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Previous studies have demonstrated that antibodies against cholinoreceptors of exocrine glands correlate with dry mouth in persons with primary Sjögren syndrome (pSS). The aim of the present investigation was to establish if serum IgG antibodies (pSS IgG) were able to interact with cholinoreceptors in rat submandibular gland-dependent stimulation of cyclooxygenase 2 (COX-2) mRNA expression and PGE(2) production. Our findings indicated that pSS IgG-stimulating M(3), M(4), and M(1) cholinoreceptors exerted an increase in COX-2 mRNA without affecting COX-1 mRNA expression and increased PGE(2) production. Inhibitors of phospholipase A(2), COX- s, L-type calcium channel currents, and Ca(2+)-ATPase from sarcoplasmic reticulum prevented the pSS IgG effect on PGE(2) production. An ionophore of calcium mimicked pSS IgG action, suggesting a crucial role of calcium homeostasis in the cholinoreceptor-stimulated increase in PGE(2) production. Moreover, the amounts of PGE(2) in saliva and in sera from persons with pSS were significantly higher than in pre- or post-menopausal women. These findings illustrate the importance of autoantibodies to cholinoreceptors in the generation of chronic inflammation of target tissues in SS. [ABSTRACT FROM AUTHOR]

Background and Objective: Autoimmune mechanisms may contribute to the pathogenesis of periodontal disease. Autoantibodies with the potential to bind and activate β1-adrenoceptors (β1-AR) of human gingival fibroblasts were studied to provide evidence of altered humoral immune response in chronic periodontal disease. Material and Methods: Flow cytometry and enzyme-linked immunosorbent assay using cell culture-adherent gingival fibroblasts and/or their purified membranes and/or a synthetic peptide corresponding to the second extracellular loop of human β1-AR were used to detect serum antibodies. The effects of antibodies from chronic periodontal disease patients on PGE2 generation and CD40 expression were also tested. Results: Circulating immunoglobulin G (IgG) from chronic periodontal disease patients (but not from normal individuals) interacted with the fibroblast surface, activating β1-AR. Atenolol or CGP 20712 (beta 1-AR antagonists) and β1 synthetic peptide inhibited the interaction of IgG with β1-AR. Immunoglobulin G from chronic periodontal disease patients also displayed agonist-like activity associated with specific β1-AR activation, increasing PGE2 generation and CD40 overexpression. The corresponding affinity-purified anti-β1-AR peptide IgG mimicked these effects. Both effects were prevented by inhibition of cyclo-oxygenase. Conclusion: This article supports the participation of humoral immune alterations in chronic periodontal disease resulting in postsynaptic functional deregulation. Overproduction of proinflammatory mediators (PGE2 and CD40 expression) is induced as a consequence of antibody–β1-AR interaction. The PGE2–CD40–IgG axis may play a part in the pathophysiological mechanisms underlying the inflammatory process in chronic periodontal disease. [ABSTRACT FROM AUTHOR]

BACKGROUND AND OBJECTIVE: Autoimmune mechanisms may contribute to the pathogenesis of periodontal disease. Autoantibodies with the potential to bind and activate beta(1)-adrenoceptors (beta(1)-AR) of human gingival fibroblasts were studied to provide evidence of altered humoral immune response in chronic periodontal disease. MATERIAL AND METHODS: Flow cytometry and enzyme-linked immunosorbent assay using cell culture-adherent gingival fibroblasts and/or their purified membranes and/or a synthetic peptide corresponding to the second extracellular loop of human beta(1)-AR were used to detect serum antibodies. The effects of antibodies from chronic periodontal disease patients on PGE(2) generation and CD40 expression were also tested. RESULTS: Circulating immunoglobulin G (IgG) from chronic periodontal disease patients (but not from normal individuals) interacted with the fibroblast surface, activating beta(1)-AR. Atenolol or CGP 20712 (beta 1-AR antagonists) and beta(1) synthetic peptide inhibited the interaction of IgG with beta(1)-AR. Immunoglobulin G from chronic periodontal disease patients also displayed agonist-like activity associated with specific beta(1)-AR activation, increasing PGE(2) generation and CD40 overexpression. The corresponding affinity-purified anti-beta(1)-AR peptide IgG mimicked these effects. Both effects were prevented by inhibition of cyclo-oxygenase. CONCLUSION: This article supports the participation of humoral immune alterations in chronic periodontal disease resulting in postsynaptic functional deregulation. Overproduction of proinflammatory mediators (PGE(2) and CD40 expression) is induced as a consequence of antibody-beta(1)-AR interaction. The PGE(2)-CD40-IgG axis may play a part in the pathophysiological mechanisms underlying the inflammatory process in chronic periodontal disease. [ABSTRACT FROM AUTHOR]

Langerhans cell histiocytosis (LCH) is a rare disorder mainly of children, whose pathogenesis is still unknown. Some studies have demonstrated that LCH lesions produce different cytokines abnormally that may be relevant to the pathogenesis of the disease. The purpose of this study was to investigate interleukin-1 beta (IL-1 beta) and prostaglandin E2 (PGE(2)) levels in saliva from children with different clinical subtypes of LCH. We studied 29 children with LCH: seven unifocal (Group I), seven multifocal (Group II), 15 multisystemic (Group III) and 12 healthy volunteers (Group IV). Salivary IL-1 beta and PGE(2) levels were significantly higher in LCH than in normal children. A multi-comparison test showed significantly (P < 0.001) higher levels of both IL-1 beta and PGE(2) in saliva from Group III compared with Groups II and I. A significant correlation (r = 0.05) between IL-1 beta and PGE(2) concentrations in saliva from each group was determined. Our findings demonstrated an association between high concentrations of salivary IL-1 beta and PGE(2) and advanced stages of the disease. This allows us to suggest that the abnormal amount of these factors in saliva may serve as a risk marker for disease progression. [ABSTRACT FROM AUTHOR]

Background and purpose:Agonists of the M2 muscarinic acetylcholine receptor (mAChR) increase mRNA for this receptor and mRNA for endothelial and neuronal isoforms of NO synthase (eNOS or nNOS). Here we examine the different signalling pathways involved in such events in rat cardiac atria.Experimental approach:In isolated atria, the effects of carbachol on mRNA for M2 receptors, eNOS and nNOS were measured along with changes in phosphoinositide (PI) turnover, translocation of protein kinase C (PKC), NOS activity and atrial contractility.Key Results:Carbachol increased mRNA for M2 receptors, activation of PI turnover, translocation of PKC and NOS activity and decreased atrial contractility. Inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), NOS and PKC prevented the carbachol-dependent increase in mRNA for M2 receptors. These inhibitors also attenuated the carbachol induced increase in nNOS- and eNOS-mRNA levels. Inhibition of nNOS shifted the dose response curve of carbachol on contractility to the right, whereas inhibition of eNOS shifted it to the left.Conclusions and implications:From our results, activation of M2 receptors induced nNOS and eNOS expression and activation of NOS up-regulated M2 receptor gene expression. The signalling pathways involved included stimulation of PI turnover via PLC activation, CaM and PKC. nNOS and eNOS mediated opposing effects on the negative inotropic effect in atria, induced by stimulation of M2 receptors. These results may contribute to a better understanding of the effects and side effects of cholinomimetic treatment in patients with cardiac neuromyopathy.British Journal of Pharmacology (2007) 151, 175–185. doi:10.1038/sj.bjp.0707180; published online 26 March 2007 [ABSTRACT FROM AUTHOR]

Abstract: In this paper, we have determined the effect of both muscarinic acetylcholine receptor (mAChR) and exogenous prostaglandin E2 (PGE2) on PGE2 production and cyclooxygenases (COX) mRNA gene expression on rat cerebral frontal cortex. Carbachol and PGE2 increase endogenous PGE2 production and the COX-1 mRNA levels by activation of PLA2s. The COX-1 and COX-2 activity participated in the production of PGE2 triggered by exogenous PGE2. While in carbachol-PGE2 only COX-1 activity is affected. The specific inhibition of PGE2 receptor was able to impair the increase of endogenous PGE2 production triggered by both carbachol and exogenous PGE2. These results suggest that carbachol-activation mAChR increased PGE2 production that in turn interacting with its own receptor triggers an additional production of PGE2. Both mechanisms appear to occur by using PLA2 signaling system. This data should be able to contribute to understand the involvement of PGE2 in normal brain function and its participation in neuroinflammatory processes. [Copyright &y& Elsevier]

Aim: In this study, we have determined signalling pathways involved in adenosine A1 receptor (A1 receptor)-dependent stimulation of amylase release in rat parotid gland. Methods: Amylase release, binding and cyclic adenosine monophosphate (cAMP) assays, inositol phosphates (IPs) production and nitric oxide synthase (NOS) activity in the presence of cyclopentyl-1,3-dipropylxanthine (CPA) alone or in the presence of different inhibitory drugs were performed. Results: The binding parameters of specific A1 antagonist [3H]-cyclopentyl 1,3-dipropilxanthine ([3H]-DPCPX) in parotid gland membranes show a population of high affinity sites with K d (nm) 0.53 ± 0.06 and Bmax (fmol mg−1 protein) 122.6 ± 10.2. CPA stimulation of A1 receptor exerts an increase in amylase release, IPs accumulation, cAMP production and NOS activity. All these A1 agonist effects were blocked by the A1 receptor antagonist DPCPX. Inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), protein kinase C (PKC), and adenylate cyclase, but not NOS, activities attenuated the CPA stimulatory effect on amylase release. The effect of CPA on amylase release significantly correlated with its action either on cAMP or on IPs accumulation. Conclusion: These results suggest that CPA activation of parotid gland A1 receptor induces a stimulatory effect on amylase release associated with increased production of cAMP and IPs accumulation. The mechanism appears to occur secondarily to stimulation of phosphoinositide turnover via PLC activation. This, in turn, triggers cascade reactions involving CaM and PKC. The CPA stimulation of NOS does not appear to participate in amylase release. [ABSTRACT FROM AUTHOR]

1 The aim of this paper was to determine the different signalling cascades involved in contraction of the rat urinary bladder detrusor muscle mediated via muscarinic acetylcholine receptors (muscarinic AChR). Contractile responses, phosphoinositides (IPs) accumulation, nitric oxide synthase (NOS) activity and cyclic GMP (cGMP) production were measured to determine the reactions associated with the effect of cholinergic agonist carbachol. The specific muscarinic AChR subtype antagonists and different inhibitors of the enzymatic pathways involved in muscarinic receptor-dependent activation of NOS and cGMP were tested. 2 Carbachol stimulation of M3 and M4 muscarinic AChR increased contractility, IPs accumulation, NOS activity and cGMP production. All of these effects were selectively blunted by 4-DAMP and tropicamide, M3 and M4 antagonists respectively. 3 The inhibitors of phospholipase C (PLC), calcium/calmodulin (CaM), neuronal NOS (nNOS) and soluble guanylate cyclase, but not of protein kinase C and endothelial NOS (eNOS), inhibited the carbachol action on detrusor contractility. These inhibitors also attenuated the muscarinic receptor-dependent increase in cGMP and activation of NOS. 4 In addition, sodium nitroprusside and 8-bromo-cGMP, induced negative relaxant effect. 5 The results obtained suggest that carbachol activation of M3 and M4 muscarinic AChRs, exerts a contractile effect on rat detrusor that is accompanied by an increased production of cGMP and nNOS activity. The mechanism appears to occur secondarily to stimulation of IPs turnover via PLC activation. This in turn, triggers cascade reactions involving CaM, leading to activation of nNOS and soluble guanylate cyclase. They, in turn, exert a modulator inhibitory cGMP-mediated mechanism limiting the effect of muscarinic AChR stimulation of the bladder. [ABSTRACT FROM AUTHOR]

IgA was obtained from HlV-infected haemophilic patients and the intracellular signals triggered by its reaction with isolated rat intestinal strips were studied. HIV+IgA stained intestinal microvilli with a granular immunofluorescence pattern and bound to the muscarinic acetylcholine receptor (mAChR), displacing the specific muscarinic cholinergic antagonist QNB in a non-competitive manner. It triggered the signals that are the consequence of mAChR stimulation in the intestine. Thus, it decreased cAMP synthesis and increased guanosine 3':5'-cyclic monophosphate (cGMP) formation and phosphoinositide (PI) turnover of the intestine. In addition, it stimulated prostaglandin E2(PGE2) synthesis by intestinal strips. Through its effect on PGE2 synthesis. HIV+ IgA could have a dual action. On the one hand, it could enhance immunosuppression at a local level, favouring pathogen growth and subsequent intestinal dysfunction. On the other hand, PGE2 could directly increase intestinal motility and electrolyte/fluid loss. Both effects could be involved in intestinal damage in AIDS. [ABSTRACT FROM AUTHOR]

It this study we demonstrate that IgG present in the sera of patients with primary Sjögren's syndrome (PSS) could bind and activate muscarinic acetylcholine receptors (mAChRs) of rat parotid gland. These antibodies were able to inhibit in a non-competitive manner the binding of ³H-quinuclidinyl benzilate (QNB) to mAChRs of purified rat parotid gland membranes. Moreover, IgG from PSS could modify biological effects mediated by mAChR activation; i.e. decrease camp, increase phosphoinositide turnover without affecting cGMP. Atropine and 4-DAMP blocked all of these effects, and carbachol mimicked them, confirming the M3 subtype mAChRs mediated PSS IgG action. Neither binding nor biological effect were obtained with IgG from sera of normal women. The prevalence of cholinergic antibody was 100% in PSS, and was independent of Ro/SS-A and La/SS-B antibodies. It could be concluded that antibody against mAChRs may be another serum factor to be considered in the pathophysiology of the development of PSS. [ABSTRACT FROM AUTHOR]

The effects of chagasic sera containing an antibody (EVI antibody), which reacts with the plasma membrane of striated muscle fibres and endothelial cells, on the inotropic and chronotropic influences of noradrenaline upon isolated rat atria suspended in different media, were explored. Also explored were the action of cocaine, normetanephrine and U-0521 (3′-4′-dihydroxy-2- methyl propiophenone) on the atrial effects of the agonist in preparations immersed in Krebs-Ringer bicarbonate, alone and with the addition of normal human sera or EVI positive human chagasic sera (EVI(+)S). The positive inotropic action of a single dose of noradrenaline (3.0 x 10−7 mol·litre−1) was significantly smaller in spontaneously beating auricles exposed to the EVI(+)S. Cumulative dose-response curves for the agonist showed depression and reduced slope suggesting that EVI(+)S may nihilate the effect of the amine by means of a "noncompetitive-like" mechanism.A similar diminished reactivity towards noradrenaline was found regarding atrial contractile rate. Incubation in a solution with U-0521 enhanced the maximal augmentation of atrial isometric tension evoked by the amine in the three media whereas cocaine failed to elicit significant changes. However, normal human sera not only restored but actually potentiated the inotropic influence of noradrenaline although only in auricles bathed with a solution containing EVI(+)S. None of these three agents altered the reduced chronotropic effect of the agonist exposed to the EVI antibody. Contractile influences on atria paced at single fixed rates were similar to those observed in spontaneously beating preparations. The experimental findings suggest that: a) at the contractile frequencies in the present studies neuronal uptake is neither an important mechanism for terminating the contractile effect of exogenously added noradrenaline, nor a factor involved in the altered action of the agonist in the presence of EVI(+)S; and b) the importance of extraneuronal uptake of noradrenaline became clear after the incubation in a media containing EVI(+)S. It is, therefore plausible to suggest that the EVI antibody might influence the contractile effect of the agonist through a reversible enhancement of extraneuronal uptake. This would in turn modify the interaction between the amine and adrenoceptive sites needed for the full positive inotropic effectiveness of noradrenaline. The possible significance of these findings in the alterations observed in chronic Chagas heart disease is discussed. [ABSTRACT FROM PUBLISHER]