Association of Anti-β 1 and Anti-M2 Antibodies with Autonomic Nervous System Modulation in Patients with Chronic Chagas Cardiomyopathy

Abstract Background: Different immune mechanisms of myocardial damage involved in the pathophysiology of Chagas disease coexist with high titers of autoantibodies induced by T. cruzi . There are few studies in the literature about the adaptive role of anti-β1 and anti-M2 antibodies in chronic Chagas cardiomyopathy (CCC). Objectives: To evaluate the association between anti-β1 and anti-M2 antibodies with heart rate variability (HRV) parameters on 24h Holter monitoring and the rate-pressure product (RPP) on cardiopulmonary exercise testing (CPET). Methods: Anti-β1 and anti-M2 antibody titers were measured by enzyme-linked immunosorbent assay (ELISA) in 64 patients affected by CCC. Analysis of HRV was performed through the time-domain indices NNs, mean NN, SDNN, SDANN, SDNN index, NNNs, RMSSD, and pNN50. Spearman's correlation coefficient was used to assess the association between antibody titers and numerical variables. The Mann-Whitney test was used for comparison between two groups. Multiple linear regression was used to identify independent variables capable of explaining anti-β1 and anti-M2 antibody titers at the 5% significance level. Results: On 24h Holter, during the period of greatest parasympathetic activation (2:00-6:00 a.m.), an inverse association was found between anti-β1 titers and SDNN (rs=-0.13, p =0.041, n=43), as well as a direct association between anti-M2 titers and SDANN ( r s=0.317, p =0.039, n=43). Regarding CPET variables, anti-β1 titers were directly associated with RPP (rs=0.371, p =0.005, n=56). The subgroup of patients with a normal chronotropic response showed higher anti-β1 titers than the subgroup with an impaired response (p=0.023). RPP was an independent explanatory variable for anti-β1 titers, although with a low coefficient of determination (R2=0.147). Conclusion: The findings of this study suggest that, in patients with CCC, anti-β1 and anti-M2 antibodies may affect HRV parameters. RPP was directly associated with higher anti-β1 titers.

Expression of autoantibody against the M2-muscarinic receptor in patients with severe preeclampsia / 中南大学学报(医学版)

OBJECTIVE@#To test the expression of autoantibody against the M2-muscarinic receptor in patients with severe preeclampsia.
@*METHODS@#A case-control study, including 78 patients with severe preeclampsia and 78 women with normal pregnancy in Department of Gynaecology and Obstetrics of Capital Medical University affiliated Beijing Chao-Yang Hospital from Jan, 2013 to Jan, 2015, were conducted, and 60 non-pregnant women were served as a control group. ELISA protocol was used to test serum autoantibody against the M2-muscarinic receptor. The clinical significance of the autoantibody against the M2-muscarinic receptor among women with severe preeclampsia was estimated.
@*RESULTS@#Autoantibody against the M2-muscarinic receptor were positive in 32.1% (25/78) of patients with severe preeclampsia, in 10.3% (8/78, P<0.05) of normal pregnant women and in 8.3% (5/60, P<0.05) of non-pregnant controls. The concentration of creatine kinase in patients with severe preeclampsia and normal pregnant women were (101.49±142.75) and (57.94±31.64) U/L,
respectively. Mask difference exist between the severe preeclampsia group and the normal pregnancy group (P<0.05).
@*CONCLUSION@#The expression of autoantibody against the M2-muscarinic receptor in patients with severe preeclampsia is elevated significantly, which is associated with severe preeclampsia. However, its etiological role needs further to be investigated.

Abnormal Sensory Protein Expression and Urothelial Dysfunction in Ketamine-Related Cystitis in Humans / 대한배뇨장애요실금학회지

PURPOSE: The aim of this study was to analyze patterns of sensory protein expression and urothelial dysfunction in ketamine-related cystitis (KC) in humans. METHODS: Biopsies of bladder mucosa were performed in 29 KC patients during cystoscopy. Then specimens were analyzed for tryptase, zonula occludens-1 (ZO-1), E-cadherin, and terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling (TUNEL) with immunofluorescence staining and quantification. In addition, 10 healthy control bladder specimens were analyzed and compared with the KC specimens. Another 16 whole bladder specimens obtained from partial cystectomy were also analyzed for the muscarinic receptors M2 and M3, endothelial nitric oxide synthase (eNOS), inducible nitric oxide synthase (iNOS), β-3 adrenergic receptors (β3-ARs), and the P2X₃ receptor by western blotting. In addition, 3 normal control bladder specimens were analyzed and compared with the KC specimens. RESULTS: The KC bladder mucosa revealed significantly less expression of ZO-1 and E-cadherin, and greater expression of TUNEL and tryptase activity than the control samples. The expression of M3 and β3-AR in the KC specimens was significantly greater than in the controls. The expression of iNOS, eNOS, M2, and P2X3 was not significantly different between the KC and control specimens. CONCLUSIONS: The bladder tissue of KC patients revealed significant urothelial dysfunction, which was associated with mast-cell mediated inflammation, increased urothelial cell apoptosis, and increased expression of the M3 and β3-AR.

AduoLa Fuzhenglin down-regulates microwave-induced expression of β1-adrenergic receptor and muscarinic type 2 acetylcholine receptor in myocardial cells of rats / 生物医学与环境科学（英文）

This paper is aimed to study the effect of ADL on expression of β1-AR and M2-AchR in myocardial cells of rats exposed to microwave radiation. Immunohistochemistry, Western blot and image analysis were used to detect the expression of β1-AR and M2-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 β1-AR and M2-AchR is down-regulated in myocardial cells of rats exposed to microwave radiation. ADL can protect rats against microwave-induced heart tissue injury.

Relaxing Effect of Acetylcholine on Phenylephrine-Induced Contraction of Isolated Rabbit Prostate Strips Is Mediated by Neuronal Nitric Oxide Synthase

PURPOSE: The location of acetylcholinesterase-containing nerve fibers suggests a role for acetylcholine in both contractility and secretion in the prostate gland. The colocalization of nitrergic nerves with cholinergic nerves, and the cotransmission of nitric oxide with acetylcholine in cholinergic nerves, has been demonstrated in the prostate glands of various species. Thus, we investigated the effects of acetylcholine on phenylephrine-induced contraction and the correlation between cholinergic transmission and nitric oxide synthase by using isolated prostate strips of rabbits. MATERIALS AND METHODS: Isolated prostate strips were contracted with phenylephrine and then treated with cumulative concentrations of acetylcholine. Changes in acetylcholine-induced relaxation after preincubation with NG-nitroarginine methyl ester, 7-nitroindazole, and aminoguanidine were measured. The effects of selective muscarinic receptor antagonists were also evaluated. RESULTS: In the longitudinal phenylephrine-contracted strip, the cumulative application of acetylcholine (10(-9) to 10(-4) M) elicited a concentration-dependent relaxation effect. Acetylcholine-induced relaxation was inhibited not only by nitric oxide synthase inhibitors (10 microM L-NAME or 10 microM 7-nitroindazole) but also by 10 microM atropine and some selective muscarinic receptor antagonists (10(-6) M 11-([2-[(diethylamino)methyl]-1-piperdinyl]acetyl)-5,11-dihydro-6H-pyrido[2,3-b][1,4]benzodiazepine-6-one and 10(-6) M 4-diphenylacetoxy-N-methyl-piperidine). In contrast, relaxation was significantly increased by pretreatment of the strips with 10 mM L-arginine. CONCLUSIONS: Acetylcholine relaxed phenylephrine-induced contractions of isolated rabbit prostate strips. This relaxation may be mediated via both cholinergic and constitutive nitric oxide synthase with both the M2 and M3 receptors possibly playing key roles.

Respiratory syncytial virus infection enhances airway hyperresponsiveness in guinea pigs and the underlined mechanism / 中国应用生理学杂志

<p><b>AIM</b>To study the relation between Respiratory Syncytial Virus infection and asthma development by measuring airway responsiveness (AR) and M2R function.</p><p><b>METHODS</b>Guinea pigs (n = 34) were randomly divided into 4 groups: Hep-2/NS group (group A, n = 9), RSV/NS group (group B, n =9), Hep-2/OVA group (group C, n = 8) and RSV/OVA group(group D, n = 8). On day 21 after infection we tested AR and M2R. Then counted eosinophils in BALF and observed pathological change.</p><p><b>RESULTS</b>Intraairway pressure(IP mmH20) of group B had no significant difference with group A(P > 0.01), and the extent of IP decrease also had no difference between groups A and B (P > 0. 05), but IP of C group were much higher than group A (P<0.05), with extent of IP decrease lower than group A (P < 0.05). And IP of group D were higher than group C (P < 0.01), with the extent of IP decrease much lower than group C (P < 0.05).</p><p><b>CONCLUSION</b>RSV infection could enhance OVA-induced M2R dysfunction, then develop AHR.</p>

Variation of M3 muscarinic receptor expression in different prostate tissues and its significance

To detect the expression of the muscarinic receptor [M receptor] in different prostate tissues and analyze the role of its subtype in prostatic oncogenesis. Thirty-six cases of normal prostate and benign prostatic hyperplasia, and 8 cases of prostatic tumor, were used in this study from the Shandong University, Shandong, China, between 2003-2006. The protein expressions of M1, M2, and M3 receptors in each group were determined by Western-blotting. The gene expressions of the M3 receptor and vascular endothelial growth factors [VEGF] in each group were determined by reverse transcriptase-polymerase chain reaction. The protein and gene expressions of the M3 receptor in the prostatic carcinoma group were higher than that of benign prostatic hyperplasia group [p=0.0001] and normal prostate group [p=0.0001]. The M3 receptor and VEGF showed positive straight-line correlations of gene expressions with the 3 groups [r=0.4999, p=0.0001]. The M3 receptor may have a close relationship with prostatic oncogenesis

The relation between positive rate of autoantibodies against beta1 and M2-adrenergic receptors and urinary albumin excretion rate in the type 2 diabetes mellitus with refractory hypertension / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the relation between the positive rates of autoantibodies against beta(1) adrenergic receptor (beta1-receptor)and (M2-receptor) with urinary albumin excretion rate (UAER) in type 2 diabetes patients with refractory hypertension.</p><p><b>METHODS</b>Autoantibodies against beta(1)- and M(2)-receptor as well as autoantibodies were determined in type 2 diabetes patients with (n = 136) or without (n = 111) refractory hypertension, hypertensive patients without renal failure (n = 60) and healthy control subjects (n = 40, control) by ELISA.</p><p><b>RESULTS</b>The positive rates of the autoantibodies against beta1-receptors (44.9%) and M(2)-receptor (37.5%) in patients with type 2 diabetes with refractory hypertension were significantly higher than those in patients with type 2 diabetes without refractory hypertension (27.9% and 24.3%, respectively, all P < 0.05), in patients with hypertension without renal failure (11.7% and 15.0%, all P < 0.01) and in healthy controls (8.3% and 7.5%, all P < 0.01). In type 2 diabetes patients with refractory hypertension and renal failure (UAER > or = 200 microg/min), the positive rates of the autoantibodies against beta(1)-receptor (87.1%, 27/31) and against M(2)-receptor (67.7%, 21/31) were significantly higher than those in type 2 diabetes patients with refractory hypertension but without renal failure (UAER 20 - 199 microg /min, 46.7%, 28/60 and 41.7%, 25/60, respectively, all P < 0.05).</p><p><b>CONCLUSION</b>The serum beta(1)- and M (2)-receptor autoantibodies are positively associated with the UAER level and suggest that these autoantibodies against beta(1) and M(2)-receptor may play important roles in the pathogenesis of the type 2 diabetes with refractory hypertension.</p>

Carbachol exhibited positive inotropic effect on rat ventricular myocytes via M₂ muscarinic receptors / 生理学报

The present study was aimed to investigate the positive inotropic mechanism of carbachol (CCh) on rat ventricular myocytes. The effects of CCh on L-type calcium current (I(Ca,L)) and Na(+)/Ca(2+) exchange current (I(Na/Ca)) were investigated in isolated rat ventricular myocytes. After loading myocytes with Fura-2/AM, electrically triggered Ca(2+) transient and cell shortening in single myocyte were measured simultaneously using ion imaging system with charge-coupled device (CCD) camera. CCh (100 mumol/L) increased I(Na/Ca) in forward mode from (1.18 +/- 0.57) pA/pF in the control group to (1.65 +/- 0.52) pA/pF (P<0.01) and that in reverse mode from (1.11 +/- 0.49) pA/pF in the control group to (1.53 +/- 0.52) pA/pF (P<0.01), respectively. CCh had no effect on I(Ca,L). The stimulatory effect of CCh on I(Na/Ca) was blocked by application of atropine, a non-selective M muscarinic receptor antagonist, and methoctramine, a selective M(2) muscarinic receptor antagonist. CCh (100 mumol/L) increased cell shortening from (3.00 +/- 0.67) mum in the control group to (3.55 +/- 1.21) mum. Ca(2+) transient was also increased from 203.8 +/- 50.0 in the control group to 234.8 +/- 64.3 in 100 mumol/L CCh group. KB-R7943, a selective inhibitor of reverse mode Na(+)/Ca(2+) exchange, did not change the baseline level of cell shortening and Ca(2+) transient, while completely abolished CCh-induced increments of both Ca(2+) transient and cell shortening. CCh increased cell shortening and Ca(2+) transient in the presence of nicardipine, indicating that the positive inotropic effect of CCh was through activation of Na(+)/Ca(2+) exchange. Calcium sensitivity was not changed by CCh. Both atropine and methoctramine abolished the positive inotropic effects of CCh, demonstrating that CCh induced positive inotropism via the M(2) muscarinic receptor. The results suggest that CCh increases cell contraction and Ca(2+) transient in rat ventricular myocytes. This positive inotropic effect of CCh is through activation of reverse mode Na(+)/Ca(2+) exchange, and M(2) receptors are involved in mediating CCh-induced contraction.

Effects of organophosphorus insecticides on G protein-coupled receptor kinase-2 mediated phosphorylation of M2 muscarinic receptors / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To explore the effect of organophosphorus insecticides (OPs) on G protein-coupled receptor kinase 2 mediated phosphorylation of M2 muscarinic receptors in vitro and to understand an alternative target of the OPs for human and other animals.</p><p><b>METHODS</b>The acetylcholine M2 muscarinic receptors (mAChR2) were purified from rat brain by single step affinity chromatography. In vitro experiments, the purified mAChR2, G-protein coupled receptor kinase 2 (GRK2) and the (gamma-p32) labeled ATP were incubated with paraoxon (PO), chlorpyrifos oxon (CPO) or chlorpyrifos (CPF) of varying concentrations. The proteins were separated by the polyacrylamide gel electrophoresis. The gels were dried and the phosphorylation of mAChR2 was detected with autoradiograms. Bands containing M2 receptor were excised and counted by liquid scintillation.</p><p><b>RESULTS</b>CPO inhibited phosphorylation of M2 muscarinic receptors by GRK2 with a median inhibition concentration (IC(50)) at 70 micromol/L. CPF also inhibited M2 receptors phosphorylation, but was less potent and less efficacious than that of CPO. PO and parathion (PT) had little effect on the receptor phosphorylation under the same conditions. CPO and CPF didn't inhibit the beta2 Adrenalin (beta2-AR) receptor phosphorylation also mediated by GRK2.</p><p><b>CONCLUSION</b>CPO and CPF can selectively inhibit the GRK2 mediated mAChR2 phosphorylation while PO and PT have no this effect.</p>

Autoantibodies against beta1 and M2 receptor in diabetic patients with refractory hypertension / 中华心血管病杂志

<p><b>OBJECTIVE</b>To explore the role of the autoantibodies against M(2)-muscarinic receptor (M(2)-receptor), beta(1)-adrenergic receptor (beta(1)-receptor) in the development of diabetic with refractory hypertension.</p><p><b>METHODS</b>Serum autoantibodies against M(2) and beta(1) were detected by ELISA using synthesized epitopes of the second extracellular loop of M(2) receptor (169 - 193) and beta(1) receptor (197 - 222) in healthy controls (n = 40), diabetic patients (n = 62), diabetic patients with non-refractory hypertension (n = 55) and diabetic patients with refractory hypertension (n = 81).</p><p><b>RESULTS</b>The positive rates of the autoantibodies against M(2) receptor and beta(1) receptor were similar among healthy controls (15.0% and 17. 5%), diabetes mellitus patients (17.7% and 14.5%) and diabetic patients with non-refractory hypertension (16.4% and 12.7%) but are significantly higher in diabetic patients with refractory hypertension (64.2% and 55.6%, P < 0.01 vs. other 3 groups).</p><p><b>CONCLUSION</b>This finding suggests that autoimmune mechanisms might play a role in the pathogenesis of diabetic patients with refractory hypertension.</p>

Effect of serum autoantibodies against the M2 muscarinic acetylcholine receptors from patients with heart failure on L-Type Ca2+ channel activity in guinea pig cardiac myocytes / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effect of serum autoantibodies against the human M(2) muscarinic acetylcholine receptors (M(2)-receptors, Abs) from patients with congestive heart failure on L-Type Ca(2+) channel activity in guinea pig cardiac myocytes.</p><p><b>METHOD</b>Using whole cell patch-clamp technique, we quantitatively measured the ionic intensity and density of L-Type Ca(2+) channel (I(Ca-L)).</p><p><b>RESULTS</b>The M(2)-receptors agonist (carbachol) could decrease the I(Ca-L) peak intensity and density stimulated by isoprenaline from (2111.65 +/- 203.13) pA and (18.83 +/- 1.14) pA/pF to (1230.87 +/- 208.14) pA (P < 0.01) and (10.72 +/- 1.06) pA/pF (P < 0.01). The serum Abs could also decrease I(Ca-L) peak intensity and density [from (1995.21 +/- 195.13) pA and (18.13 +/- 1.03) pA/pF to (636.42 +/- 110.07) pA (P < 0.01) and (5.54 +/- 0.81) pA/pF, P < 0.01]. The M(2)-receptors antagonist, atropine was able to block these effects of carbachol and Abs.</p><p><b>CONCLUSIONS</b>The circulating serum autoantibodies against the M(2)-receptors has similar effect as M(2)-receptors agonist on decreasing the isoprenaline stimulated I(Ca-L) in guinea pig cardiac myocytes and possess negative inotropic effect. These results further suggest that serum autoantibodies against the human M(2) muscarinic acetylcholine receptors may participate in the pathophysiological processes in patients with heart failure.</p>

Comparison of distribution of cholinergic nerves and M2 receptors between rat atria and ventricles / 南方医科大学学报

<p><b>OBJECTIVE</b>To investigate the general pattern of cholinergic nerve distribution and M(2) receptors in adult rat heart.</p><p><b>METHODS</b>Karnovsky-Roots histochemical staining combining point counting method and immunochemical SABC method with image analysis were used to identify the cholinergic nerves and M(2) receptors, respectively, in adult rat heart.</p><p><b>RESULTS</b>Positive staining of cholinergic nerves and M(2) receptors was found in all regions of the rat heart, and the point count of cholinergic nerves in the atria was 4.6 times as much as that in ventricles, and the area of immunoreactive substance for M(2) receptors two-fold higher in the atria than in the ventricles. The point counts of the cholinergic nerves in the medial-layer myocardium were fewer than that in subepicardial and endocardial tissues of the left ventricular free wall. However, M(2) receptors were comparable among the 3 layers of the left free ventricular wall.</p><p><b>CONCLUSION</b>Cholinergic nerves and M(2) receptors are located in both rat atria and ventricles, but their density is much higher in the atria than in the ventricles. Transmural heterogeneity characterizes cholinergic nerve innervation in the left ventricular free wall without significant differences in M(2) receptor density.</p>

Changes of the expression of beta1-adrenergic receptor and M2-muscarinic acetylcholine receptor in rat hearts after high power microwave radiation / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To investigate the effect of high power microwave (HPM) radiation on the expression of beta(1)-adrenergic receptor (beta(1)-AR) and M(2)-muscarinic acetylcholine receptor (M(2)-AchR) in cardiomyocytes.</p><p><b>METHODS</b>S-band HPM device of mean power density 2 approximately 90 mW/cm(2) was used to irradiate 150 healthy Wistar male rats. Immunohistochemistry and image analysis were used to study the pathological characteristics of heart tissue and the expression of beta(1)-AR and M(2)-AchR.</p><p><b>RESULTS</b>Radiation of over 10 mW/cm(2) made myocardial fibers disordered in arrangement, degeneration even sarcoplasm condensation, Pace cells necrosis, and Purkinje cells lysis in a dose-dependent manner (r = 0.968, P < 0.05). beta(1)-AR expression in endocardium, membrane and cytoplasm of myocardium of left ventricle was increased on d1 after radiation, peaked on d3 (P < 0.05) and recovered on d14. M(2)-AchR expression was peaked on d1 (P < 0.01) and recovered on d14.</p><p><b>CONCLUSION</b>Certain degree intensity of HPM radiation may cause heart injury, and increased expressions of beta(1)-AR and M(2)-AchR, which may play an important role in the pathophysiology of heart injury induced by HPM.</p>

Carbachol augments Na/Ca exchange current via M2 muscarinic receptors in guinea pig ventricular myocytes / 生理学报

Stimulation of cardiac mAChRs by carbachol (CCh) produces a biphasic inotropic response. The mechanisms of the positive inotropic response by higher concentration of CCh appear to be paradoxical. This article was aimed to study the mechanism of the positive inotropic effect of CCh in guinea pig ventricular myocytes. The effects of CCh on L-type calcium current (I(Ca)) and Na/Ca exchange current (I(Na/Ca)) were observed in voltage-clamped guinea pig ventricular myocytes by using Axon 200A amplifier. The results showed that CCh (100 micromol/L) increased both forward mode and reverse mode I(Na/Ca) from (1.2+/-0.1) pA/pF to (2.0+/-0.3) pA/pF for forward mode (P<0.01) and from (1.3+/-0.5) pA/pF to (2.1+/-0.8) pA/pF for reverse mode (P<0.01), respectively. CCh had no effect on I(Ca). The stimulating effect of CCh on I(Na/Ca) could be blocked by application of atropine, a nonselective blocker of muscarinic receptors, which means that the stimulating effect of CCh is through the activation of muscarinic receptors. We made a further study by using methoctramine, a selective antagonist of M2 muscarinic receptors. It completely abolished I(Na/Ca) induced by 100 micromol/L CCh, indicating that the effect of CCh on I(Na/Ca) was mediated by M2 muscarinic receptors. It is generally accepted that contraction in cardiac myocytes results from elevation of intracellular Ca2+ concentration. Ca2+ enters the cells through two pathways: L-type Ca2+ channels and, less importantly, reverse mode Na/Ca exchange. The calcium influx via both pathways promotes the contraction of cardiac myocytes. Because CCh had no effect on L-type Ca2+ current, the increase in Na/Ca exchange current might be the main factor in the positive inotropism of CCh. These results suggest that the positive inotropic effect of CCh in guinea pig heart is through stimulation of Na/Ca exchange and is mediated by M2 muscarinic receptors.

Autoantibodies against the myocardial beta1-adrenergic and M2-muscarinic receptors in patients with congestive heart failure / 中华医学杂志(英文版)

<p><b>OBJECTIVE</b>To determine whether autoantibodies against beta(1)-adrenergic and M(2)-muscarinic receptors are related to patients with congestive heart failure (CHF).</p><p><b>METHODS</b>Both synthetic peptides corresponding to amino acids sequence 197-222 and 169-173 of the second extracellular loops of the beta(1) and M(2) receptors were used as antigens to screen sera from 265 patients.188 were congestive heart failure ( CHF) patients with different heart diseases, among them 42 were ischemic cardiomyopathy (ICD) and 52 were idiopathic dilated cardiomyopathy (IDCM) 44 were hypertensive heart disease (HHD) 50 were rheumatic valvular heart disease (RVHD); 77 were controls, among them 36 were simple hypertension and 41 were healthy donors (NC).</p><p><b>RESULTS</b>Positive sera for beta(1)-adrenergic receptor was found in 45.73% (86/188) of CHF patients, while in the controls it was 10.4% (8/77) (P < 0.01); positive sera for M(2)-muscarinic receptor in CHF patients was found in 49.5% (99/188), while in the control it was 11.7% (9/77) (P < 0.01). The positive ratio of autoantibodies against beta(1)-adrenergic and M(2)-muscarinic receptors in CHF patients with cardiac function class II-III (NYHA) were significantly higher than cardiac function class IV. The average titer of autoantibodies against beta(1)-adrenergic and M(2)-muscarinic receptors of the former was significantly higher than the latter; 56.1% of patients with autoantibodies against beta(1)-adrenergic receptor had autoantibodies against M(2)-muscarinic receptor.</p><p><b>CONCLUSIONS</b>Autoantibodies against beta(1)-adrenergic receptor and M(2)-muscarinic receptor were found in sera from heart failure patients with different cardiac diseases. We propose that autoantibodies against beta(1) and M(2) receptors are not only related to the IDCM, but also to cardiac structural and functional changes.</p>

The acute effects of dimethoate on the muscarinic-receptors of rat brains and the relationship between muscarinic-receptors and cholinesterase / 中华劳动卫生职业病杂志

<p><b>OBJECTIVE</b>To study the acute effects of dimethoate on the muscarinic-receptors(M1, M2) in the brain of rats.</p><p><b>METHODS</b>24 Sprague-Dawley rats were divided into 4 groups randomly. They were administered subcutaneously with 0, 25, 50, 100 mg/kg dimethoate, respectively. Brains were removed after 48 hours of administration. Radioligand binding assay was used to determine the density and affinity of M1 and M2 receptors.</p><p><b>RESULTS</b>Rats in the treated group showed low density of M1 and M2 receptors compared with the control rats. The brain M1 receptor density of the rats in the highest dosage group was significantly lower than that in the control group while brain M2 receptors density had a decrease trend with increasing dosage, but the difference showed no significance. However, there were no differences of the affinity of both M1 and M2 among different treated groups. Correlation analysis showed there is positive relationship between cholinesterase activity and density of M1 receptors(r = 0.583, P < 0.01).</p><p><b>CONCLUSION</b>M1 and M2 receptors density decreased with the increasing dosage of dimethoate. It is suggested that the alleviating of cholinergic symptoms may be due to the decrease of M1 and M2 receptors in rat brain.</p>

The Effects of Vecuronium and Pancuronium on the Tension of the Isolated Rat Tracheal Smooth Muscle / 대한마취과학회지

BACKGROUND: Non-depolarizing muscle relaxants have their muscle relaxing effect by competing with acetylcholine (ACh) at the nicotinic receptor level. What are the effects of such muscle relaxants on the tracheal smooth muscle? This present study was set up to address the question as to how vecuronium and pancuronium influence the tracheal smooth muscle. METHODS: Sixty male Sprague-Dawley rat tracheal smooth muscles were isolated at optimal length for isometric force. The preparations were set up in an organ bath containing Tyrode's solution. And isometric force displacement transducer and physiograph were used to record the change in force. After the equilibration period the preparations were contracted with ACh 10(-5) M and carbachol 3x10(-7)M seperately. The preparations were washed with fresh tyrode's solution and allowed to return passively to resting tone. Then the cumulartive effect of ACh (from 3 10(-7) M through 10(-5) M) and carbachol (CCh, from 10(-8) M through 3 10(-6) M) were produced before and after pretreating the preparation with vecuronium (10(-5) M and 10(-6) M) and pancuronium (10(-5) M and 10(-6) M) respectively. Also, we studied the changes of contraction produced by neostigmine before and after pretreatment with vecuronium (10(-5) M and 3 10(-5) M) and pancuronium (3 10(-6) M and 3 10(-5) M). RESULTS: Vecuronium shifted the ACh dose-response curve of the tracheal contraction to the left (p0.05). CONCLUSIONS: Vecuronium inhibits the ACh hydrolyzing enzyme, especially acetylcholinesterase. Therefore it potentiates ACh contraction in the tracheal smooth muscle, but not the CCh contraction, while pancuronium has a different effect in comparison with vecuronium. That is, at a low concentration it reveals an antagonistic effect on the muscarinic M2 receptor and at a higher concentration it has an antagonistic effect on the muscarinic M3 receptor in the tracheal smooth muscle.