Alterations in nitric oxide synthase activity and expression in submandibular glands of NOD mice.

The non-obese diabetic (NOD) mouse model of autoimmune sialadenitis offers the possibility of studying the L-arginine/nitric oxide signaling pathway in salivary glands in basal and neurotransmitter-stimulated conditions and, thus, of analyzing the neural control of the secretory process in the target organ. The purpose of this study was to explore putative alterations in the activity and expression of nitric oxide synthase (NOS) in submandibular glands of NOD mice in relation to parotid glands and unrelated tissues. Here we report that NOD mice with incipient signs of secretory dysfunction presented a marked decrease in basal and vasoactive intestinal peptide (VIP)-stimulated NOS activity and a differential expression of NOS I in submandibular glands compared to control BALB/c mice. Similar alterations in NOS I were found in parotid glands but not in brain or spleen of NOD mice. No differences between NOD and controls appeared in NOS II and NOS III expression in any of the tissues studied.

Antiviral activity of Sanicula europaea L. extracts on multiplication of human parainfluenza virus type 2.

The antiviral activity of Sanicula europaea L. extracts against human parainfluenza virus type 2 (HPIV-2) was examined. The extract prepared from the leaves of the plant and a fraction separated from the crude extract with gel filtration chromatography were found to inhibit HPIV-2 replication without any toxic effect on Vero cells. The acidic fraction obtained from the crude extract of S. europaea leaves was found to be the most active fraction with plaque inhibition assay at non-cytotoxic concentrations. Unfortunately, antiviral activity was not detected in the molecules purified from the crude ethanol extract of Sanicula leaves.

Inhibition of transcription factor NF-kappaB by sesquiterpene lactones: a proposed molecular mechanism of action.

Many sesquiterpene lactones (SLs) possess considerable anti-inflammatory activity. They inhibit the transcription factor NF-kappaB by selectively alkylating its p65 subunit probably by reacting with cysteine residues. Here we assayed 28 sesquiterpene lactones for their ability to inhibit NF-kappaB. The majority of the potent NF-kappaB inhibitors possess two reactive centers in form of an alpha-methylene-gamma-lactone group and an alpha,beta- or alpha,beta,gamma,delta-unsaturated carbonyl group. Based on computer molecular modelling we propose a molecular mechanism of action, which is able to explain the p65 selectivity of the SLs and the observed correlation of high activity with alkylant bifunctionality. A single bifunctional SL molecule can alkylate the cysteine residue (Cys 38) in the DNA binding loop 1 (L1) and a further cysteine (Cys 120) in the nearby E' region. This cross link alters the position of tyrosine 36 and additional amino acids in such a way that their specific interactions with the DNA become impossible. We also created a model for monofunctional SLs.

Spinonin, a novel glycoside from Ononis spinosa subsp. leiosperma.

The roots of Ononis spinosa subsp. leiosperma (Leguminosae) afforded a new glycoside, spinonin (1), possessing a novel skeleton, in addition to the known isoflavonoid glycoside, ononin [7beta-(glucosyloxy)formononetin] (2) and the known pterocarpan, 7-demethoxy-7-D-(glucosyloxy)homopterocarpin (3). The structure of the new isolate was elucidated by spectral methods including 1H and 13C NMR, COSY, APT, HETCOR, HMBC, NOESY, CD, FABMS, HRMS, EIMS, CIMS, and some chemical reactions. Spinonin was inactive against a number of human cancer cell lines and HIV-1 reverse transcriptase. The compounds 1 and 3 showed weak activity against Pseudomonas aeruginosa, whereas 2 was active against beta-hemolytic Streptococcus.

Cytotoxic and antibacterial activities of sesquiterpene lactones isolated from Tanacetum praeteritum subsp. praeteritum.

Ten sesquiterpene lactones and one sesquiterpene isolated from Tanacetum praeteritum subsp. praeteritum: 1 alpha, 6 alpha -dihydroxyisocostic acid methyl ester (2), 1 alpha-hydroxy-1-deoxoarglanine (3), douglanin (5), santamarin (6), reynosin (7), 1-epitatridin B (8), ludovicin A (10), armexin (12), armefolin (13), armexifolin (14), and 3 alpha-hydroxyreynosin (15) were tested against the human lung carcinoma cell line GLC4 and the colorectal cancer cell line COLO 320 as well as against the bacteria Bacillus subtilis, Staphylococcus aureus, Proteus mirabilis, Escherichia coli, Klebsiella pneumoniae, Pseudomonas aeruginosa, Enterococcus, beta-hemolytic Streptococcus, and the yeast Candida albicans. In addition, two germacranolides tatridin A (16) and tamirin (17) were included in the study. All compounds showed cytotoxic activity (IC50 = 124 microM) but most of them were not effective in the antimicrobial tests.

Increases in cyclic AMP levels couple to H1 receptors in atria from autoimmune myocarditis mice.

We have previously shown that myocardium from experimental autoimmune myocarditis expresses H1 receptors not present in normal mice heart. ThEA acting via H1 receptors, augments cyclic AMP production in atria from autoimmune myocarditis mice without any effect on atria from control mice. Addition of mepyramine before ThEA caused cyclic AMP levels to fall to a level similar to basal, confirming the H1 receptor participation. Histamine at low concentrations mimicked the ThEA action on H1 receptor-stimulation of cyclic AMP production by autoimmune myocardium. The fact that the inhibition of phospholipase C blocked the cyclic AMP stimulation by ThEA, supports the assumption that this action is secondary to receptor-mediated hydrolysis of phosphoinositides, generating some oxidative metabolites (IP3-DAG), which in turn may be responsible for the cyclic AMP effect. So, the inhibition of protein kinase C and calcium/calmodulin partially prevented the stimulatory action of ThEA on cyclic AMP levels in autoimmune myocardium, suggesting that both pathways are implicated in this effect. Data shows that the stimulation of H1 receptors by specific agonist in atria from autoimmune myocarditis mice, augments the cyclic AMP, requiring the hydrolysis of phosphoinositide cycle. The role of this cyclic AMP augmentation in myocardium from autoimmune myocarditis mice, will provide a basis to assess the role of this second messenger as an important factor in the regulation and/or modulation of the physiological behaviour of the heart in the course of autoimmune myocarditis.

Effect of histamine in autoimmune myocarditis mice.

The contractile effect of histamine, as well as the H1 receptor population and H2 receptor-mediated cAMP production, were measured in cardiac tissue from control normal and autoimmune myocarditis mice. Histamine triggered positive chronotropy and negative inotropy at high concentrations in both control and autoimmune auricles, H2 receptors being the most important mediator of these responses. In contrast, in atria from autoimmune myocarditis mice, histamine at lower concentrations caused positive inotropy and negative chronotropy. These effects, not verified in the normal control atria, are mediated by H1 receptors. The expression of H2 and H1 receptors mediating the cardiac response to histamine was evaluated through histamine-stimulated cAMP level and binding of [3H] mephyramine, respectively. Both control and autoimmune myocardium were able to increase cAMP levels, an effect that was inhibited by H2 antagonist drug. The amount of cAMP was significantly higher in control myocardium than in those from autoimmune ones. Saturable binding of [3H] mephyramine occurs in autoimmune myocardium, with distinct high and low affinity binding sites. In control myocardium non-saturable binding was detected. These results suggest that H1 and H2 receptors coexist in heart from autoimmune myocarditis mice, whereas only H2 receptors are present in myocardium from control mice. The presence of H1 receptors in autoimmune myocardium could be an important factor in the regulation of its physiological behaviour.

Expression of histamine H1 receptors in autoimmune myocarditis mice.

Two populations of histaminergic H1 receptors with distinct high and low affinity binding sites were characterized by the specific H1 receptor antagonist [3H]mepyramine in autoimmune myocardium. No saturable binding of the radiolabelled H1 antagonist was observed in normal myocardium. Reaction of autoimmune myocardium with specific H1 agonist (2-thiazolylethylamine (ThEA)) triggered positive inotropy and negative chronotropy, which were inhibited by mepyramine. Inhibitors of phospholipase C and protein kinase C attenuated both the inotropic and chronotropic effects of ThEA, suggesting the participation of phosphoinositide hydrolysis in this phenomenon. The latter was verified by measurement of polyphosphoinositide hydrolysis in autoimmune myocardium following the reaction of ThEA with histaminergic H1 receptors. We conclude that functional H1 histaminergic receptors could involve a distinctive mechanism operating in autoimmune myocardium as a result of cardiac antigen immunization.