P633H, a novel dual agonist at peroxisome proliferator-activated receptors alpha and gamma, with different anti-diabetic effects in db/db and KK-Ay mice

Current advancement in the preclinical models used for the assessment of diabetic neuropathy

Diabetic neuropathy is one of the prevalent and debilitating microvascular complications of diabetes mellitus, affecting a significant portion of the global population. Relational preclinical animal models are essential to understand its pathophysiology and develop effective treatments. This abstract provides an overview of current knowledge and advancements in such models. Various animal models have been developed to mimic the multifaceted aspects of human diabetic neuropathy, including both type 1 and type 2 diabetes. These models involve rodents (rats and mice) and larger animals like rabbits and dogs. Induction of diabetic neuropathy in these models is achieved through chemical, genetic, or dietary interventions, such as diabetogenic agents, genetic modifications, or high-fat diets. Preclinical animal models have greatly contributed to studying the intricate molecular and cellular mechanisms underlying diabetic neuropathy. They have shed light on hyperglycemia-induced oxidative stress, neuroinflammation, mitochondrial dysfunction, and altered neurotrophic factor signaling. Additionally, these models have allowed for the investigation of morphological changes, functional alterations, and behavioral manifestations associated with diabetic neuropathy. These models have also been crucial for evaluating the efficacy and safety of potential therapeutic interventions. Novel pharmacological agents, gene therapies, stem cell-based approaches, exercise, dietary modifications, and neurostimulation techniques have been tested using these models. However, limitations and challenges remain, including physiological differences between humans and animals, complex neuropathy phenotypes, and the need for translational validation. In conclusion, preclinical animal models have played a vital role in advancing our understanding and management of diabetic neuropathy. They have enhanced our knowledge of disease mechanisms, facilitated the development of novel treatments, and provided a platform for translational research. Ongoing efforts to refine and validate these models are crucial for future treatment developments for this debilitating condition.

New Horizons in Diabetic Neuropathies: An Updated Review on their Pathology, Diagnosis, Mechanism, Screening Techniques, Pharmacological, and Future Approaches

BACKGROUND

One of the largest problems for global public health is diabetes mellitus (DM) and its micro and macrovascular consequences. Although prevention, diagnosis, and treatment have generally improved, its incidence is predicted to keep rising over the coming years. Due to the intricacy of the molecular mechanisms, which include inflammation, oxidative stress, and angiogenesis, among others, discovering treatments to stop or slow the course of diabetic complications is still a current unmet need.

METHODS

The pathogenesis and development of diabetic neuropathies may be explained by a wide variety of molecular pathways, hexosamine pathways, such as MAPK pathway, PARP pathway, oxidative stress pathway polyol (sorbitol) pathway, cyclooxygenase pathway, and lipoxygenase pathway. Although diabetic neuropathies can be treated symptomatically, there are limited options for treating the underlying cause.

RESULT

Various pathways and screening models involved in diabetic neuropathies are discussed, along with their possible outcomes. Moreover, both medicinal and non-medical approaches to therapy are also explored.

CONCLUSION

This study highlights the probable involvement of several processes and pathways in the establishment of diabetic neuropathies and presents in-depth knowledge of new therapeutic approaches intended to stop, delay, or reverse different types of diabetic complications.

Effects of Microalgae on Metabolic Syndrome

Metabolic syndrome (MetS) is a cluster of metabolic disturbances, including abdominal obesity, hypertension, hypertriglyceridemia, reduced high-density lipoprotein cholesterol (HDL-C) and hyperglycemia. Adopting a healthier lifestyle and multiple drug-based therapies are current ways to manage MetS, but they have limited efficacy, albeit the prevalence of MetS is rising. Microalgae is a part of the human diet and has also been consumed as a health supplement to improve insulin sensitivity, inflammation, and several components of MetS. These therapeutic effects of microalgae are attributed to the bioactive compounds present in them that exhibit antioxidant, anti-inflammatory, anti-obesity, antihypertensive, hepatoprotective and immunomodulatory effects. Therefore, studies investigating the potential of microalgae in alleviating MetS are becoming more popular, but a review on this topic remains scarce. In this review, we discuss the effects of microalgae, specifically on MetS, by reviewing the evidence from scientific literature covering in vitro and in vivo studies. In addition, we also discuss the underlying mechanisms that modulate the effects of microalgae on MetS, and the limitations and future perspectives of developing microalgae as a health supplement for MetS. Microalgae supplementation is becoming a viable approach in alleviating metabolic disturbances and as a unique addition to the management of MetS.

Type 2 Diabetes Mellitus: Pathogenic Features and Experimental Models in Rodents

Type 2 diabetes mellitus (T2DM) is the most common endocrine disorder (90%) in the world; it has numerous clinical, immunological, and genetic differences from type 1 diabetes mellitus. The pathogenesis of T2DM is complex and not fully clear. To date, animal models remain the main tool by which to study the pathophysiology and therapy of T2DM. Rodents are considered the best choice among animal models, because they are characterized by a small size, short induction period, easy diabetes induction, and economic efficiency. This review summarizes data on experimental models of T2DM that are currently used, evaluates their advantages and disadvantages vis-a-vis research, and describes in detail the factors that should be taken into account when using these models. Selection of a suitable model for tackling a particular issue is not always trivial; it affects study results and their interpretation.

The Role of Peroxisome Proliferator-Activated Receptor Gamma and Atherosclerosis: Post-translational Modification and Selective Modulators

Atherosclerosis is the hallmark of cardiovascular disease (CVD) which is a leading cause of death in type 2 diabetes patients, and glycemic control is not beneficial in reducing the potential risk of CVD. Clinically, it was shown that Thiazolidinediones (TZDs), a class of peroxisome proliferator-activated receptor gamma (PPARγ) agonists, are insulin sensitizers with reducing risk of CVD, while the potential adverse effects, such as weight gain, fluid retention, bone loss, and cardiovascular risk, restricts its use in diabetic treatment. PPARγ, a ligand-activated nuclear receptor, has shown to play a crucial role in anti-atherosclerosis by promoting cholesterol efflux, repressing monocytes infiltrating into the vascular intima under endothelial layer, their transformation into macrophages, and inhibiting vascular smooth muscle cells proliferation as well as migration. The selective activation of subsets of PPARγ targets, such as through PPARγ post-translational modification, is thought to improve the safety profile of PPARγ agonists. Here, this review focuses on the significance of PPARγ activity regulation (selective activation and post-translational modification) in the occurrence, development and treatment of atherosclerosis, and further clarifies the value of PPARγ as a safe therapeutic target for anti-atherosclerosis especially in diabetic treatment.

Experimental animal models for diabetes and its related complications-a review

Diabetes mellitus, a very common and multifaceted metabolic disorder is considered as one of the fastest growing public health problems in the world. It is characterized by hyperglycemia, a condition with high glucose level in the blood plasma resulting from defects in insulin secretion or its action and in some cases both the impairment in secretion and also action of insulin coexist. Historically, animal models have played a critical role in exploring and describing malady pathophysiology and recognizable proof of targets and surveying new remedial specialists and in vivo medicines. In the present study, we reviewed the experimental models employed for diabetes and for its related complications. This paper reviews briefly the broad chemical induction of alloxan and streptozotocin and its mechanisms associated with type 1 and type 2 diabetes. Also we highlighted the different models in other species and other animals.

Amodiaquine improves insulin resistance and lipid metabolism in diabetic model mice

AIMS

Although peroxisome proliferator-activated receptors (PPARs)α/γ dual agonists can be beneficial for treatment of dyslipidemia in patients with type 2 diabetes, their use is limited owing to various side effects, including body weight gain, edema, and heart failure. We aimed to demonstrate that amodiaquine, an antimalarial agent, has potential as a PPARα/γ dual agonist with low risk of adverse effects.

METHODS

We screened a Prestwick library (Prestwick Chemical; Illkirch, France) to identify novel PPARα/γ dual agonists and selected amodiaquine (4-[(7-chloroquinolin-4-yl)amino]-2-[(diethylamino)methyl]phenol), which activated both PPAR-α & -γ, for further investigation. We performed both in vitro, including glucose uptake assay and fatty acid oxidation assay, and in vivo studies to elucidate the anti-diabetic and anti-obesity effects of amodiaquine.

RESULTS

Amodiaquine selectively activated the transcriptional activities of PPARα/γ and enhanced both fatty acid oxidation and glucose uptake without altering insulin secretion in vitro. In high-fat diet-induced obese and genetically modified obese/diabetic mice, amodiaquine not only remarkably ameliorated insulin resistance, hyperlipidemia, and fatty liver but also decreased body weight gain.

CONCLUSION

Our findings suggest that amodiaquine exerts beneficial effects on glucose and lipid metabolism by concurrent activation of PPARα/γ. Furthermore, amodiaquine acts as an alternative insulin-sensitizing agent with a positive influence on lipid metabolism and has potential to prevent and treat type 2 diabetes while reducing the risk of lipid abnormalities.

A novel PPARα/γ agonist, propane-2-sulfonic acid octadec-9-enyl-amide, ameliorates insulin resistance and gluconeogenesis in vivo and vitro

Peroxisome proliferator-activated receptor alpha/gamma (PPARα/γ) agonists have emerged as important pharmacological agents for improving insulin action. Propane-2-sulfonic acid octadec-9-enyl-amide (N15) is a novel PPARα/γ dual agonist synthesized in our laboratory. The present study investigates the efficacy and safety of N15 on insulin resistance regulation in high fat diet (HFD)-and streptozotocin (STZ)-induced diabetic mice and in palmitic acid (PA)-induced HepG2 cells. Our results showed that N15 remarkably ameliorated insulin resistance and dyslipidemia in vivo, as well as rectified the glucose consumption and gluconeogenesis in vitro. Moreover, the glucose-lowering effect of N15 was associated with PPARγ mediated up-regulation of hepatic glucose consumption and down-regulation of gluconeogenesis. Meanwhile, N15 exerted advantageous effects on glucose and lipid metabolism without triggering weight gain and hepatotoxicity in mice. In conclusion, our data demonstrated that by alleviating glucose and lipid abnormalities, N15 could be used as a potential prophylactic and therapeutic agent against type 2 diabetes and related metabolic disorders.

LH-21, A Peripheral Cannabinoid Receptor 1 Antagonist, Exerts Favorable Metabolic Modulation Including Antihypertensive Effect in KKAy Mice by Regulating Inflammatory Cytokines and Adipokines on Adipose Tissue

Patients with obesity are susceptible to hypertension and diabetes. Over-activation of cannabinoid receptor 1 (CB₁R) in adipose tissue is proposed in the pathophysiology of metabolic disorders, which led to the metabolic dysfunction of adipose tissue and deregulated production and secretion of adipokines. In the current study, we determined the impact of LH-21, a representative peripheral CB₁R antagonist, on the obesity-accompanied hypertension and explored the modulatory action of LH-21 on the adipose tissue in genetically obese and diabetic KKAy mice. 3-week LH-21 treatment significantly decreased blood pressure with a concomitant reduction in body weight, white adipose tissue (WAT) mass, and a slight loss on food intake in KKAy mice. Meanwhile, glucose handling and dyslipidemia were also markedly ameliorated after treatment. Gene expression of pro-inflammatory cytokines in WAT and the aortae were both attenuated apparently by LH-21, as well the mRNA expression of adipokines (lipocalin-2, leptin) in WAT. Concomitant amelioration on the accumulation of lipocalin-2 was observed in both WAT and aortae. In corresponding with this, serum inflammatory related cytokines (tumor necrosis factor α, IL-6, and CXCL1), and lipocalin-2 and leptin were lowered notably. Thus according to current results, it can be concluded that the peripheral CB₁R antagonist LH-21 is effective in managing the obesity-accompanied hypertension in KKAy mice. These metabolic benefits are closely associated with the regulation on the production and secretion of inflammatory cytokines and adipokines in the WAT, particularly alleviated circulating lipocalin-2 and its accumulation in aortae.

Selective Tissue Distribution Mediates Tissue-Dependent PPARγ Activation and Insulin Sensitization by INT131, a Selective PPARγ Modulator

The mechanisms underlying the enhancement of insulin sensitivity by selective peroxisome proliferator-activated receptor γ modulators (sPPARγMs) are still not completely known. Here, the representative sPPARγM, INT131, was used as a probe to investigate the insulin-sensitizing mechanisms of sPPARγM in the context of tissue selective compound distribution and PPARγ regulation. First, 30 mg kg⁻¹ INT131 was observed to produce an insulin-sensitizing effect comparable to that of 10 mg kg⁻¹ rosiglitazone (RSG) in both db/db and DIO mice using the oral glucose and insulin tolerance tests. Similar to RSG, INT131 significantly increased brown adipose tissue (BAT) mass and adipocyte size and up-regulated the expression of BAT-specific genes. Compared with RSG, INT131 exhibited greater potency in inducing white adipose tissue (WAT) browning, decreasing adipocyte size, and increasing BAT-specific and function-related gene expression in subcutaneous WAT (sWAT). However, it did not induce hepatomegaly or hepatic steatosis, which is associated with lower levels of lipogenic genes expression. Pharmacokinetic analysis reveals that in contrast with RSG, INT131 shows higher Cmax, and much longer residency time (AUC_0−12h), as well relatively lower elimination rate in adipose tissues and skeletal muscle, this demonstrated INT131 distributed predominantly in adipose tissue. Whereas, INT131 was less abundant in the liver. These results thus suggest that the tissue-selective distribution underlies INT131's selective PPARγ modulation. Compounds favoring adipose tissue may aid in development of better, safer sPPARγM to address the insulin resistance of diabetes.

Multitargeted bioactive ligands for PPARs discovered in the last decade

Type 2 diabetes took insulin resistance as the main clinical manifestation. PPARs have been reported to be the therapeutic targets of metabolic disorders, such as obesity, hypertension, diabetes, and cardiovascular disease. Previously, PPARγ agonist rosiglitazone was restricted in clinic due to cardiomyocytes infarction, weight gain, and other serious side-effects, which were mainly due to the single and selective PPARγ agonism. In recent years, multitarget-directed PPAR agonists with synergistic reaction as well as fewer side-effect have been the hot topic in designing promising agents. In this review, we updated and generalized the development of PPARγ partial agonists, PPARγ antagonists, PPARα/γ dual agonists, PPARδ partial agonists, PPARδ antagonists, PPARα/δ dual agonists, PPARγ/δ dual agonists, and PPARα/γ/δ pan-agonists published in recent decade. Most of these molecules were modified from known structures or came from high-throughput screening. Among these molecules, some were expected to be promising drugs against metabolic disorders, while others seemed to provide new insight for designing novel PPAR agents.

A metabolomic study of the PPARδ agonist GW501516 for enhancing running endurance in Kunming mice

Exercise can increase peroxisome proliferator-activated receptor-δ (PPARδ) expression in skeletal muscle. PPARδ regulates muscle metabolism and reprograms muscle fibre types to enhance running endurance. This study utilized metabolomic profiling to examine the effects of GW501516, a PPARδ agonist, on running endurance in mice. While training alone increased the exhaustive running performance, GW501516 treatment enhanced running endurance and the proportion of succinate dehydrogenase (SDH)-positive muscle fibres in both trained and untrained mice. Furthermore, increased levels of intermediate metabolites and key enzymes in fatty acid oxidation pathways were observed following training and/or treatment. Training alone increased serum inositol, glucogenic amino acids, and branch chain amino acids. However, GW501516 increased serum galactose and β-hydroxybutyrate, independent of training. Additionally, GW501516 alone raised serum unsaturated fatty acid levels, especially polyunsaturated fatty acids, but levels increased even more when combined with training. These findings suggest that mechanisms behind enhanced running capacity are not identical for GW501516 and training. Training increases energy availability by promoting catabolism of proteins, and gluconeogenesis, whereas GW501516 enhances specific consumption of fatty acids and reducing glucose utilization.

Novel PPAR pan agonist, ZBH ameliorates hyperlipidemia and insulin resistance in high fat diet induced hyperlipidemic hamster

Effective and safe pharmacological interventions for hyperlipidemia remains badly needed. By incorporating the key pharmacophore of fibrates into the natural scaffold of resveratrol, a novel structural compound ZBH was constructed. In present study, we found ZBH reserved approximately one third of the sirtuin 1 (SIRT1) activation produced by resveratrol at in-vitro enzyme activity assay, directly bound to and activated all three peroxisome proliferator-activated receptor (PPAR) subtypes respectively in PPAR binding and transactivation assays. Moreover, ZBH (EC_50, 1.75 µM) activate PPARα 21 fold more efficiently than the well-known PPAR pan agonist bezafibrate (EC₅₀, 37.37 µM) in the cellular transactivation assays. In the high fat diet induced hyperlipidemic hamsters, 5-week treatment with ZBH significantly lowered serum triglyceride, total cholesterol, LDL-C, FFA, hyperinsulinemia, and improved insulin sensitivity more potently than bezafibrate. Meanwhile, serum transaminases, creatine phosphokinase and CREA levels were found not altered by ZBH intervention. Mechanism study indicated ZBH promoted the expression of PPARα target genes and SIRT1 mRNA. Hepatic lipogenesis was markedly decreased via down-regulation of lipogenic genes, and fatty acid uptake and oxidation was simultaneously increased in the liver and skeletal muscle via up-regulation of lipolysis genes. Glucose uptake and utilization was also significantly promoted in skeletal muscle. These results suggested that ZBH significantly lowered hyperlipidemia and ameliorated insulin resistance more efficiently than bezafibrate in the hyperlipidemic hamsters primarily by activating of PPARα, and SIRT1 promotion and activation. ZBH thus presents a potential new agent to combat hyperlipidemia.

Potent anti-diabetic effects of MHY908, a newly synthesized PPAR α/γ dual agonist in db/db mice

Peroxisome proliferator-activated receptor (PPAR) α/γ dual agonists have been developed to alleviate metabolic disorders and have the potential to be used as therapeutic agents for the treatment of type 2 diabetes. In this study, we investigated the effects of a newly synthesized PPAR α/γ dual agonist, 2-[4-(5-chlorobenzo [d] thiazol-2-yl) phenoxy]-2-methylpropanoic acid (MHY908) on type 2 diabetes in vitro and in vivo. To obtain initial evidence that MHY908 acts as a PPAR α/γ dual agonist, ChIP and reporter gene assays were conducted in AC2F rat liver cells, and to investigate the anti-diabetic effects and molecular mechanisms, eight-week-old, male db/db mice were allowed to eat ad libitum, placed on calorie restriction, or administered MHY908 (1 mg or 3 mg/kg/day) mixed in food for 4 weeks. Age-matched male db/m lean mice served as non-diabetic controls. It was found that MHY908 enhanced the binding and transcriptional activity of PPAR α and γ in AC2F cells, and it reduced serum glucose, triglyceride, and insulin levels, however increased adiponectin levels without body weight gain. In addition, MHY908 significantly improved hepatic steatosis by enhancing CPT-1 levels. Remarkably, MHY908 reduced endoplasmic reticulum (ER) stress and c-Jun N-terminal kinase (JNK) activation in the livers of db/db mice, and subsequently reduced insulin resistance. The study shows MHY908 has beneficial effects on type 2 diabetes by simultaneously activating PPAR α/γ and improving ER stress, and suggests that MHY908 could have a potent anti-diabetic effect as a PPAR α/γ dual agonist, and potential for the treatment of type 2 diabetes.

Histopathological Evaluation of Heart Toxicity of a Novel Selective PPAR-γ Agonists CKD-501 in db/db Mice

High risk of cardiovascular diseases caused by existing PPAR-γ agonists such as rosiglitazone and pioglitazone has been recently reported. CKD-501 is a novel selective PPAR-γ agonist as a potential target to reduce cardiovascular risk in non-insulin dependent diabetes mellitus (NIDDM). In this study, We investigated potential cardiotoxicity of CKD-501 and compared its toxicity with that of rosiglitazone or pioglitazone using db/db mice. After 12-week repeated administration of CKD-501 at doses of 3, 10 and 30 mg/kg/day or rosiglitazone at doses of 10 and 30 mg/kg/day or pioglitazone at doses of 200 and 540 mg/kg/day, animals were sacrificed for investigation of potential toxicities. Diameters of left ventricles and areas of cardiomyocytes were measured. And lipid accumulation and apoptosis in heart muscle were examined by oil red O staining and TUNEL staining, respectively. Diameters of left ventricles were significantly increased in high dose treatment group of pioglitazone compared to control (p<0.05), while other groups showed a tendency for an increase. All test articles induced significantly the increase of area of cardiomyocytes in heart compared to control (p<0.01), in regular order as pioglitazone > CKD-501 ≥ rosiglitazone. However, lipid accumulation and apoptotic changes in heart were not observed in all dosing groups. Taken together, the myocardial cell hypertrophy of CKD-501 are relatively lower than that of pioglitazone and similar to rosiglitazone. And it is suggested that the myocardial cell hypertrophy of CKD-501 are less adverse in clinical use for the management of the NIDDM.

The use of animal models in diabetes research

Diabetes is a disease characterized by a relative or absolute lack of insulin, leading to hyperglycaemia. There are two main types of diabetes: type 1 diabetes and type 2 diabetes. Type 1 diabetes is due to an autoimmune destruction of the insulin-producing pancreatic beta cells, and type 2 diabetes is caused by insulin resistance coupled by a failure of the beta cell to compensate. Animal models for type 1 diabetes range from animals with spontaneously developing autoimmune diabetes to chemical ablation of the pancreatic beta cells. Type 2 diabetes is modelled in both obese and non-obese animal models with varying degrees of insulin resistance and beta cell failure. This review outlines some of the models currently used in diabetes research. In addition, the use of transgenic and knock-out mouse models is discussed. Ideally, more than one animal model should be used to represent the diversity seen in human diabetic patients.

Bilobetin ameliorates insulin resistance by PKA-mediated phosphorylation of PPARα in rats fed a high-fat diet

BACKGROUND AND PURPOSE

The amelioration of insulin resistance by bilobetin is closely related to its hypolipidaemic effect. The aim of the present study was to determine the insulin-sensitizing mechanism of bilobetin by elucidating its effect on lipid metabolism.

EXPERIMENTAL APPROACH

Rats fed a high-fat diet were treated with bilobetin for either 4 or 14 days before applying a hyperinsulinaemic-euglycaemic clamp. Triglyceride and fatty acids labelled with radioactive isotopes were used to track the transportation and the fate of lipids in tissues. The activity of lipid metabolism-related enzymes and β-oxidation rate were measured. Western blot was used to investigate the phosphorylation, translocation and expression of PPARα in several tissues and cultured cells. The location of amino acid residues subjected to phosphorylation in PPARα was also studied.

KEY RESULTS

Bilobetin ameliorated insulin resistance, increased the hepatic uptake and oxidation of lipids, reduced very-low-density lipoprotein triglyceride secretion and blood triglyceride levels, enhanced the expression and activity of enzymes involved in β-oxidation and attenuated the accumulation of triglycerides and their metabolites in tissues. Bilobetin also increased the phosphorylation, nuclear translocation and activity of PPARα accompanied by elevated cAMP level and PKA activity. Threonine-129-alanine and/or serine-163-alanine mutations on the PPARα genes and PKA inhibitors prevented the effects of bilobetin on PPARα. However, cells overexpressing PKA appeared to stimulate the phosphorylation, nuclear translocation and activity of PPARα.

CONCLUSIONS AND IMPLICATIONS

Bilobetin treatment ameliorates hyperlipidaemia, lipotoxicity and insulin resistance in rats by stimulating PPARα-mediated lipid catabolism. PKA activation is crucial for this process.

Novel selective cannabinoid CB(1) receptor antagonist MJ08 with potent in vivo bioactivity and inverse agonistic effects

AIM

To characterize the biological profiles of MJ08, a novel selective CB(1) receptor antagonist.

METHODS

Radioligand binding assays were performed using rat brain and spleen membrane preparations. CB(1) and CB(2) receptor redistribution and intracellular Ca(2+) ([Ca(2+)](i)) assays were performed with IN CELL Analyzer. Inverse agonism was studied using intracellular cAMP assays, and in guinea-pig ileum and mouse vas deferens smooth muscle preparations. In vivo pharmacologic profile was assessed in diet-induced obesity (DIO) mice.

RESULTS

In radioligand binding assay, MJ08 selectively antagonized CB(1) receptor (IC(50)=99.9 nmol/L). In EGFP-CB(1)_U2OS cells, its IC(50) value against CB(1) receptor activation was 30.23 nmol/L (SR141716A: 32.16 nmol/L). WIN 55,212-2 (1 μmol/L) increased [Ca(2+)](i) in the primary cultured hippocampal neuronal cells and decreased cAMP accumulation in CHO-hCB(1) cells. MJ08 (10 nmol/L-10 μmol/L) blocked both the WIN 55,212-2-induced effects. Furthermore, MJ08 reversed the inhibition of electrically evoked twitches of mouse vas deferens by WIN 55,212-2 (pA(2)=10.29±1.05). MJ08 and SR141716A both showed an inverse agonism activity by markedly promoting the contraction force and frequency of guinea pig ileum muscle. MJ08 significantly increased the cAMP level in CHO-hCB(1) cells with an EC(50) value of 78.6 nmol/L, which was lower than the EC(50) value for SR141716A (159.2 nmol/L). Besides the more potent pharmacological effects of cannabinoid CB(1) receptor antagonism in DIO mice, such as reducing food intake, decreasing body weight, and ameliorating dyslipidemia, MJ08 (10 mg/kg) unexpectedly raised the fasted blood glucose in vivo.

CONCLUSION

MJ08 is a novel, potent and selective CB(1) receptor antagonist/inverse agonist with potent bioactive responses in vitro and in vivo that may be useful for disclosure the versatile nature of CB(1) receptors.