Dibenzazepine combats acute liver injury in rats via amendments of Notch signaling and activation of autophagy.

Paracetamol is a commonly used over-the-counter analgesic and antipyretic drug. Nevertheless, an overdose of paracetamol leads to hepatic necrosis that can be lethal. This study aimed to assess the potential hepatoprotective effects of dibenzazepine, a Notch inhibitor, against acute liver injury in rats via interfering with oxidative stress, inflammation, apoptosis, autophagy, and Notch signaling. Silymarin (200 mg/kg, p.o.) or dibenzazepine (2 mg/kg, i.p.) were administered to rats for 5 days before a single hepatotoxic dose of paracetamol (800 mg/kg, i.p.). Pretreatment with silymarin and dibenzazepine significantly mitigated oxidative stress, inflammatory and apoptotic markers induced by paracetamol hepatotoxicity where dibenzazepine showed greater repression of inflammation. Furthermore, dibenzazepine was found to be significantly more efficacious than silymarin in inhibiting Notch signaling as represented by expression of Notch-1 and Hes-1. A significantly greater response was also demonstrated with dibenzazepine pretreatment with regard to the expression of autophagic proteins, Beclin-1 and LC-3. The aforementioned biochemical results were confirmed by histopathological examination. Autophagy and Notch signaling seem to play a significant role in protection provided by dibenzazepine for paracetamol-induced hepatotoxicity in rats, which could explain its superior results relative to silymarin. Graphical abstract.

Targeting γ-secretases protect against angiotensin II-induced cardiac hypertrophy.

OBJECTIVE: The Notch pathway has been linked to pulmonary hypertension, but its role in systemic hypertension and, in particular in left ventricular hypertrophy (LVH), remains poorly understood. The main objective of this work was to analyse the effect of inhibiting the Notch pathway on the establishment and maintenance of angiotensin II (Ang-II)-induced arterial hypertension and LVH in adult mice with inducible genetic deletion of γ-secretase, and to test preclinically the therapeutic efficacy of γ-secretase inhibitors (GSIs). BASIC METHODS: We analysed Ang-II responses in primary cultures of vascular smooth muscle cells obtained from a novel mouse model with inducible genetic deletion of the γ-secretase complex, and the effects of GSI treatment on a mouse cardiac cell line. We also investigated Ang-II-induced hypertension and LVH in our novel mouse strain lacking the γ-secretase complex and in GSI-treated wild-type mice. Moreover, we analysed vascular tissue from hypertensive patients with and without LVH. MAIN RESULTS: Vascular smooth muscle cells activate the Notch pathway in response to Ang-II both 'in vitro' and 'in vivo'. Genetic deletion of γ-secretase in adult mice prevented Ang-II-induced hypertension and LVH without causing major adverse effects. Treatment with GSI reduced Ang-II-induced hypertrophy of a cardiac cell line 'in vitro' and LVH in wild-type mice challenged with Ang-II. We also report elevated expression of the Notch target HES5 in vascular tissue from hypertensive patients with LVH compared with those without LVH. CONCLUSION: The Notch pathway is activated in the vasculature of mice with hypertension and LVH, and its inhibition via inducible genetic γ-secretase deletion protects against both conditions. Preliminary observations in hypertensive patients with LVH support the translational potential of these findings. Moreover, GSI treatment protects wild-type mice from Ang-II-induced LVH without affecting blood pressure. Our results unveil the potential use of GSIs in the treatment of hypertensive patients with LVH.

Cloning and expression of a retinoic acid receptor ß2 subtype from the adult newt: evidence for an early role in tail and caudal spinal cord regeneration.

Retinoic acid receptor beta 2 (RARß2) has been proposed as an important receptor mediating retinoid-induced axonal growth and regeneration in developing mammalian spinal cord and brain. In urodele amphibians, organisms capable of extensive central nervous system (CNS) regeneration as adults, this receptor had not been isolated, nor had its function been characterized. We have cloned a full-length RARß2 cDNA from adult newt CNS. This receptor, NvRARß2, is expressed in various adult organs capable of regeneration, including the spinal cord. Interestingly, both the NvRARß2 mRNA and protein are up-regulated during the first 2 weeks after amputation of the tail, primarily in the ependymoglial and meningeal tissues near the rostral cut surface of the cord. Treatment with LE135, a RARß-selective antagonist, caused a significant inhibition of ependymal outgrowth and a decrease in tail regenerate length. These data support an early role for this receptor in caudal spinal cord and tail regeneration in this amphibian.

Establishment of a rescue program for anorectal malformations induced by retinoic acid in mice.

AIMS OF STUDY: Retinoid-mediated signal transduction plays a crucial role in the embryogenesis of various organs. We previously reported the successful induction of anorectal malformations in mice using retinoic acid (RA). Retinoic acid controls the expression of essential target genes for cell differentiation, morphogenesis, and apoptosis through a complicated interaction in which RA receptors form heterodimers with retinoid X receptors. In the present study, we investigated whether the retinoid antagonist, LE135, could prevent the induction of anorectal malformations (ARMs) in mice. METHODS: Retinoic acid was intraperitoneally administered as 100 mg/kg of all-trans RA on E9; and then the retinoid antagonist, LE135, was intraperitoneally administered to pregnant ICR strain mice on the eighth gestational day (E8), 1 day before administration of RA (group B) or on E9, simultaneously (group C) with RA administration. All of the embryos were obtained from the uteri on E18. Frozen sections were evaluated for concentric layers around the endodermal epithelium by hematoxylin and eosin staining. RESULTS: In group A, all of the embryos demonstrated ARM with rectoprostatic urethral fistula, or rectocloacal fistula, and all of the embryos showed the absence of a tail. In group B, 36% of the embryos could be rescued from ARM. However, all of the rescued embryos had a short tail that was shorter than their hind limb. The ARM rescue rates in group B were significantly improved compared to those in group A (P < .01). In group C, 45% of the embryos were rescued from ARM, but all of the rescued embryos had short tail. The ARM rescue rate in group C was significantly improved compared to that in group A (P < .01). However, there was no significant difference in the ARM rescue rate between group B and Group C. CONCLUSION: The present study provides evidence that in the hindgut region, RAR selective retinoid antagonist, LE135, could rescue embryos from ARM. However, the disturbance of all-trans RA acid was limited to the caudal region. Further study to establish an appropriate rescue program for ARM in a mouse model might suggest a step toward protection against human ARM in the future.

Four new fluorenone alkaloids and one new dihydroazafluoranthene alkaloid from Caulophyllum robustum Maxim.

Four new fluorenone alkaloids, caulophylline A-D (1-4), and one new dihydroazafluoranthene alkaloid, caulophylline E (5) were isolated from the roots of Caulophyllum robustum Maxim. Their structures were elucidated by spectroscopic analysis. Among the isolated alkaloids, Caulophylline E showed good scavenging effects against DPPH radical with IC(50) of 39 µM.

The transcription factors Nur77 and retinoid X receptors participate in amphetamine-induced locomotor activities.

INTRODUCTION: The major substrate underlying amphetamine (AMPH)-induced locomotor activity is associated with dopamine forebrain circuits. Brain regions associated with AMPH-induced locomotor activity express high levels of retinoid receptors. However, the role of these transcription factors in dopamine-mediated effects remains poorly understood. Two nuclear receptor families, the retinoic acid receptors (RAR) and the retinoid X receptors (RXR), transduce retinoic acid signal. RARs are specifically involved in retinoid signaling, whereas RXRs also participate in other signaling pathways as partners for other nuclear receptors such as Nur77, an orphan member of the nuclear receptor family expresses in dopamine system. MATERIALS AND METHODS: To explore the role of retinoid receptors and Nur77 in AMPH-induced locomotor activity, we administered selective retinoid receptor drugs in combination with AMPH in adult wild-type and Nur77-deficient mice. At a low dose, AMPH similarly increased ambulatory activity in wild-type and Nur77-deficient mice, while it did not alter non-ambulatory activity. RESULTS AND DISCUSSION: At a high dose, AMPH did not alter ambulatory activity anymore, while non-ambulatory activity strongly increased in wild-type mice. Nur77-deficient mice still displayed a higher ambulatory activity with no change in non-ambulatory activity. HX531, a synthetic RXR antagonist, blocks AMPH-induced ambulatory activity, whereas RAR drugs tested remained without effect. Interestingly, the effect of HX531 was abolished in Nur77-deficient mice, suggesting that this orphan nuclear receptor is essential for the action of the RXR drug. CONCLUSION: This study shows that RXR and Nur77 participate in AMPH-induced locomotor activity and prompts for further investigations on the role of Nur77 and RXR in addiction and reward-related behaviors.

Ocular anti-allergic compounds selectively inhibit human mast cell cytokines in vitro and conjunctival cell infiltration in vivo.

BACKGROUND: Conjunctival mast cells (MCs) are important effector cells in seasonal allergic conjunctivitis, via histamine and cytokine secretion. Several new anti-allergic eye drops stabilize MCs and block histamine receptors, but their anti-inflammatory effects are unclear. OBJECTIVE: Anti-allergic drugs were compared for their anti-inflammatory effects in an in vitro model of human MC activation and in an experimental murine model of allergic conjunctivitis. METHODS: Human cord blood stem cell-derived (CBMC) and conjunctival biopsy-derived MCs were stimulated via FcepsilonRI, degranulation and histamine release were assayed at 1 h and cytokine secretion at 24 h using multiplex arrays. Mice sensitized to short ragweed pollen were given anti-allergics topically before allergen challenge, and conjunctival immuno-staining was performed at 24 h. RESULTS: After a 1 h stimulation, 80% of the CBMC had degranulated and secreted histamine (27.9+/-4.7 ng/10(6) cells; P<0.05). Pre-treatment by all drugs significantly reduced histamine and TNF-alpha, whereas IL-5, IL-8, IL-10 and TNF-beta profiles were differentially decreased. For conjunctival biopsy-derived cultures (n=11), FcepsilonR1 stimulation increased histamine, TNF-alpha, TNF-beta, IL-5 and IL-8 levels and the production of IL-5, IL-6 (P<0.05), histamine and IL-8 (P<0.01) was inhibited by epinastine. In vivo, epinastine and olopatadine pre-treatment significantly reduced the clinical scores and eosinophil numbers (n=6; P<0.05) while epinastine also reduced neutrophils (P<0.02). CONCLUSION: Differential effects on MC cytokine inhibition were observed, with epinastine inhibiting MC secretion of IL-5, IL-8, IL-10 and conjunctival neutrophil infiltration. The anti-allergic drugs have anti-histamine and mast-cell stabilizing properties but might differ in clinical improvement depending on the individual and the cytokines involved.

Effects of histamine H(1) receptor antagonists on depressive-like behavior in diabetic mice.

We previously reported that streptozotocin-induced diabetic mice showed depressive-like behavior in the tail suspension test. It is well known that the central histaminergic system regulates many physiological functions including emotional behaviors. In this study, we examined the role of the central histaminergic system in the diabetes-induced depressive-like behavior in the mouse tail suspension test. The histamine contents in the hypothalamus were significantly higher in diabetic mice than in non-diabetic mice. The histamine H(1) receptor antagonist chlorpheniramine (1-10 mg/kg, s.c.) dose-dependently and significantly reduced the duration of immobility in both non-diabetic and diabetic mice. In contrast, the selective histamine H(1) receptor antagonists epinastine (0.03-0.3 microg/mouse, i.c.v.) and cetirizine (0.01-0.1 microg/mouse, i.c.v.) dose-dependently and significantly suppressed the duration of immobility in diabetic mice, but not in non-diabetic mice. Spontaneous locomotor activity was not affected by histamine H(1) receptor antagonists in either non-diabetic or diabetic mice. In addition, the number and affinity of histamine H(1) receptors in the frontal cortex were not affected by diabetes. In conclusion, we suggest that the altered neuronal system mediated by the activation of histamine H(1) receptors is involved, at least in part, in the depressive-like behavior seen in diabetic mice.

Synthesis and SAR of N-substituted dibenzazepinone derivatives as novel potent and selective alpha(V)beta(3) antagonists.

Synthesis and SARs of new integrin alpha(V)beta(3) antagonists based on an N-substituted dibenzazepinone scaffold are described. Variation of spacer and guanidine mimetic led to potent compounds exhibiting an IC(50) towards alpha(V)beta(3) in the nanomolar range, high selectivity versus integrin alpha(IIb)beta(3) and efficacy in functional cellular assays.

[A comparative study of the antiarrhythmic action of bonnecor and the mesidide derivatives of alpha-azacycloalkane carboxylic acids]. / Sravnitel'noe izuchenie antiaritmicheskogo deistviia bonnekora i nekotorykh proizvodnykh mezididov al'fa-azatsikloalkankarbonovyykh kislot.

The antiarrhythmic properties of the dibenzazepine derivative bonnecor and derivatives of mesidides of alpha-azacycloalkanocarboxylic acids were studied in various experimental arrhythmia models. The comparative study revealed different antiarrhythmic effects in different arrhythmia models. Bonnecor was found to have a higher antiarrhythmic activity in most arrhythmic models. Tertiary salts were demonstrated to be more potent than quaternary ones.

[The effect of bonnecor on blood coagulability and thrombocyte aggregation in transient myocardial ischemia]. / Vliianie bonnekora na svertyvaemost' krovi i agregatsiiu trombotsitov v usloviiakh tranzitornoi ishemii miokarda.

The experiments on conscious rabbits have indicated that bonnecor given in doses of 0.05 mg/kg and 0.5 mg/kg accelerates clot formation and platelet aggregation, without changing the density of a thrombus. In experimental transient myocardial ischemia, the agent decreases the hypercoagulative change associated with the damaging effect of occlusion and reperfusion.

[Effects of mosapramine (Y-516), a new dopamine D2 antagonist, on reverse tolerance after repeated administration of methamphetamine by means of the ambulation-increasing effect in mice].

Effects of mosapramine (Y-516), a new dopamine D2 antagonist, on reverse tolerance (sensitization) after repeated administration of methamphetamine (MAP; 2 mg/kg, s.c.) were investigated by means of ambulatory activity in mice; and they were compared with those of clocapramine (CCP), bromperidol (BPD) and chlorpromazine (CPZ). Y-516 (0.3, 1, 3 and 10 mg/kg, p.o.), CCP (3, 10 and 30 mg/kg, p.o.), BPD (0.1, 0.3 and 1 mg/kg, p.o.), CPZ (1, 3 and 10 mg/kg, p.o.) or 0.5% methylcellulose (MC; solvent, p.o.) were given to mice 30 min before MAP administration. The ambulatory activity was measured by tilting-type activity changes for 3 hr after MAP. These treatments were repeated 5 times at 3-4 day intervals. Then MAP alone was challenge-administered to all of these mice 3-4 days after the final administration. Marked reverse tolerance was produced after repeated administration of MC plus MAP. On the other hand, the ambulation-increasing effect of MAP was suppressed dose-dependently in groups pretreated with Y-516 or comparison-drugs, although the development of reverse tolerance was not completely inhibited after the repeated administration. In the challenge-administration of MAP, the ambulation-increasing effect was dose-dependently suppressed in the Y-516 group or the comparison-drug plus MAP group as compared with that in the MC plus MAP group.

[The relationship between the chemical structure and anti-arrhythmia action of a number of omega-aminoacyl-3-carbalcoxyaminodibenzazepines]. / Izuchenie zavisimosti mezhdu khimicheskim stroeniem i antiaritmicheskim deistviem v riadu omega-aminoatsil-3-karbalkoksiaminodibenzazepinov.

The antiarrhythmic activity of 20 derivatives of dibenzazepine (the effects on the maximal effective rabbit heart auricle contraction rate, aconitine-induced arrhythmia in rats under or without anesthesia) was studied. It was shown that the most active compounds are those with carbethoxyamine group in position 3 in combination with dimethylamino- or diethylamino-acetyl groups in position 5 of dibenzazepine ring. 5-dimethyl-aminoacetyl-10,11-dihydro-5H-dibenz b, f azepine (GS-015, bonnecor) was selected for the further detailed investigation.

[Pharmacological research on bonnecor and its metabolites]. / Farmakologicheskoe issledovanie bonnekora i ego metabolitov.

The antiarrhythmic and local anesthetic effects of 4 metabolites (G 491, ABD 19-200, ABD 19-199, ABD 19-205) of a new antiarrhythmic drug bonnecor (GS-015) were studied on the models of arrhythmias induced by aconitine (rats), barium chloride (rabbits), electrical fibrillation (cats), ouabain (dogs) as well as surface anesthesia (rabbit cornea). The side effects on the cardiovascular system were investigated on anesthetized cats. As compared with the original compound (bonnecor) metabolites G 491 and ABD 19-200 on different test models exhibited the action which on the antiarrhythmic terms was 2-14 times less weak than that of bonnecor but the metabolites were less toxic. Metabolites ABD 19-199 and ABD 19-205 reach the degree of effectiveness of bonnecor but their toxicity is higher. It follows from the above that the beneficial effect of bonnecor is not achieved by its metabolites.

[A comparative study of the pharmacokinetics and pharmacodynamics of bonnecor]. / Sravnitel'noe izuchenie farmakokinetiki i farmakodinamiki bonnekora.

The pharmacokinetics and pharmacodynamics of bonnecor were studied simultaneously in animals with experimental arrhythmia. It was shown that irrespective of the animal species and individual features of the drug elimination kinetics the level of bonnecor concentration correlated with the antiarrhythmic effect. The data on the excretion of bonnecor and its metabolites in the urine in the dog and man were obtained. The decrease of bioavailability at oral administration of bonnecor was demonstrated to be related to its intensive conversion in metabolite M-I.

Blockade of acquisition of one-way conditioned avoidance responding by haloperidol and metoclopramide but not by thioridazine or clozapine: implications for screening new antipsychotic drugs.

The classical neuroleptic drugs haloperidol and pimozide have a strong disruptive effect on the acquisition of conditioned avoidance responding (CAR), yet have relatively little impact on the performance of previously acquired responses. Separate experiments compared the effects of haloperidol, two atypical neuroleptics, thioridazine and clozapine, and a substituted benzamide, metoclopramide, on one-way avoidance by rats. Thioridazine (10-50 mg/kg) and clozapine (1.25-10.0 mg/kg) disrupted both acquisition and performance of CAR. In contrast, haloperidol (0.075-0.150 mg/kg) and metoclopramide (5.0-7.5 mg/kg) completely blocked the acquisition of CAR, yet initially produced only a slight disruption in the performance of a previously acquired response. The ineffectiveness of the atypical neuroleptics in producing a complete disruption of acquisition of CAR may be due to the anticholinergic properties of these drugs. Alternatively, the differences between metoclopramide and the atypical neuroleptics may be due to a preferential effect of metoclopramide on striatal or amygdaloid dopamine neurotransmission. These results suggest that caution should be exercised in using CAR as an animal model for assessing the antipsychotic potential of new pharmacological agents.

Lack of effects of apomorphine, haloperidol and clozapine on the synthesis and utilization of brain GABA.

The synthesis of GABA was studied as the accumulation of GABA following inhibition of the GABA-alpha-ketoglutaric acid aminotransferase by gamma-acetylenic GABA (GAG) or gamma-vinyl GABA. The disappearance of GABA was studied by means of inhibition of glutamate decarboxylase by 4-deoxypyridoxine. Systemic administration of the dopamine receptor agonist apomorphine did not change the accumulation or the disappearance of GABA in the substantia nigra and the corpus striatum of the rat. However, a very high dose of apomorphine somewhat increased the GAG-induced GABA accumulation in the corpus striatum. The dopamine receptor antagonists haloperidol and clozapine did not modify the accumulation and disappearance of GABA in the two structures, except for a slight decrease in the GAG-induced GABA accumulation in the substantia nigra. Following an acute hemisection, the neural connections between the substantia nigra and the corpus striatum are interrupted on one side of the brain. Apomorphine did not influence the accumulation or the disappearance of GABA in the substantia nigra and in the corpus striatum on the sectioned side of the brain. These results indicate that the synthesis and the utilization of GABA in the two structures studied are not influenced to any greater extent by changes in dopamine receptor activity.

Differential effects of haloperidol, clozapine, and fluperlapine on tuberoinfundibular dopamine neurons and prolactin secretion in the rat.

Two atypical neuroleptic agents, clozapine and fluperlapine, produced rapid elevations in plasma PRL concentrations that were similar in magnitude to those produced by haloperidol. However, the PRL response to clozapine or fluperlapine was of much shorter duration than that elicited by haloperidol. Clozapine, but neither fluperlapine nor haloperidol, produced a rapid increase in the activity of tuberoinfundibular dopamine (TIDA) neurons, as evidenced by an enhanced accumulation of dihydroxyphenylalanine (DOPA) in the median eminence after the inhibition of DOPA decarboxylase. The clozapine-induced increase in DOPA accumulation was evident within 30 minutes after its administration and persisted for at least 4 hours. The clozapine-induced increase in the activity of TIDA neurons may account, in part, for the abbreviated PRL response to this neuroleptic. In addition, ability to produce a short-lived increase in PRL secretion in the rat appears to be common to the atypical neuroleptic drugs.

[Electrophysiologic research on the anti-arrhythmia properties of bonnecor--a new dibenzazepine derivative]. / Elektrofiziologicheskoe issledovanie antiaritmicheskikh svoistv bonnekora--novogo proizvodnogo dibenzazepina.

A new dibenzepin derivative, bonnecor, showed marked antiarrhythmic and antifibrillation properties in anesthetized cats. One and 2 mg/kg doses of the drug reduce cardiac assimilation of imposed ventricular electric stimuli, increase ventricular fibrillation threshold with a strong and lasting effect and prevent arrhythmias and fibrillation due to 10-minute occlusion and subsequent reperfusion of the anterior descending branch of the left coronary artery. Experimental holding of atrial trabecular membrane potential in a frog, in conditions of a double saccharose bridge, showed bonnecor, in 5 X 10(-7) and 1 X 10(-6) g/ml concentrations, to inhibit rapid sodium inflow and slow calcium inflow. It is expected that bonnecor can be used clinically to control critical arrhythmias and prevent sudden cardiac death.

[Anti-arrhythmia and antifibrillatory properties of dibenzazepine derivatives]. / Antiaritmicheskie i antifibrilliatornye svoistva proizvodnykh dibenzazepina.

Antiarrhythmic and antifibrillation properties of bonnecor, a derivative of dibenzepin, were studied in comparison with ethmozine, quinidine and novocainamide, using various experimental arrhythmia models. Bonnecor activity was somewhat smaller than that of ethmozine, and much greater than that of quinidine and novocainamide in the mixed atrioventricular arrhythmia model simulated in aconitin-treated rats and the ventricular arrhythmia model simulated by two-degree coronary occlusion in dogs. Intravenous 1 mg/kg and oral 6 mg/kg bonnecor doses prevented ventricular fibrillation caused by acute coronary occlusion in rats, while ethmozine showed no such effect.