Bo-Hua Zhong

Antidepressant-like effects of 071031B, a novel serotonin and norepinephrine reuptake inhibitor

SNRIs (serotonin and norepinephrine reuptake inhibitors) have been proposed to exert increased therapeutic efficacy or be faster acting compared to commonly used antidepressants. In this study, we performed in vitro binding and uptake assays and in vivo behavioral tests to assess the pharmacological properties and antidepressant-like efficacy of the compound 071031B; we also performed cytotoxicity tests using HepG2 cells and SH-SY5Y cells to predict the toxicity of 071031B. In vitro, 071031B had high affinity for both serotonin transporters and norepinephrine transporters prepared from rat cortex tissue (Ki=2.68 and 1.09 nM, respectively) and recombinant cells (Ki=1.57 and 0.36 nM, respectively). Moreover, 071031B also potently inhibited the uptake of serotonin (5-HT) and norepinephrine (NE) into rat cortical synaptosomes (Ki=1.99 and 1.09 nM, respectively) and recombinant cells (Ki=3.23 and 0.79 nM, respectively). In vivo, acute administration of 071031B dose-dependently reduced the immobility time in the tail suspension test in mice and the forced swimming test in mice and rats with higher efficacy than duloxetine and showed no stimulatory effect on the locomotor activity. Chronic 071031B treatment (5 or 10mg/kg) significantly reversed depressive-like behaviors in chronically stressed rats, including reduced sucrose preference, decreased locomotor activity, and prolonged latency to begin eating. Furthermore, 071031B also exhibited lower cytotoxicity in HepG2 cells and SH-SY5Y cells in vitro than duloxetine. These findings suggest that 071031B is a novel, balanced serotonin and norepinephrine reuptake inhibitor, with more potent antidepressant effects and lower hepatotoxicity and neurotoxicity in vitro than duloxetine.

The discovery of 071031B, a novel serotonin and noradrenaline reuptake inhibitor

Depression is a severe mood disorder with increasing morbidity and suicidality, while the current therapy is not satisfactory. Serotonin and noradrenaline reuptake inhibitors (SNRIs) have been reported to have higher efficacy and/or faster acting rate than commonly used antidepressants. The present study was designed to screen the potential SNRIs, using in vitro radioligand receptor binding assays and in vivo animal tests, and introduced the discovery of 071031B. In the tail suspension test and forced swimming test in mice, six compounds (071017S, 071026W, 071031A, 071031B, 080307A and 080307B) showed robust antidepressant activity, without stimulant effect on the locomotor activity or other side effects, and the minimal effective dose of 071017S, 071026W, 071031A and 071031B was less than that of duloxetine; in vitro binding tests indicated that 071031B had high affinity to both serotonin transporter and noradrenaline transporter with similar inhibitory rates to duloxetine at 1 and 100 nM; acute toxicity test indicated that the LD50 value of 071031B was similar to that of duloxetine. These findings demonstrated that this integrated system, combining high throughput screening technology and in vivo animal tests, is effective to screen potential monoamine reuptake inhibitors fast and accurately; 071031B is expected to be a novel serotonin and noradrenaline reuptake inhibitor for its robust antidepressant activity and transporter affinity.

Effects of 071031B, a novel serotonin and norepinephrine reuptake inhibitor, on monoamine system in mice and rats.

Our previous study indicated that 071031B, a novel potential serotonin and norepinephrine reuptake inhibitor, showed robust antidepressant activity in multiple depression models, and could simultaneously inhibit 5-HT and NE reuptake in vitro. The present study was to evaluate the effects of 071031B on monoamine system in vivo, by using pharmacological models, including 5-HTP induced head-twitch test, yohimbine toxicity potentiation test, and reserpine induced hypothermia test, and determining monoamine transmitter levels in reserpine induced monoamine depletion model or chronic unpredictable stress (CUS) model. Results in pharmacological models indicated that acute administration of 071031B at 5-20 mg/kg significantly enhanced 5-HTP induced head-twitch behavior, potentiated yohimbine induced lethal rate, and reversed reserpine induced hypothermia. Further monoamine assays demonstrated that acute or chronic administration of 071031B at 10 or 20 mg/kg increased 5-HT and/or NE levels in various brain regions in reserpine or CUS induced monoamine depletion models, respectively, without effect on DA and its metabolites. Our results revealed that 071031B produces potent inhibition of 5-HT and NE reuptake in vivo.

Evaluation of the analgesic effects of ammoxetine, a novel potent serotonin and norepinephrine reuptake inhibitor

Aim:The selective serotonin (5-HT) and norepinephrine (NE) reuptake inhibitors (SNRIs) are commonly used for the treatment of neuropathic pain and fibromyalgia. Ammoxetine ((±)-3-(benzo[d] [1,3]dioxol-4-yloxy)-N-methyl-3-(thiophen-2-yl)propan-1-amine) has been identified as a novel potent SNRI. In this study, we evaluated the acute analgesic properties of ammoxetine in different animal models of pain, and examined the involvement of monoamines in its analgesic actions.Methods:The analgesic effects of ammoxetine were assayed using models of acetic acid- and formalin-induced pain in mice, neuropathic pain induced by sciatic nerve injury (SNI), chronic constriction injury (CCI) and reserpine-induced fibromyalgia pain in rats. The contents of 5-HT and NE in brain regions of fibromyalgia rats were measured using HPLC-ECD. In all the experiments, duloxetine was used as a positive control drug.Results:Oral administration of ammoxetine (0.625–10 mg/kg) or duloxetine (2.5–40 mg/kg) dose-dependently decreased the number of acetic acid-induced writhing and formalin-induced first phase and second phase paw licking time in mice. Oral administration of ammoxetine (2.5–10 mg/kg) or duloxetine (10 mg/kg) alleviated mechanical allodynia in SNI and CCI rats and thermal hyperalgesia in CCI rats. The antiallodynic effect of ammoxetine in CCI rats was abolished by pretreatment with para-chlorophenylalanine methyl ester hydrochloride (PCPA, a 5-HT synthesis inhibitor) or α-methyl-para-tyrosine methylester (AMPT, a catecholamine synthesis inhibitor). Oral administration of ammoxetine (30 mg/kg) or duloxetine (50 mg/kg) significantly attenuated tactile allodynia in rats with reserpine-induced fibromyalgia. In the fibromyalgia rats, administration of ammoxetine (10, 30 mg/kg) or duloxetine (30, 50 mg/kg) dose-dependently increased the levels of 5-HT and NE, and decreased the metabolite ratio of 5-HT (5-HIAA/5-HT) in the spinal cord, hypothalamus, thalamus and prefrontal cortex.Conclusion:Ammoxetine effectively alleviates inflammatory, continuous, neuropathic and fibromyalgia-related pain in animal models, which can be attributed to enhanced neurotransmission of 5-HT and NE in the descending inhibitory systems.

Ammoxetine attenuates diabetic neuropathic pain through inhibiting microglial activation and neuroinflammation in the spinal cord

BackgroundDiabetic neuropathic pain (DNP) is a common and distressing complication in patients with diabetes, and the underlying mechanism remains unclear. Tricyclic antidepressants (TCAs) and serotonin and norepinephrine reuptake inhibitors (SNRIs) are recommended as first-line drugs for DNP. Ammoxetine is a novel and potent SNRI that exhibited a strong analgesic effect on models of neuropathic pain, fibromyalgia-related pain, and inflammatory pain in our primary study. The present study was undertaken to investigate the chronic treatment properties of ammoxetine on DNP and the underlying mechanisms for its effects.MethodsThe rat model of DNP was established by a single streptozocin (STZ) injection (60xa0mg/kg). Two weeks after STZ injection, the DNP rats were treated with ammoxetine (2.5, 5, and 10xa0mg/kg/day) for 4xa0weeks. The mechanical allodynia and locomotor activity were assayed to evaluate the therapeutic effect of ammoxetine. In mechanism study, the activation of microglia, astrocytes, the protein levels of pro-inflammatory cytokines, the mitogen-activated protein kinases (MAPK), and NF-κB were evaluated. Also, microglia culture was used to assess the direct effects of ammoxetine on microglial activation and the signal transduction mechanism.ResultsTreatment with ammoxetine for 4xa0weeks significantly relieved the mechanical allodynia and ameliorated depressive-like behavior in DNP rats. In addition, DNP rats displayed increased activation of microglia in the spinal cord, but not astrocytes. Ammoxetine reduced the microglial activation, accumulation of pro-inflammatory cytokines, and activation of p38 and c-Jun N-terminal kinase (JNK) in the spinal cord of DNP rats. Furthermore, ammoxetine displayed anti-inflammatory effects upon challenge with LPS in BV-2 microglia cells.ConclusionOur results suggest that ammoxetine may be an effective treatment for relieving DNP symptoms. Moreover, a reduction in microglial activation and pro-inflammatory release by inhibiting the p-p38 and p-JNK pathways is involved in the mechanism.

Pharmacokinetic profiles contribute to the differences in behavioral pharmacology of 071031B enantiomers as novel serotonin and norepinephrine reuptake inhibitors

Our previous study indicated that a chiral compound 071031B was a novel serotonin and noradrenaline reuptake inhibitor with superior antidepressant activity compared to duloxetine. The present study aimed to investigate chiral pharmacology differences of 071031B enantiomers, S-071031B and R-071031B, and disclose mechanisms underlying the behavioral differences based on target profiles and pharmacokinetic profiles. In vivo behavioral tests indicated that S-071031B was more potent than R-071031B in two depression models (the forced swimming test in mice and rats) and two pain models (the acetic acid-induced writhing and formalin tests in mice). In vitro assays revealed that both S-071031B and R-071031B showed high affinity for human serotonin transporters and norepinephrine transporters with equal potency, and showed consistently equipotent inhibitory effects on serotonin and norepinephrine uptake. Pharmacokinetic studies demonstrated that oral availability and hepatic metabolism, rather than pH stability, intestinal transport, and plasma binding, contributed to enantiomers’ behavioral differences. Based on these findings, it is suggested that S-071031B is a more active enantiomer, and the differential pharmacokinetic profiles, but not target affinity, contribute to differences of S-071031B and R-071031B in behavioral pharmacology. Moreover, current PK-PD study may provide positive exploration for chiral antidepressants development.

Antidepressant-like Effects of ZBH2012001, a Novel Potent Serotonin and Norepinephrine Reuptake Inhibitor

The present study was conducted to evaluate the antidepressant‐like effects of ZBH2012001, a novel potential serotonin and norepinephrine reuptake inhibitor (SNRI).