Combined In Silico, Ex Vivo, and In Vivo Assessment of L-17, a Thiadiazine Derivative with Putative Neuro- and Cardioprotective and Antidepressant Effects.

Depression associated with poor general medical condition, such as post-stroke (PSD) or post-myocardial infarction (PMID) depression, is characterized by resistance to classical antidepressants. Special treatment strategies should thus be developed for these conditions. Our study aims to investigate the mechanism of action of 2-morpholino-5-phenyl-6H-1,3,4-thiadiazine, hydrobromide (L-17), a recently designed thiadiazine derivative with putative neuro- and cardioprotective and antidepressant-like effects, using combined in silico (for prediction of the molecular binding mechanisms), ex vivo (for assessment of the neural excitability using c-Fos immunocytochemistry), and in vivo (for direct examination of the neuronal excitability) methodological approaches. We found that the predicted binding affinities of L-17 to serotonin (5-HT) transporter (SERT) and 5-HT3 and 5-HT1A receptors are compatible with selective 5-HT serotonin reuptake inhibitors (SSRIs) and antagonists of 5-HT3 and 5-HT1A receptors, respectively. L-17 robustly increased c-Fos immunoreactivity in the amygdala and decreased it in the hippocampus. L-17 dose-dependently inhibited 5-HT neurons of the dorsal raphe nucleus; this inhibition was partially reversed by the 5-HT1A antagonist WAY100135. We suggest that L-17 is a potent 5-HT reuptake inhibitor and partial antagonist of 5-HT3 and 5-HT1A receptors; the effects of L-17 on amygdaloid and hippocampal excitability might be mediated via 5-HT, and putatively mediate the antidepressant-like effects of this drug. Since L-17 also possesses neuro- and cardioprotective properties, it can be beneficial in PSD and PMID. Combined in silico predictions with ex vivo neurochemical and in vivo electrophysiological assessments might be a useful strategy for early assessment of the efficacy and neural mechanism of action of novel CNS drugs.

Effects of 1,3,4-thiadiazine compound with antidepressant properties in ligation model of acute pancreatitis.

Based on hypotheses concerning the role of stress in acute pancreatitis development, the experimental approach for the decrease stress damage via the use the compound with proven antistress/neuroleptic action was conducted. The study was aimed to discover 2-morpholino-5-phenyl-6H-1,3,4-thiadiazine hydrobromide (compound L-17) therapeutic action in experimental acute pancreatitis. The experimental model used was the ligation model. The trial was carried out on 50 male Wistar rats with average body weight 180-240 g. Histological picture of the pancreas was studied and biochemical and enzyme-immunoassays were carried out on the first and seventh days. The significant reduction in mortality on the background of L-17 compound administration was observed. While levels of all cytokines increased in induced experimental acute pancreatitis groups, the cytokine level rise was decreased when compound L-17 was administered. On the cellular level, the study revealed L-17's ability to prevent granulocytosis and decrease granulocytes infiltration to inflammatory foci. The decrease in inflammatory reaction magnitude and prevention of abscess formation in experimental acute pancreatitis accompanied by sistemic inflamamtion was due to L-17's ability to reduce neutrophilia and neutrophil entry into the injury zone.

Immunomodulatory Action of Substituted 1,3,4-Thiadiazines on the Course of Myocardial Infarction.

This review focuses on the biological action of the compounds from the group of substituted 1,3,4-thiadiazines on stress response and myocardial infarction. The aim of this review is to propose the possible mechanisms of action of 1,3,4-thiadiazines and offer prospectives in the development of new derivatives as therapeutic agents. It is known, that compounds that have biological effects similar to those used as antidepressants can down-regulate the secretion of proinflammatory cytokines, up-regulate the release of anti-inflammatory ones and affect cell recruitment, which allows them to be considered immunomodulators as well. The results of pharmacological evaluation, in silico studies, and in vivo experiments of several compounds from the group of substituted 1,3,4-thiadiazines with antidepressant properties are presented. It is proposed that the cardioprotective effects of substituted 1,3,4-thiadiazines might be explained by the peculiarities of their multi-target action: the ability of the compounds to interact with various types of receptors and transporters of dopaminergic, serotonergic and acetylcholinergic systems and to block the kinase signal pathway PI3K-AKT. The described effects of substituted 1,3,4-thiadiazines suggest that it is necessary to search for a new agents for limiting the peripheral inflammatory/ischemic damage through the entral mechanisms of stress reaction and modifying pro-inflammatory cytokine signaling pathways in the brain.

Pharmacologic Evaluation of Antidepressant Activity and Synthesis of 2-Morpholino-5-phenyl-6H-1,3,4-thiadiazine Hydrobromide.

Substituted thiadiazines exert a reliable therapeutic effect in treating stress, and a schematic description of their ability to influence all aspects of a stress response has been depicted. This study was conducted to pharmacologically evaluate compound L-17, a substituted thiadiazine, (2-morpholino-5-phenyl-6H-1,3,4-thiadiazine, hydrobromide) for possible anti-psychotic/antidepressant activity. Compound L-17 was synthesized by cyclocondensation of α-bromoacetophenone with the original morpholine-4-carbothionic acid hydrazide. Pharmacologic evaluations were conducted using methods described by E.F. Lavretskaya (1985), and in accordance with published guidelines for studying drugs for neuroleptic activity. Compound L-17 was evaluated for various possible mechanisms of action, including its effects on cholinergic system agonists/antagonists, dopaminergic neurotransmission, the adrenergic system, and 5-HT3 serotonin receptors. One or more of these mechanisms may be responsible for the beneficial effects shown by thiadiazine compounds in experiments conducted to evaluate their activity in models of acute stress and acute myocardial infarction.

Effect of a new class of compounds of the group of substituted 5R1, 6H2-1,3,4-thiadiazine-2-amines on the inflammatory and cytokine response in experimental myocardial infarction.

This study investigated the effects of the L-17 compound of the group of substituted 5R1, 6H2- 1,3,4-thiadiazine-2-amines on the immune response and the plasma level of circulating cytokines in acute myocardial infarction (MI) in rats. The study was based upon experimental work which demonstrated the role of local and systemic inflammatory reactions in MI. Acute MI in rats was induced by left coronary artery coagulation. Histological study of the myocardium sections has been carried out at the 1(th) and 7(th) days of the experimental myocardial infarction. Serum activity of creatine phosphokinase (CPK), aspartate aminotransferase (AST), isoenzymes 1 and 2 and lactate dehydroge nase (LDH1-2) were investigated at days 1(st)and 7(th). ELISA analysis for plasma cytokine levels was performed using commercially available test kits following the manufacturer's instructions. Biochemical analysis in animals with the administration of the L-17 compound after MI showed that the AST and CPK levels at days 5 and 7 of experiments did not differ significantly from the values of intact animals. In animals of the group with MI without the administration of the L-17 compound, the IL-1 level 8 times and the TNF level 7.8 times exceeded the normal indicators, while the use of L-17 compound in the therapy resulted in only 1.8 times increase of IL-1 level and 4.7 times increase of TNF level in comparison with the norm. Thus, the introduction of L-17 compound in case of experimental MI delays exudative/alternative phase of inflammation, accelerates granulocytic and decreased the inflammation and anti-inflammation interleukins level.

New insights in to the treatment of myocardial infarction.

This study investigated the effects of the L-17 compound of the group of substituted 5R1, 6H2-1,3,4-thiadiazine-2-amines on the inflammatory cellular infiltration and myocardial remodelling which occurs after acute myocardial infarction (MI) in rats. The study is based upon recent clinical and experimental work which demonstrated the role of local and systemic inflammatory reactions in postinfarction remodelling. Acute MI in rats was induced by left coronary artery coagulation. Animals were sacrificed on day one, five and seven after MI induction. The myocardiumal samples were taken from all parts of the heart and examined by histology. This included areas of infarction, infraction and areas that were peri-infarctiom and left ventricular areas distant from the damaged tissues. Serum activity of creatine phosphokinase (CPK), aspartate aminotransferase (AST), isoenzymes 1 and 2 and lactate dehydrogenase (LDH1-2) were investigated on the same three days, before and in the process of MI development was investigated (at days 1, 5 and 7). The L-17 compound to not only decreased the area of initial infarction but also changed the pattern of inflammatory reaction in the affected myocardium fundamentally. Laboratory studies of effects of L-17 compound on the development and course of experimental MI showed that administration decreased blood AST and CPK levels significantly and provided useful the data about the correlation between the activity of these enzymes and the dimensions of the significantly necrotic area. In this model of experimental MI the use of the L-17 compound induced led to the replacement of the exudative destructive inflammation that is seen under standard conditions with a more cellular "productive" pattern of inflammation, with associated reduction in initial necrosis area and the, decrease in myocardial ischaemia and reperfusion injury may account for the accelerated repair process.