjury(SBI)management.Methods:Theneuronalmem-braneproteinof cortexwereextractedfromtheratssubjectto traumaticbraininjury,andthechangesofα 1 -andβ-ARac-tivitiesintheneuronalmembraneswereexaminedby radioligandbindingassay(RLBA).Results:α 1 -andβ-ARactivities underwentobviouschanges,reachingtheirpeakvaluesat24h afterTBI.α 1 -ARbindingdensity(B max )reducedby22.6%whiletheligandaffinityincreasedby66.7%,andforβ-AR,however,B max increasedby116.9%andtheligandaffinityre-ducedby50.7%.Theirantagonistscouldcounteractthechangesofα 1 -andβ-ARactivity.Con clu sion:Thepatternsof changesvariesbetweenα 1 -andβ-ARactivityafterTBI, suggestingtheirdifferentrolesintheneuronalmembranesafter braintrauma,andtimelyadministrationof ARantagonistsispotentiallybeneficialinTBImanagement.