Antidepressant Effects of Ketamine on Depression-like Behavior in Juvenile Mice after Neonatal Dexamethasone Exposure

Depressive-like behavior and cognitive impairment induced by acute administration of dexamethasone: Pharmacological effects of 2-phenyl-3-(phenylselanyl)benzofuran in female Swiss mice

Synthetic glucocorticoid administration has been reported to play a role in depression and cognitive decline. The present study investigated the 2-phenyl-3-(phenylselanyl)benzofuran (SeBZF1) effects against the depressive-like behavior, memory impairment, and neurochemical alterations caused by acute dexamethasone administration in female Swiss mice. A dexamethasone dose-response curve (0.07-0.5 mg/kg, subcutaneous route, s.c.) was initially performed to validate the depressive-like behavior induction, in which the 0.25 mg/kg dose was more effective. Two experimental sets were performed to test the SeBZF1 (5 and 50 mg/kg, intragastric route, i.g.) pharmacological effect in this animal model. The 1st set revealed that the SeBZF1 reverses the dexamethasone-induced depressive-like behavior in the tail suspension test and in the splash test. In the 2nd experimental set, the compound effects of reversing the depressive-like behavior in the forced swimming test and the memory deficit in the Y-maze test induced by acute treatment with dexamethasone were demonstrated. Furthermore, SeBZF1 reversed the increase in the monoamine oxidase (MAO) activity in the prefrontal cortex (isoforms A and B) and in the hypothalamus (isoform A) caused by dexamethasone. However, no changes were observed in hippocampal MAO activity. Furthermore, animals treated with dexamethasone and SeBZF1 demonstrated a partially lower acetylcholinesterase activity in the prefrontal cortex compared with the induced group. In summary, the present study demonstrated that SeBZF1 reverses depressive-like behavior and memory deficits caused by acute dexamethasone treatment in female Swiss mice. Possibly the compound exerts its antidepressant-like action by increasing the availability of monoamines, while its effects on memory are still partially understood.

Neurobiological, behavioral, and cognitive effects of ketamine in adolescents: A review of human and pre-clinical research

S-ketamine is approved for treatment-resistant patients with depression and adult patients with suicide behavior. While ketamine is therapeutically beneficial in adults, there is a dearth of research on the effects of ketamine on adolescent brain function and behavior. In this review we summarize the current literature on the neurobiological and behavioral effects of adolescent ketamine exposure in preclinical animal models and humans. A search of PubMed was conducted using pre-defined criteria, resulting in the evaluation of 406 articles. A total of 39 animal studies and 7 human studies met the selection criteria. The included studies examined the effects of ketamine exposure during adolescence and excluded studies on ketamine use for pain or anesthesia and ketamine as a model of schizophrenia. Pre-clinical animal models of adolescent ketamine exposure show ketamine-induced neurotoxicity and apoptosis, and changes in locomotor activity, social behaviors, anxiety- and depression-like behaviors, and memory. There is variability in the results, and differences in ketamine dose and length of exposure appears to influence the results. Ketamine reduces symptoms of depression and anxiety and improves mood in human adolescents. Much of the literature on adolescent ketamine exposure examines the effects in males, with more limited research in females. Relatively little research has focused on adolescent ketamine exposure. Despite its effectiveness for mitigating symptoms of depression, adolescent ketamine exposure can disrupt memory and other behaviors and have deleterious effects on brain function. Further research is warranted to better define doses and dosing paradigms that are beneficial without unintended side effects in adolescence.

The effect of deer antler from East Kalimantan to increase trabecular bone density and calcium levels in serum on osteoporotic mice

OBJECTIVES

Glucocorticoid-induced osteoporosis (dexamethasone) is a primary cause of secondary osteoporosis by the decreasing formation and increasing resorption activities. Previously, the in vitro study showed that 70% ethanol and aqueous extract of deer antler have increased alkaline phosphatase in osteoblast cell that known as marker of bone formation. The mind of this study is to analyze the effect of deer antlers in increasing the bone trabecular density of osteoporosis-induced male mice.

METHODS

This study used a post-test control group design. A total of 54 healthy male mice were randomly divided to nine groups, i.e., healthy control, osteoporotic, positive control, 70% ethanol (4, 8, and 12 mg/kg BW), and aqueous extracts (4, 8, and 12 mg/kg BW) of deer antler groups. All of the interventions were given 1 mL of test sample for 4 weeks orally. The bone densities were determined using histomorphometry by Image J and Adobe Photoshop. The statistical data were performed using SPSS 23 and statistical significance was set at p<0.05.

RESULTS

The results showed that alendronate group, 70% ethanol, and aqueous extract groups increased bone density and calcium levels in serum (p<0.05) compared to osteoporotic group in dose dependent manner. It indicated that 70% ethanol and aqueous extract of deer antler stimulating bone turnover and aqueous extract showed the highest.

CONCLUSIONS

Dexamethasone induction for 4 weeks caused osteoporotic mice and the administration of 70% ethanol and aqueous extracts of deer antler from East Kalimantan increased trabecular bone density and calcium levels in dose dependent manner.

AMPA receptor-mTORC1 signaling activation is required for neuroplastic effects of LY341495 in rat hippocampal neurons

The group II metabotropic glutamate 2/3 (mGlu_2/3) receptor antagonist LY341495 produces antidepressant-like effects by acting on mammalian target of rapamycin complex 1 (mTORC1) signaling and α-amino-3-hydroxy-5-methylisoxazole-4-propionate (AMPA) receptors in rodent. We investigated whether LY341495 affects neuroplasticity via these mechanisms in rat primary hippocampal cultures under conditions of dexamethasone (DEX)-induced neurotoxicity. Ketamine was used for comparison. Hippocampal cultures were treated with LY341495 under conditions of DEX-induced toxicity. Changes in mTORC1-mediated proteins were determined by Western blotting analyses. Changes in dendritic outgrowth and spine density were evaluated via immunostaining. LY341495 significantly prevented DEX-induced decreases in the levels of mTORC1, 4E-BP1, and p70S6K phosphorylation as well as the levels of the synaptic proteins. These effects were blocked by pretreatment with the AMPA receptor inhibitor 2,3-dihydroxy-6-nitro-7sulfamoyl-benzo(f)quinoxaline (NBQX) and the mTORC1 inhibitor rapamycin. LY341495 significantly attenuated DEX-induced decreases in dendritic outgrowth and spine density. Pretreatment with rapamycin and NBQX blocked these effects of LY341495. Further analyses indicted that induction of BDNF expression produced by LY341495 was blocked by pretreatment with NBQX and rapamycin. LY341495 has neuroplastic effects by acting on AMPA receptor-mTORC1 signaling under neurotoxic conditions. Therefore, activation of AMPA receptor and mTORC1 signaling, which enhance neuroplasticity, may be novel targets for new antidepressants.

Rapid-acting antidepressant ketamine, its metabolites and other candidates: A historical overview and future perspective

Major depressive disorder (MDD) is one of the most disabling psychiatric disorders. Approximately one-third of the patients with MDD are treatment resistant to the current antidepressants. There is also a significant therapeutic time lag of weeks to months. Furthermore, depression in patients with bipolar disorder (BD) is typically poorly responsive to antidepressants. Therefore, there exists an unmet medical need for rapidly acting antidepressants with beneficial effects in treatment-resistant patients with MDD or BD. Accumulating evidence suggests that the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine produces rapid and sustained antidepressant effects in treatment-resistant patients with MDD or BD. Ketamine is a racemic mixture comprising equal parts of (R)-ketamine (or arketamine) and (S)-ketamine (or esketamine). Because (S)-ketamine has higher affinity for NMDAR than (R)-ketamine, esketamine was developed as an antidepressant. On 5 March 2019, esketamine nasal spray was approved by the US Food and Drug Administration. However, preclinical data suggest that (R)-ketamine exerts greater potency and longer-lasting antidepressant effects than (S)-ketamine in animal models of depression and that (R)-ketamine has less detrimental side-effects than (R,S)-ketamine or (S)-ketamine. In this article, the author reviews the historical overview of the antidepressant actions of enantiomers of ketamine and its major metabolites norketamine and hydroxynorketamine. Furthermore, the author discusses the other potential rapid-acting antidepressant candidates (i.e., NMDAR antagonists and modulators, low-voltage-sensitive T-type calcium channel inhibitor, potassium channel Kir4.1 inhibitor, negative modulators of γ-aminobutyric acid, and type A [GABA_A ] receptors) to compare them with ketamine. Moreover, the molecular and cellular mechanisms of ketamine's antidepressant effects are discussed.

Effect of neonatal dexamethasone treatment on cognitive abilities of adult male mice and gene expression in the hypothalamus

The early postnatal period is critical for the development of the nervous system. Stress during this period causes negative long-term effects, which are manifested at both behavioral and molecular levels. To simulate the elevated glucocorticoid levels characteristic of early-life stress, in our study we used the administration of dexamethasone, an agonist of glucocorticoid receptors, at decreasing doses at the first three days of life (0.5, 0.3, 0.1 mg/kg, s.c.). In adult male mice with neonatal dexamethasone treatment, an increase in the relative weight of the adrenal glands and a decrease in body weight were observed, while the basal level of corticosterone remained unchanged. Dexamethasone treatment in early life had a negative impact on the learning and spatial memory of adult mice in the Morris water maze. We analyzed the effect of elevated glucocorticoid levels in early life on the expression of the Crh, Avp, Gr, and Mr genes involved in the regulation of the HPA axis in the hypothalami of adult mice. The expression level of the mineralocorticoid receptor gene (Mr) was significantly downregulated, and the glucocorticoid receptor gene (Gr) showed a tendency towards decreased expression (p = 0.058) in male mice neonatally treated with dexamethasone, as compared with saline administration. The expression level of the Crh gene encoding corticotropin-releasing hormone was unchanged, while the expression of the vasopressin gene (Avp) was increased in response to neonatal administration of dexamethasone. The obtained results demonstrate a disruption of negative feedback regulation of the HPA axis, which involves glucocorticoid and mineralocorticoid receptors, at the level of the hypothalamus. Malfunction of the HPA axis as a result of activation of the glucocorticoid system in early life may cause the development of cognitive impairment in the adult mice.

 

TDAG51 is a crucial regulator of maternal care and depressive-like behavior after parturition

Postpartum depression is a severe emotional and mental disorder that involves maternal care defects and psychiatric illness. Postpartum depression is closely associated with a combination of physical changes and physiological stress during pregnancy or after parturition in stress-sensitive women. Although postpartum depression is relatively well known to have deleterious effects on the developing fetus, the influence of genetic risk factors on the development of postpartum depression remains unclear. In this study, we discovered a novel function of T cell death-associated gene 51 (TDAG51/PHLDA1) in the regulation of maternal and depressive-like behavior. After parturition, TDAG51-deficient dams showed impaired maternal behavior in pup retrieving, nursing and nest building tests. In contrast to the normal dams, the TDAG51-deficient dams also exhibited more sensitive depressive-like behaviors after parturition. Furthermore, changes in the expression levels of various maternal and depressive-like behavior-associated genes regulating neuroendocrine factor and monoamine neurotransmitter levels were observed in TDAG51-deficient postpartum brain tissues. These findings indicate that TDAG51 plays a protective role against maternal care defects and depressive-like behavior after parturition. Thus, TDAG51 is a maternal care-associated gene that functions as a crucial regulator of maternal and depressive-like behavior after parturition.

Postpartum depression is a severe emotional and mental disease that can affect women typically after parturition. However, the genetic risk factors associated with the development of postpartum depression are still largely unknown. We discovered a novel function of T cell death-associated gene 51 (TDAG51) in the regulation of maternal behavior and postpartum depression. We report that TDAG51 deficiency induces depressive-like and abnormal maternal behavior after parturition. The loss of TDAG51 in postpartum brain tissues induces changes in the expression levels of various maternal and depressive-like behavior-associated genes that regulate the levels of neuroendocrine factors and monoamine neurotransmitters. TDAG51 is a maternal care-associated gene that functions as a crucial regulator of maternal and depressive-like behavior after parturition.

Peritoneal endometriosis induces time-related depressive- and anxiety-like alterations in female rats: involvement of hippocampal pro-oxidative and BDNF alterations

Endometriosis is a gynecological condition affecting 10% of women in reproductive age. High rates of depression and anxiety are observed in these patients. The mechanisms underlying endometriosis-induced behavioral alterations are still elusive. Animal models provide a useful tool to study the temporal sequence and biological pathways involved in this disease and comorbid states. Here, we sought to characterize time-related behavioral alterations in rats submitted to endometriosis model (EM) induced by peritoneal auto-transplantation of uterine tissues weekly for three weeks. Corticosterone stress reactivity, oxidative stress markers - reduced glutathione (GSH), lipid peroxidation, activity of superoxide dismutase (SOD) and myeloperoxidase (MPO) - and brain-derived-neurotrophic factor (BDNF) levels in the hippocampus were also evaluated. We observed a progressive increase in anxiety-like behavior from 14th to 21st days post-EM. Despair-like behavior was observed from the 14th day post-EM on, while anhedonia and apathetic-like behaviors accompanied by increased corticosterone stress response were detected on 21 days post-EM. Increased pain sensitivity was observed from the 7th day post-EM and was accompanied by increased endometrioma weight. The pro-oxidative alterations, decreased GSH and increased SOD activity were observed on 21 days post-EM, except for lipid peroxidation that was altered from the 14th day. Decreased BDNF also occurred on the 21st day. Therefore, this study demonstrates that EM is related to several features of clinical depression and proposes the contribution of hippocampal oxidative state and neurotrophic support for the emergence of these changes. Our results support the use of this model as a useful tool to test new strategies for endometriosis-related neuropsychiatric symptoms.

Abnormalities in Inflammatory Cytokines Confer Susceptible to Chronic Neuropathic Pain-related Anhedonia in a Rat Model of Spared Nerve Injury

Objective

Patients with chronic neuropathic pain (CNP) have a higher incidence to develop depression. However, its pathogenesis has not yet been fully elucidated. Here we aimed to investigate the role of inflammatory cytokines in CNP-related anhedonia, which is a core symptom of depression, and to explore the effects of ketamine and parecoxib on pain and anhedonia.

Methods

A rat model of spared nerve injury (SNI) was constructed to mimic CNP. Hierarchical cluster analysis of sucrose preference test (SPT) was applied to classify the SNI rats into anhedonia susceptible and unsusceptible. Inflammatory cytokines in medial prefrontal cortex (mPFC) of brain, serum and L2–5 spinal cord were measured. Moreover, effects of ketamine or parecoxib on mechanical withdrawal test (MWT) and SPT in anhedonia susceptible rats were detected.

Results

Tumor necrosis factor (TNF)-α was increased in mPFC, serum and and spinal cord of anhedonia susceptible rats. Furthermore, anhedonia susceptible and unsusceptible rats both increased the interleukin (IL)-1β level in mPFC, serum and spinal cord. IL-6 was altered in serum and spinal cord, but not in mPFC. IL-10 was significantly altered in mPFC and serum, but not in spinal cord. Additionally, ketamine treatment significantly attenuated the decreased results of MWT and SPT in anhedonia susceptible rats, and that parecoxib significantly improved the MWT score, but failed to alter the result of SPT.

Conclusion

These findings suggest that abnormalities in inflammatory cytokines confer susceptible to anhedonia in a rat model of SNI. Ketamine, a fast-acting antidepressant, has pharmacological benefits to alleviate pain and anhedonia symptoms.

Comparison of ketamine, 7,8-dihydroxyflavone, and ANA-12 antidepressant effects in the social defeat stress model of depression

RATIONALE

Brain-derived neurotrophic factor (BDNF) and signaling at its receptor, tropomyosin-related kinase B (TrkB), are implicated in the rapid and long-lasting antidepressant effects of ketamine. Moreover, a TrkB agonist, 7,8-dihydroxyflavone (7,8-DHF), and/or TrkB antagonist, ANA-12, shows antidepressant effects in animal models of depression.

OBJECTIVE

The objective of this study is to compare the influence of ketamine, 7,8-DHF, and ANA-12 on antidepressant activity in the social defeat stress model.

RESULTS

In the tail suspension and forced swimming tests, ketamine, 7,8-DHF, or ANA-12 markedly attenuated the increased immobility time in depressed mice compared with the vehicle-treated group. In the sucrose preference test, all drugs significantly improved the reduced preference in depressed mice at both 1 and 3 days after a single dose. Antidepressant effect of ketamine, but not 7,8-DHF or ANA-12, was still detectable 7 days after a single dose. Western blot analyses showed that ketamine, but not 7,8-DHF or ANA-12, markedly attenuated reduced levels of BDNF and postsynaptic density protein 95 (PSD-95) in the prefrontal cortex (PFC), dentate gyrus (DG), and CA3 of the hippocampus in depressed mice 8 days after a single dose. Furthermore, ketamine markedly increased reduced levels of GluA1 in the PFC and DG of depressed mice. In contrast, ketamine showed no effect against increased levels of BDNF, PSD-95, and GluA1 observed in the nucleus accumbens of depressed mice.

CONCLUSIONS

Compared with 7,8-DHF and ANA-12, ketamine is a longer-lasting antidepressant in the social defeat stress model, and synaptogenesis may be required for the mechanisms that promote sustained antidepressant effects of ketamine.