Neuroprotective effects of olanzapine on methamphetamine-induced neurotoxicity are associated with an inhibition of hyperthermia and prevention of Bcl-2 decrease in rats

Movement disorders associated with substance use in adults living in precarious housing or homelessness

OBJECTIVE

Many individuals living in precarious housing or homelessness have multimorbid illnesses, including substance use, psychiatric, and neurological disorders. Movement disorders (MDs) associated substance use are amongst the poorly studied subtopics of drug-induced MDs. The aim of the present study was, therefore, to determine the proportion affected and severity of different signs of MDs, as well as their associations with substance use in a community-based sample of precariously housed and homeless individuals.

METHODS

Participants were recruited from an impoverished urban neighborhood and were assessed for substance dependence and self-reported substance use (alcohol, cannabis, cocaine, methamphetamine, nicotine, and opioids), as well as for the severity of signs of MDs (akathisia, dyskinesia, dystonia, and parkinsonism). Adjusted regression models were used to estimate the associations of the severity of signs with the frequency of substance use over the past 4 weeks and with the baseline diagnosis of substance dependence.

RESULTS

The proportion of the sample with clinically relevant signs of MDs in any of the four categories was 18.6% (n = 401), and these participants demonstrated lower levels of functioning than those without signs. Of the different types of substance use, only methamphetamine (its frequency of use and dependence) was significantly associated with greater severity of overall signs of MDs. Frequency of methamphetamine use significantly interacted with age and sex, whereby older female participants exhibited the greatest overall severity with increased methamphetamine use. Of the different signs of MDs, methamphetamine use frequency was positively associated with the severity of trunk/limb dyskinesia and hypokinetic parkinsonism. Relative to no use, concurrent use of antipsychotics demonstrated lower severity of trunk/limb dyskinesia and greater severity of hypokinetic parkinsonism with methamphetamine use, and greater severity of dystonia with cocaine use.

CONCLUSIONS

Our study found a high proportion of MDs in a relatively young sample, and their severity was consistently associated with methamphetamine use, moderated by participant demographics and antipsychotic use. These disabling sequelae represent an important and understudied neurological condition that may affect quality of life and will require further study.

Effects of antipsychotics, haloperidol and olanzapine, on the expression of apoptosis-related genes in mouse mHippoE-2 cells and rat hippocampus

Objective. Modified levels of pro- (caspase3, Bax) and anti-apoptotic (Bcl-2) regulatory proteins have been detected in certain brain areas of schizophrenic patients indicating a possible dysregulation of apoptosis. In the present study, effects of antipsychotics, haloperidol (HAL) and olanzapine (OLA), on the gene expression of caspase3 (casp3), Bax and Bcl-2 were studied in vitro in mouse hippocampal mHippoE-2 cell line and in vivo in the hippocampus of MK-801 animal schizophrenia model with the aim to provide evidence that antipsychotics may affect the activity of apoptosis-related markers. Methods. mHippoE-2 cells were incubated with MK-801 (20 µM), HAL (10 µM), and OLA (10 µM) alone or combined, MK-801+HAL/OLA, for 24, 48, and 72 h. Male Sprague Dawley rats were injected with saline or MK-801 (0.5 mg/kg) for 6 days and since the 7th day, they were treated with vehicle (VEH), HAL (1 mg/kg) or OLA (2 mg/kg) for the next 7 days. The casp3, Bax and Bcl-2 gene expression in mHippoE-2 cells and rat hippocampus was measured by RT-PCR. Results. In mHippoE-2 cells, casp3 gene expression was increased by MK-801 and OLA treatments alone for 48 h, HAL treatment alone for 24 and 72 h, and co-treatment with MK-801+OLA for 24 and 72 h compared to controls. HAL and OLA suppressed the stimulatory effect of MK-801 on casp3 mRNA levels in cells after 48 h of incubation. Bax mRNA levels in mHippoE-2 cells were decreased after HAL treatment for 24 and 48 h, and also after co-treatment with MK-801+HAL for 72 h. In vivo, MK-801 decreased mRNA levels of both pro-apoptotic markers, casp3 and Bax, in hippocampus of VEH-treated rats and Bax mRNA levels in hippocampus of HAL-treated animals. OLA reversed the inhibitory effect of MK-801 on casp3 expression in the VEH-treated animals. Neither MK-801 nor antipsychotics induced changes in the gene expression of anti-apoptotic marker Bcl-2 in mHippoE-2 cells as well as hippocampus of rats. Conclusions. The results of the present study demonstrate that antipsychotics, HAL and OLA, may affect mRNA levels of pro-apoptotic markers in hippocampal cells in vitro, but not in vivo. The obtained data do not clearly support the assumed potentiating role of MK-801 in inducing apoptosis in specific brain areas and a possible protective role of antipsychotics against induction of apoptosis. The obtained data may contribute to a deeper insight into the neurodevelopmental changes connected with schizophrenia.

Molecular mechanisms of programmed cell death in methamphetamine-induced neuronal damage

Methamphetamine, commonly referred to as METH, is a highly addictive psychostimulant and one of the most commonly misused drugs on the planet. Using METH continuously can increase your risk for drug addiction, along with other health complications like attention deficit disorder, memory loss, and cognitive decline. Neurotoxicity caused by METH is thought to play a significant role in the onset of these neurological complications. The molecular mechanisms responsible for METH-caused neuronal damage are discussed in this review. According to our analysis, METH is closely associated with programmed cell death (PCD) in the process that causes neuronal impairment, such as apoptosis, autophagy, necroptosis, pyroptosis, and ferroptosis. In reviewing this article, some insights are gained into how METH addiction is accompanied by cell death and may help to identify potential therapeutic targets for the neurological impairment caused by METH abuse.

The Role of HSP90α in Methamphetamine/Hyperthermia-Induced Necroptosis in Rat Striatal Neurons

Methamphetamine (METH) is one of the most widely abused synthetic drugs in the world. The users generally present hyperthermia (HT) and psychiatric symptoms. However, the mechanisms involved in METH/HT-induced neurotoxicity remain elusive. Here, we investigated the role of heat shock protein 90 alpha (HSP90α) in METH/HT (39.5°C)-induced necroptosis in rat striatal neurons and an in vivo rat model. METH treatment increased core body temperature and up-regulated LDH activity and the molecular expression of canonical necroptotic factors in the striatum of rats. METH and HT can induce necroptosis in primary cultures of striatal neurons. The expression of HSP90α increased following METH/HT injuries. The specific inhibitor of HSP90α, geldanamycin (GA), and HSP90α shRNA attenuated the METH/HT-induced upregulation of receptor-interacting protein 3 (RIP3), phosphorylated RIP3, mixed lineage kinase domain-like protein (MLKL), and phosphorylated MLKL. The inhibition of HSP90α protected the primary cultures of striatal neurons from METH/HT-induced necroptosis. In conclusion, HSP90α plays an important role in METH/HT-induced neuronal necroptosis and the HSP90α-RIP3 pathway is a promising therapeutic target for METH/HT-induced neurotoxicity in the striatum.

Neuroprotective Effect of Pentoxifylline on 3,4-Methylenedioxymethamphetamine-Induced Apoptosis in CA1 Cells of Wistar Rat Hippocampus

Background:

3,4-Methylenedioxymethamphetamine is psychoactive and hallucinogenic and has been shown to produce neurotoxicity both in animals and in humans. Recently, vasodilator drugs such as pentoxifylline (PTX) have been introduced as an alternative with neuroprotective effects. There is no study about the protective effect of PTX on hippocampal apoptosis due to high-dose administration of 3,4-Methylenedioxymethamphetamine (MDMA), so in this study, the protective effect of PTX on the hippocampus of male Wistar rats following high-dose of the drug has been investigated.

Materials and Methods:

Twenty-four male Wistar rats weighing 250-300 g were randomly divided into four groups: control, sham (MDMA injection), experimental (MDMA+PTX injection), and vehicle (MDMA+saline) groups. Two weeks later, the brains were removed and prepared for TUNEL and western blot techniques. Concomitantly the hippocampus was removed to study the change in Bcl-2 and BAX mRNA expression with quantitative real-time polymerase chain reaction.

Results:

Data showed that the number of apoptotic bodies significantly decreased in the experimental group compared to the other groups, except for in control. Also, further investigation revealed that BAX reduced considerably, while Bcl-2 mRNA expression increased dramatically after PTX treatment.

Conclusions:

Our results suggest that PTX may be a neuroprotective agent, and its neuroprotective potential may contribute to reducing the severity of lesions in the hippocampus following a high dose administration of MDMA.

Antipsychotics for Amphetamine Psychosis. A Systematic Review

Background: Among individuals experiencing amphetamine psychosis, it may be difficult to rule out schizophrenia. The use of antipsychotics for the treatment of amphetamine psychosis is sparse due to possible side effects. Some arguments disfavor their use, stating that the psychotic episode is self-limited. Without treatment, some individuals may not fully recover from the psychosis and may develop full-blown psychosis, emotional, and cognitive disturbance. This review aims to investigate the clinical benefits and risks of antipsychotics for the treatment of amphetamine psychosis. Methods: Electronic search on trials on antipsychotic drugs for amphetamine psychosis from their inception to November 2018 was conducted in PubMed, Scopus, Google Scholar, EBSCOhost, ProQuest, Cochrane Review Database, Medline Ovid, and EMBASE following the Preferred Reporting Items for Systematic Reviews and Meta-Analysis guidelines. The Cochrane risk-of-bias tool assessed the risk of bias, the methodological quality of individual trials was assessed by the Oxford Quality Scoring System, and the quality of evidence for recommendations was judged by the Grading of Recommendations, Assessment, Development, and Evaluations (GRADE). The results were synthesized qualitatively and quantitatively. Results: The investigation of six randomized controlled trials of 314 participants showed that aripiprazole, haloperidol, quetiapine, olanzapine, and risperidone were able to reduce or control the psychotic episode (positive and negative symptoms) induced by amphetamine use with no adverse event. Although the side-effect profile of these agents varied, no drug was clinically superior to others. Conclusions: This review suggests that antipsychotics seem to be efficacious for amphetamine psychosis on both positive and negative symptoms. Practitioners need to tailor their use based on risks for side effects individually.

Brain Sub/Region-Specific Effects of Olanzapine on c-Fos Expression of Chronically Socially Isolated Rats

Olanzapine (Olz) is an atypical antipsychotic used to treat depression, anxiety and schizophrenia, which can be caused by chronic psychosocial stress. c-Fos protein expression has been used as an indirect marker of neuronal activity in response to various forms of stress or pharmacological treatments. We examined the effects of a 3-week treatment of Olz (7.5 mg/kg/day) on c-Fos protein expression in stress-relevant brain sub/regions, its relationship with isolation-induced behavioral changes, and potential sites of Olz action on control and male rats exposed to 6 weeks of chronic social isolation (CSIS), an animal model of depression. Olz treatment reversed depression- and anxiety-like behaviors induced by CSIS and suppressed a CSIS-induced increase in the number of c-Fos-positive cells in subregions of the dorsal hippocampus, ventral (v) DG, retrosplenial cortex, and medial prefrontal cortex. In contrast, no change in c-Fos expression was seen in the CA3v, amygdala and thalamic, hypothalamic or striatal subregions in Olz-treated CSIS rats, suggesting different brain sub/regions' susceptibility to Olz. An increased number of c-Fos-positive cells in the CA1v, amygdala and thalamic, hypothalamic and striatal subregions in controls as well as in the CA1v and subregion of the hypothalamus and nucleus accumbens in Olz-treated CSIS rats was found. Results suggest the activation of brain sub/regions following CSIS that may be involved in depressive and anxiety-like behaviors. Olz treatment showed region-specific effects on neuronal activation. Our data contribute to a better understanding of the mechanisms underlying the CSIS response and potential brain targets of Olz in socially isolated rats.

Olanzapine and haloperidol for the treatment of acute symptoms of mental disorders induced by amphetamine-type stimulants: A randomized controlled trial

BACKGROUND

This study aimed to compare olanzapine and haloperidol efficacies in the treatment of acute psychiatric symptoms due to amphetamine-type stimulants (ATSs).

METHODS

The Zelen II design method was used; 124 patients with acute mental disorders due to amphetamine were randomly divided into olanzapine group (n = 63) and haloperidol group (n = 61). Then, a 4-week open-label medical therapy was performed. Clinical Global Impression Scale Item 2 was employed to evaluate the onset time; meanwhile, Brief Psychiatric Rating Scale (BPRS) was used at baseline and at posttreatment weeks 1, 2, and 4. Moreover, adverse reactions during the treatment were recorded.

RESULTS

Onset time in the olanzapine group was significantly earlier than in the haloperidol group; BPRS scores in the olanzapine group were significantly lower than haloperidol group values at 1 and 2 weeks of treatment. The overall effective rates had no statistically significant difference.

CONCLUSION

Short-term olanzapine and haloperidol treatments had equivalent efficacies in the treatment of acute symptoms of mental disorders due to ATSs; however, olanzapine administration resulted in relatively earlier disease onset, with less adverse reactions.

Functional Changes of Orexinergic Reaction to Psychoactive Substances

It is becoming increasingly apparent the importance of the central nervous system (CNS) as the major contributor to the regulation of systemic metabolism. Antipsychotic drugs are used often to treat several psychiatric disorders, including schizophrenia and bipolar disorder However, antipsychotic drugs prescription, particularly the second-generation ones (SGAs), such as clozapine and olanzapine, is related to a considerable weight gain which usually leads to obesity. The aim of this paper is to assess the influence of orexin A on sympathetic and hyperthermic reactions to several neuroleptic drugs. Orexin A is a neuropeptide which effects both body temperature and food intake by increasing sympathetic activity. Orexin A-mediated hyperthermia is reduced by haloperidol and is blocked by clozapine and olanzapine. Orexin A-mediated body temperature elevation is increased by risperidone. These hyperthermic effects are delayed by quietapine. In this paper, it is discussed the orexinergic pathway activation by neuroleptic drugs and its influence on human therapeutic strategies. With the aim to determine that neuroleptic drugs mediate body temperature control through to the orexinergic system, we summarized our previously published data. Psychiatric disorders increase the risk of developing metabolic disorders (e.g., weight gain, increased blood pressure, and glucose or lipid levels). Therefore, the choice of antipsychotic drug to be prescribed, based on the relevant risks and benefits of each individual drug, has an essential role in human health prevention.

The Mediating Role of A2A Adenosine Receptors in the Mitochondrial Pathway of Apoptotic Hippocampal Cell Death, Following the Administration of MDMA in Rat

Introduction:

The 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) is a popular recreational drug and a major source of substance abuse, which ultimately leads to sensations of well-being, elation and euphoria, moderate derealization/depersonalization, and cognitive disruptions, as well as intense sensory awareness. The mechanisms involved in memory impairment induced by MDMA are not completely understood.

Methods:

The current study used 40 Sprague-Dawley rats, weighted 200 to 250 g. Experiments were performed in four groups, each containing 10 rats. The first group of rats was used as the control, treated with dimethyl sulfoxide (DMSO). The second group was treated with MDMA. The third group was treated with MDMA and CGS (the adenosine A_2A receptor agonist, 2-[p-(2-carboxyethyl) phenethylamino]-5′-N-ethylcarboxamidoadenosine) (CGS 21680) and the fourth group was treated with MDMA and SCH (the A_2A receptor antagonist [7-(2-phenylethyl)-5-amino-2-(2-furyl-) pyrazolo-[4, 3-e]-1, 2, 4 triazolo [1,5-] pyrimidine]) (SCH 58261). The drugs in all groups were administrated intraperitoneally (i.p.) once a day for 7 days. In 5 rats of each group, following perfusion, samples were taken from hippocampi to investigate apoptosis. Accordingly, the samples were stained using the terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) assay kit, and studied by light microscopy. In other rats, fresh tissue was also removed to study the expression of bax and bcl-2 by Western blotting technique.

Results:

It was observed that the coadministration of MDMA with CGS reduced bax expression and prevented apoptosis of hippocampal cells. The coadministration of MDMA and SCH increased bax expression, and also increased the frequency of hippocampal cell apoptosis.

Conclusion:

The results of the current study showed that administration of CGS with MDMA decreased the common side effects associated with MDMA.

Novel imatinib-loaded silver nanoparticles for enhanced apoptosis of human breast cancer MCF-7 cells

In the current study, in vitro biological feature of imatinib-loaded silver nanoparticles (IMAB-AgNPs) on human breast cancer cell line was investigated. The formation of synthesized silver nanoparticles (AgNPs) was characterized by UV-Visible spectroscopy, EDS, TEM imaging, SEM, FTIR, DLS and Zeta potentiometer. The developed IMAB-AgNPs with maximum percentage of loading efficiency was demonstrated in the average of 130 nm and mostly spherical. Additionally, in vitro drug release study showed a slow and continuous release of imatinib over a period of 80 h. We demonstrated that the synthesized IMAB-AgNPs exhibited a dose-dependent cytotoxicity against MCF-7 cell line. Then, real-time PCR method was also applied for the investigation of Bax and Bcl-2 gene expression in the cells. Comparing IMAB-AgNPs to AgNPs and Imatinib revealed the ability of IMAB-AgNPs to up-regulating Bax/Bcl-2 ratio. An induction of apoptosis was evidenced by Annexin-V/PI detection assay. Based on the current obtained data, the IMAB-AgNPs can exhibit inhibitory effect on viability through up regulation of apoptosis in MCF-7 cancer cells, which provides influencing evidence for the green synthesized AgNPs as a promising sustained drug delivery system.

Drug-induced neurotoxicity in addiction medicine: From prevention to harm reduction

Neurotoxicity is considered as a major cause of neurodegenerative disorders. Most drugs of abuse have nonnegligible neurotoxic effects many of which are primarily mediated by several dopaminergic and glutamatergic neurotransmitter systems. Although many researchers have investigated the medical and cognitive consequences of drug abuse, the neurotoxicity induced by these drugs still requires comprehensive attention. The science of neurotoxicity promises to improve preventive and therapeutic strategies for brain disorders such as Alzheimer disease and Parkinson's disease. However, its clinical applications for addiction medicine remain to be defined adequately. This chapter reviews the most commonly discussed mechanisms underlying neurotoxicity induced by common drugs of abuse including amphetamines, cocaine, opiates, and alcohol. In addition, the known factors that trigger and/or predispose to drug-induced neurotoxicity are discussed. These factors include drug-related, individual-related, and environmental insults. Moreover, we introduce some of the potential pharmacological antineurotoxic interventions deduced from experimental animal studies. These interventions involve various targets such as dopaminergic system, mitochondria, cell death signaling, and NMDA receptors, among others. We conclude the chapter with a discussion of addicted patients who might benefit from such interventions.

Psychopharmacology of atypical antipsychotic drugs: From the receptor binding profile to neuroprotection and neurogenesis

The original definition of atypical antipsychotic drugs (APD) was drugs that are effective against positive symptoms in schizophrenia with no or little extrapyramidal symptoms (EPS). However, atypical APD have been reported to be more effective for cognitive dysfunction and negative symptoms in schizophrenia than typical APD, which expands the definition of 'atypicality'. This article provides a critical review of the pharmacology of atypical APD, especially from the viewpoint of receptor binding profiles and neurotransmitter regulations as well as neuroprotection and neurogenesis. A variety of serotonin (5-HT) receptors, such as 5-HT2A / 2C , 5-HT1A , 5-HT6 and 5-HT7 receptors, may contribute to the mechanisms of action of 'atypicality'. The dopaminergic modulations, including a low affinity for dopamine D2 receptors and a partial D2 receptor agonistic action, and glutamatergic regulations may also be involved in the pharmacological backgrounds of 'atypicality'. Atypical APD, but not typical APD, may facilitate cortical neuroprotection and hippocampal neurogenesis, which might be a part of the action mechanisms of atypical APD. The facilitation of cortical neuroprotection and hippocampal neurogenesis induced by atypical APD might be mediated by an increase in the Ser9 phosphorylation of glycogen synthase kinase-3β (GSK-3β). The stimulation of 5-HT1A receptors and/or the blockade of 5-HT2 receptors, which is characteristic of atypical APD, might increase Ser9 phosphorylation of GSK-3β. Moreover, atypical APD increase brain-derived neurotrophic factor (BDNF) levels. BDNF increases Ser9 phosphorylation of GSK-3β and has neuroprotective and neurogenic effects, as in the case of atypical APD. These findings suggest that GSK-3β might play a role in the action mechanisms of atypical APD, in both the 5-HT-dependent and BDNF-dependent mechanisms.

Methamphetamine-induced toxicity: an updated review on issues related to hyperthermia

Reports of methamphetamine-related emergency room visits suggest that elevated body temperature is a universal presenting symptom, with lethal overdoses generally associated with extreme hyperthermia. This review summarizes the available information on methamphetamine toxicity as it pertains to elevations in body temperature. First, a brief overview of thermoregulatory mechanisms is presented. Next, central and peripheral targets that have been considered for potential involvement in methamphetamine hyperthermia are discussed. Finally, future areas of investigation are proposed, as further studies are needed to provide greater insight into the mechanisms that mediate the alterations in body temperature elicited by methamphetamine.

Neuroprotective effects of olanzapine in N-methyl-D-aspartate-induced retinal injury

PURPOSE

The aim of this study was to investigate the neuroprotective effect of olanzapine (OLA), an atypical antipsychotic drug, on N-methyl-d-aspartate (NMDA)-induced retinal injury.

METHODS

Retinal neuronal ischemia was induced by NMDA in Wistar rats. OLA was administered intraperitoneally in 2 different dosages: 2 and 12 mg/kg. At the end of 2 weeks of OLA treatment, 1 eye of each animal was enucleated for histopathologic examination. We also measured malondialdehyde (MDA) levels in retinal homogenates as a marker of ischemic injury.

RESULTS

The retinal ganglion cell (RGC) count was significantly higher in cases where we used OLA 2 mg/kg or OLA 12 mg/kg compared to the control group (P=0.0032 and P=0.0005, respectively). We also found that MDA was significantly reduced by OLA 2 mg/kg or OLA 12 mg/kg compared to the control group (P=0.0001 and P=0.0001, respectively). There was no statistically significant difference between OLA 2 mg/kg or OLA 12 mg/kg groups in terms of RGC count and MDA levels (P>0.05 for all).

CONCLUSION

Our data showed that OLA preserved RGCs from NMDA-induced retinal injury; thus, it may have potential neuroprotective effects.

Myelination deficit in a phencyclidine-induced neurodevelopmental model of schizophrenia

Increasing evidence supports an important role of oligodendrocytes and myelination in the pathogenesis of schizophrenia. Oligodendrocytes are the myelin-producing cells in the central nervous system. To test the myelination dysfunction hypothesis of schizophrenia, possible myelination dysfunction was evaluated in a phencyclidine (PCP)-induced neurodevelopmental model of schizophrenia. On postnatal day (PND) 2, rat pups were treated with a total 14 subcutaneous daily injections of PCP (10mg/kg) or saline. PCP-injected rats showed schizophrenia-like behaviors including hyper-locomotor activity on PND 30 and prepulse inhibition deficit on PND 31. Cerebral myelination was measured by the expression of myelin basic protein (MBP), and cerebral mature oligodendrocytes were measured by the expression of glutathione S-transferase (GST)-π in rats. The results indicate that the expressions of MBP on PND 16, 22 and 32 and GST-π on PND 22 decreased in the frontal cortex of PCP-injected rats. Our results suggest that there was myelination impairment in the phencyclidine-induced schizophrenia animal model, and indicate that myelination may play an important role in the pathogenesis of schizophrenia.

Antipsychotics in the treatment of bipolar disorder

Atypical antipsychotics have an important role in the acute and maintenance treatment of bipolar disorder. While robust evidence supports the efficacy of these agents in the treatment of mania and in the prevention of manic relapse, few atypical antipsychotics have shown efficacy in the treatment or prevention of depressive episodes. These agents pose a lower risk of extrapyramidal side effects compared to typical neuroleptics, but carry a significant liability for weight gain and other metabolic side effects such as hyperglycemia and hyperlipidemia. More comparative effectiveness studies are needed to assess the optimal treatment regimens, including the relative benefits and risks of antipsychotics versus mood stabilizers. The exploration of the molecular mechanisms of antipsychotics has helped to shed further light on the underlying neurobiology of bipolar disorder, since these compounds target systems thought to be key to the pathophysiology of bipolar disorder. In addition to modulating monoaminergic neurotransmission, atypical antipsychotics appear to share properties with mood-stabilizing agents known to alter intracellular signal transduction leading to changes in neuronal activity and gene expression. Atypical antipsychotic drugs have been shown to exhibit neuroprotective properties that are mediated by upregulation of trophic and cellular resilience factors. Building on our understanding of existing therapeutics, especially as it relates to underlying disease pathology, newer "plasticity enhancing" strategies hold promise for future treatments of bipolar disorder.

Structure-based discovery of low molecular weight compounds that stimulate neurite outgrowth and substitute for nerve growth factor

Olanzapine, an atypical antipsychotic drug, was previously shown to protect neuronal cells against nutrient deprivation and to enhance neurite outgrowth. In an effort to identify small molecules with greater potency, the structure of olanzapine was used as a template to search commercially available chemical inventories for compounds with similar features. These compounds were evaluated for their ability to protect cells against glutamine deprivation and low-serum conditions. Positive compounds, 'hits' from initial screening, were then tested for stimulation of neurite outgrowth, alone and in combination with suboptimum concentrations of nerve growth factor (NGF). Numerous neuroprotective compounds (mw < 550 Da) were identified that significantly stimulated neurite outgrowth in PC12 cells. These included 4', 6'-diamidino-2-phenylindole, a nuclear stain; staurosporine, an antibiotic and kinase inhibitor; and 2-phenylamino-adenosine, an adenosine analog. The small molecules were comparable with NGF, and in fact, replaced NGF in outgrowth assays. Pharmacophore analysis of the hits led to the design and synthesis of an active compound, LSU-D84, which represented an initial lead for drug discovery efforts.

Methamphetamine toxicity and messengers of death

Methamphetamine (METH) is an illicit psychostimulant that is widely abused in the world. Several lines of evidence suggest that chronic METH abuse leads to neurodegenerative changes in the human brain. These include damage to dopamine and serotonin axons, loss of gray matter accompanied by hypertrophy of the white matter and microgliosis in different brain areas. In the present review, we summarize data on the animal models of METH neurotoxicity which include degeneration of monoaminergic terminals and neuronal apoptosis. In addition, we discuss molecular and cellular bases of METH-induced neuropathologies. The accumulated evidence indicates that multiple events, including oxidative stress, excitotoxicity, hyperthermia, neuroinflammatory responses, mitochondrial dysfunction, and endoplasmic reticulum stress converge to mediate METH-induced terminal degeneration and neuronal apoptosis. When taken together, these findings suggest that pharmacological strategies geared towards the prevention and treatment of the deleterious effects of this drug will need to attack the various pathways that form the substrates of METH toxicity.

Neuroprotective effect of atypical antipsychotics in cognitive and non-cognitive behavioral impairment in animal models

Antipsychotic drugs are divided into two groups: typical and atypical. Recent clinical studies show atypical antipsychotics have advantages over typical antipsychotics in a wide variety of neuropsychiatric conditions, in terms of greater efficacy for positive and negative symptoms, beneficial effects on cognitive functioning, and fewer extra pyramidal side effects in treating schizophrenia. As such, atypical antipsychotics may be effective in the treatment of depressive symptoms associated with psychotic and mood disorders, posttraumatic stress disorder and psychosis in Alzheimer disease. In this paper, we describe the effects and potential neurochemical mechanisms of action of atypical antipsychotics in several animal models showing memory impairments and/or non-cognitive behavioral changes. The data provide new insights into the mechanisms of action of atypical antipsychotics that may broaden their clinical applications.

Antipsychotic drugs: comparison in animal models of efficacy, neurotransmitter regulation, and neuroprotection

Various lines of evidence indicate the presence of progressive pathophysiological processes occurring within the brains of patients with schizophrenia. By modulating chemical neurotransmission, antipsychotic drugs may influence a variety of functions regulating neuronal resilience and viability and have the potential for neuroprotection. This article reviews the current literature describing preclinical and clinical studies that evaluate the efficacy of antipsychotic drugs, their mechanism of action and the potential of first- and second-generation antipsychotic drugs to exert effects on cellular processes that may be neuroprotective in schizophrenia. The evidence to date suggests that although all antipsychotic drugs have the ability to reduce psychotic symptoms via D(2) receptor antagonism, some antipsychotics may differ in other pharmacological properties and their capacities to mitigate and possibly reverse cellular processes that may underlie the pathophysiology of schizophrenia.

Toxicokinetics and toxicodynamics of paraquat accumulation in mouse brain

Paraquat (PQ) is a potential human neurotoxicant and is used in models of oxidative stress. We determined the toxicokinetics (TK) and toxicodynamics (TD) of PQ in adult mouse brain following repeated or prolonged PQ exposure. PQ accumulated in different brain regions and reached a plateau after approximately 18 i.p. (10 mg/kg) doses and resulted in modest morbidity and mortality unpredictably associated with dose interval and number. PQ had divergent effects on horizontal locomotor behavior depending on the number of doses. PQ decreased striatal dopamine levels after the 18th to 36th i.p. dose (10 mg/kg) and reduced the striatal level of tyrosine hydroxylase. Drinking water exposure to PQ (0.03- 0.05 mg/ml) did not result in any mortality and resulted in concentration and time dependent levels in the brain. The brain half-life of PQ varied with mouse strain. PQ accumulates and may saturate a site in mouse brain resulting in complex PQ level and duration-related consequences. These findings should alter our risk assessment of this compound and demonstrate a useful, but complex dynamic model for understanding the consequences of PQ in the brain.

Erythropoietin prevents haloperidol treatment-induced neuronal apoptosis through regulation of BDNF

Functional alterations in the neurotrophin, brain-derived neurotrophic factor (BDNF) have recently been implicated in the pathophysiology of schizophrenia. Furthermore, animal studies have indicated that several antipsychotic drugs have time-dependent (and differential) effects on BDNF levels in the brain. For example, our previous studies in rats indicated that chronic treatment with the conventional antipsychotic, haloperidol, was associated with decreases in BDNF (and other neurotrophins) in the brain as well as deficits in cognitive function (an especially important consideration for the therapeutics of schizophrenia). Additional studies indicate that haloperidol has other deleterious effects on the brain (eg increased apoptosis). Despite such limitations, haloperidol remains one of the more commonly prescribed antipsychotic agents worldwide due to its efficacy for the positive symptoms of schizophrenia and its low cost. Interestingly, the hematopoietic hormone, erythropoietin, in its recombinant human form rhEPO has been reported to increase the expression of BDNF in neuronal tissues and to have neuroprotective effects. Such observations provided the impetus for us to investigate in the present study whether co-treatment of rhEPO with haloperidol could sustain the normal levels of BDNF in vivo in rats and in vitro in cortical neuronal cultures and further, whether BDNF could prevent haloperidol-induced apoptosis through the regulation of key apoptotic/antiapoptotic markers. The results indicated that rhEPO prevented the haloperidol-induced reduction in BDNF in both in vivo and in vitro experimental conditions. The sustained levels of BDNF in rats with rhEPO prevented the haloperidol-induced increase in caspase-3 (p<0.05) and decrease in Bcl-xl (p<0.01) protein levels. Similarly, in vitro experiments showed that rhEPO prevented (p<0.001) the haloperidol-induced neuronal cell death as well as the decrease in Bcl-xl levels (p<0.01). These findings may have significant implications for the development of neuroprotective strategies to improve clinical outcomes when antipsychotic drugs are used chronically.

Hyperthermic and lethal effects of methamphetamine: roles of dopamine D1 and D2 receptors

Both human and animal studies suggest that hyperthermia contributes to the lethal effects of methamphetamine. To elucidate the roles of dopamine D1 and D2 receptors in methamphetamine-induced hyperthermia and lethal effects, we used D1 knockout (D1KO) mice, D2 knockout (D2KO) mice, and wild-type littermates. After the administration (i.p.) of a single dose of 30 mg/kg methamphetamine, no hyperthermic effect on body temperature was observed in D2KO mice, though there was a slight elevation in D1KO mice and a marked elevation in wild-type mice. Approximately 27% of the wild-type mice died after the administration, compared to only 7% of D1KO mice and 4% of D2KO mice. In conclusion, both D1 and D2 receptors play roles in the lethal toxic effects of methamphetamine, and mainly the D2 receptor is involved in the elevation of body temperature.

Protective effects of olanzapine and haloperidol on serum withdrawal-induced apoptosis in SH-SY5Y cells

PURPOSE

Recent clinical studies have suggested that treatment with second generation antipsychotic drugs such as olanzapine may prevent progressive alterations of brain structure in patients with schizophrenia. However, the molecular mechanisms underlying these different effects remain to be determined. We investigated the mechanisms of action of olanzapine and haloperidol, on serum withdrawal apoptosis in human neuroblastoma SH-SY5Y cells.

METHODS

SH-SY5Y cells were cultured with olanzapine and haloperidol in medium with or without serum. We determined the effects of the drugs on cell viability against serum withdrawal by 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay. Additionally, to explore the drugs' actions, Western blot was performed to examine the expression of key genes involved in GSK-3beta-mediated signaling, notably GSK-3beta, beta-catenin, and Bcl-2.

RESULTS

SH-SY5Y cells suffered about a 38% loss in cell number under serum-free conditions for 48 h. Olanzapine (10-200 muM) up to 100 muM significantly attenuated serum withdrawal-induced cell loss (p<0.01), and a dose of 100 muM also increased cell viability (p<0.05). In contrast, haloperidol (0.01-10 muM) did not affect cell viability but exacerbated cell death at 10 muM under serum-free conditions (p<0.01). Western blot analysis showed that olanzapine, but not haloperidol, prevented the serum withdrawal-induced decrease in levels of neuroprotective proteins such as p-GSK-3beta, beta-catenin, and Bcl-2 (p<0.01), whereas haloperidol robustly reduced the levels of these proteins at a 10 muM dose in serum-starved cells (p<0.05). Moreover, olanzapine alone significantly increased phosphorylation of GSK-3beta under normal conditions (p<0.05).

CONCLUSIONS

This study showed that olanzapine may have neuroprotective effects, whereas haloperidol was apparently neurotoxic. The actions of signaling systems associated with GSK-3beta may be key targets for olanzapine and haloperidol, but their effects are distinct. These differences suggest different therapeutic effects of first and second generation antipsychotic drugs in patients with schizophrenia.

Beneficial effects of quetiapine in a transgenic mouse model of Alzheimer's disease

Previous studies have suggested that quetiapine, an atypical antipsychotic drug, may have beneficial effects on cognitive impairment, and be a neuroprotectant in treating neurodegenerative diseases. In the present study, we investigated the effects of quetiapine on memory impairment and pathological changes in an amyloid precursor protein (APP)/presenilin-1 (PS-1) double transgenic mouse model of Alzheimer's disease (AD). Non-transgenic and transgenic mice were treated with quetiapine (0, 2.5, or 5mg/(kg day)) for 1, 4, and 7 months in drinking water from the age of 2 months. After 4 and 7 months of continuous quetiapine administration, memory impairment was prevented, and the number of beta-amyloid (Abeta) plaques decreased in the cortex and hippocampus of the transgenic mice. Quetiapine also decreased brain Abeta peptides, beta-secretase activity and expression, and the level of C99 (an APP C-terminal fragment following cleavage by beta-secretase) in the transgenic mice. Furthermore, quetiapine attenuated anxiety-like behavior, up-regulated cerebral Bcl-2 protein, and decreased cerebral nitrotyrosine in the transgenic mice. These findings suggest that quetiapine can alleviate cognitive impairment and pathological changes in an APP/PS1 double transgenic mouse model of AD, and further indicate that quetiapine may have preventive effects in the treatment of AD.

Olanzapine blocks the sympathetic and hyperthermic reactions due to cerebral injection of orexin A

Since experiments regarding a possible relation between olanzapine and orexin A has been scarcely reported in international literature, this experiment tested the effect of olanzapine on the sympathetic and thermogenic effects induced by orexin A. The firing rates of the sympathetic nerves to interscapular brown adipose tissue (IBAT), along with IBAT, colonic temperatures and heart rate were monitored in urethane-anesthetized male Sprague-Dawley rats before an injection of orexin A (1.5 nmol) into the lateral cerebral ventricle and over a period of 150 min after the injection. The same variables were monitored in rats with an intraperitoneal administration of olanzapine (10mg/kg bw), injected 30 min before the orexin administration. The results show that orexin A increases the sympathetic firing rate, IBAT, colonic temperatures and heart rate. This increase is blocked by the injection of olanzapine. These findings indicate that olanzapine affects the complex reactions related to activation of orexinergic system.

Methamphetamine-induced hyperthermia and lethal toxicity: role of the dopamine and serotonin transporters

We examined the hyperthermic and lethal toxic effects of methamphetamine in dopamine transporter (DAT) and/or serotonin transporter (SERT) knockout (KO) mice. Methamphetamine (45 mg/kg) caused significant hyperthermia even in the mice with a single DAT gene copy and no SERT copies (DAT+/- SERT-/- mice). Mice with no DAT copies and a single SERT gene copy (DAT-/- SERT+/- mice) showed significant but reduced hyperthermia when compared to wild-type mice after methamphetamine. Surprisingly, DAT/SERT double KO mice exhibited a paradoxical hypothermia after methamphetamine. These results demonstrate that methamphetamine exerts a hyperthermic effect via DAT, or via SERT, in the absence of DAT. The selective norepinephrine transporter blocker (20 mg/kg nisoxetine) caused hyperthermia in DAT/SERT double KO mice, suggesting that the norepinephrine system is not responsible for methamphetamine-induced paradoxical hypothermia in the double KO mice. DAT gene deletion in mice strikingly increased LD50 of methamphetamine by 1.7-1.8 times that of wild-type mice, suggesting that the lethal toxic effect of methamphetamine is mainly dependent on DAT. Moreover, dissociation between hyperthermic and lethal toxic effects of methamphetamine in DAT single KO mice and DAT/SERT double KO mice suggest that hyperthermia is not a prerequisite for methamphetamine-induced lethality. Methamphetamine (45 mg/kg) significantly increased mRNA of interleukin-1beta, which is the major endogenous pyrogen, in the hypothalamus of wild-type mice but not in DAT/SERT double KO mice, which provides a partial mechanism of methamphetamine-induced paradoxical hypothermia. These results suggest that DAT and SERT are key molecules for hyperthermic and lethal toxic effects of methamphetamine.

Possible Mechanisms of Neurodegeneration in Schizophrenia

Brain morphological alterations in schizophrenic patients have led to the neurodevelopmental hypothesis of schizophrenia. On the other hand, a progressive neurodegenerative process has also been suggested and some follow-up studies have shown progressive morphological changes in schizophrenic patients. Several neurotransmitter systems have been suggested to be involved in this disorder and some of them could lead to neuronal death under certain conditions. This review discusses some of the biochemical pathways that could lead to neurodegeneration in schizophrenia showing that neuronal death may have a role in the etiology or natural course of this disorder.

The effects of chronic administration of quetiapine on the methamphetamine-induced recognition memory impairment and dopaminergic terminal deficit in rats

Previous studies have suggested that quetiapine, a new atypical antipsychotic drug, may have beneficial effects on cognitive impairment and be a neuroprotectant in treating neurodegenerative diseases. In the present study, we investigated the therapeutic effects of chronic administration of quetiapine on methamphetamine (METH)-induced recognition memory impairment and dopaminergic terminal neurotoxicity in rats. Rats were pretreated with METH (5 mg/kg; s.c.) four times at 2-h intervals while their body temperature was monitored. Fifteen minutes after the last METH injection, rats were administered quetiapine (10 mg/kg/day; i.p.) for 28 days. One day after the last quetiapine injection, rats were trained and tested on an object recognition task on days 29 and 30. Finally, on day 31, rats were sacrificed for immunohistochemistry, 1 day after the object recognition task. METH induced hyperthermia, recognition memory impairment and a decrease of tyrosine hydroxylase immunoreactivity in the caudate putamen (CPu) of striatum. Quetiapine attenuated the METH-induced hyperthermia. Furthermore, chronic post-treatment of quetiapine reversed the METH-induced memory impairment and dopaminergic terminal deficit. These findings suggest that quetiapine may have therapeutic effects in the treatment of cognitive impairment and neurodegeneration induced by METH.

The effects of chronic administration of quetiapine on the phencyclidine-induced reference memory impairment and decrease of Bcl-XL/Bax ratio in the posterior cingulate cortex in rats

Quetiapine, a new atypical antipsychotic drug, effectively alleviates positive and negative symptoms, as well as cognitive impairment that may be caused by neurodegeneration, in schizophrenia patients. Earlier in vivo and in vitro studies have demonstrated that quetiapine may be a neuroprotectant. The present study was designed to examine the beneficial effects of quetiapine on the possible cognitive impairment and changes of brain apoptotic regulation proteins induced by phencyclidine (PCP) in rats. Rats were treated with quetiapine (10 mg/kg/day; intraperitoneal (i.p.)) or vehicle for 16 days. On day 14, 1 h after the administration of quetiapine, the rats were given PCP (50 mg/kg; subcutaneous (s.c.)) or vehicle. Then quetiapine was administrated for an additional 2 days. One day after the last quetiapine injection (3 days after the PCP injection), the rats were trained on a spatial memory task in a radial arm maze. After the behavioural test, the rats were decapitated for Western blot analysis. PCP induced reference memory impairment, and a decrease of the ratio of an anti-apoptotic Bcl-2 family member (Bcl-XL) to a pro-apoptotic analogue (Bax) in the posterior cingulate cortex. Chronic administration of quetiapine counteracted the PCP-induced reference memory impairment and decrease of Bcl-XL/Bax ratio in the posterior cingulate cortex. These results suggest that quetiapine may have ameliorating effects on the cognitive impairment and brain apoptotic processes induced by PCP.

Single or multiple injections of methamphetamine increased dopamine turnover but did not decrease tyrosine hydroxylase levels or cleave caspase-3 in caudate-putamen

Methamphetamine (METH), leading to striatal dopamine (DA) nerve terminal toxicity in mammals, is also thought to induce apoptosis of striatal neurons in rodents. We investigated the acute effects induced by multiple injections of METH (4 x 5 mg/kg, i.p.) at 2-h intervals or a single injection of METH (20 mg/kg, i.p.) on terminal dopaminergic toxicity markers, including DA levels, DA turnover, and tyrosine hydroxylase (TH) immunoreactivity in rat caudate-putamen (CPu). We further investigated whether both treatment paradigms would change Bax and activate caspase-3 expression, thus triggering striatal apoptotic mitochondria-dependent biochemical cascades. The first injection of METH (5 mg/kg, i.p.) produced a significant release of DA that peaked 30 min and stayed above control levels up to 1.5 h within CPu. In another set of experiments, rats were killed 1 and 24 h following the last injection, for tissue DA and metabolite content measurement and Western blot analysis (24 h). Multiple doses induced DA depletion and increased turnover at both endpoints. Single-dose METH reproduced these effects at 24 h; however, turnover was significantly higher than that evoked by the multiple doses at 24 h. Although both paradigms evoked similar DA depletion, however, none of the dosing regimens induced changes in TH expression at 24 h. The former paradigm produced an increase in Bax expression in CPu not sufficient to induce cleavage of caspase-3 proenzyme at 24 h. This study suggests that both paradigm induced changes in striatal dopaminergic markers that are independent of terminal degeneration and striatal apoptotic mitochondria-dependent caspase-3 driven cascade within 24 h.

Quetiapine reverses the suppression of hippocampal neurogenesis caused by repeated restraint stress

Quetiapine is an atypical antipsychotic effective in treating the positive, negative, and cognitive symptoms of patients with schizophrenia. Our previous study has shown that chronic administration of quetiapine attenuates the decrease in levels of brain-derived neurotrophic factor (BDNF) in the hippocampi of rats subjected to chronic-restraint stress. In the present study, we investigated the effects of quetiapine on hippocampal neurogenesis that had been compromised in stressed rats. Newborn cells in the hippocampus were labeled by bromodeoxyuridine (BrdU), and immature neurons were detected immunohistochemically using an antibody against phosphorylated cAMP response element-binding protein (pCREB). The restrained rats (4 h/day for 7 days) showed lower levels of hippocampal neurogenesis indicated by decreased numbers of BrdU-labeled and pCREB-positive cells. Post-stress administration of quetiapine (10 mg/kg) for 7 or 21 days reversed the stress-induced suppression of hippocampal neurogenesis, evidenced in the numbers of BrdU-labeled and pCREB-positive cells that are comparable to those in non-stressed rats but higher than those in the vehicle-treated rats. The results may help us understand the therapeutic effects of quetiapine on cognitive deficits in patients with schizophrenia and depression, in which the structure and functions of the hippocampus are implicated.

Second-generation antipsychotic drugs, olanzapine, quetiapine, and clozapine enhance neurite outgrowth in PC12 cells via PI3K/AKT, ERK, and pertussis toxin-sensitive pathways

Second-generation antipsychotic drugs, olanzapine, quetiapine, and clozapine, were found to enhance neurite outgrowth induced by nerve growth factor (NGF) in PC12 cells. These drugs increased the number of cells bearing neurites, the length of primary neurites, and the size of the cell body of NGF-differentiated PC12 cells. In addition, the drugs induced sprouting of neurite-like processes in PC12 cells in the absence of NGF. Olanzapine, quetiapine, and clozapine enhanced the phosphorylation of Akt and ERK in combination with NGF, and specific inhibitors of these pathways attenuated these effects. Pretreatment of cells overnight with pertussis toxin had no effect on NGF-induced differentiation but significantly decreased the effects of the antipsychotic drugs on neurite outgrowth, suggesting that Gi/Go-coupled receptors are involved in the response to drug. A better understanding of the mechanisms underlying the effects of the second-generation drugs might suggest new therapeutic targets for enhancement of neurite outgrowth.

Olanzapine attenuates the okadaic acid-induced spatial memory impairment and hippocampal cell death in rats

It is hypothesized that olanzapine, an atypical antipsychotic drug, has beneficial effects on cognitive impairment and neuropathological changes in treating neurodegenerative diseases. In the present study, we investigated the effects of chronic administration of olanzapine on the spatial memory impairment and hippocampal cell death induced by the direct injection of okadaic acid (OA), a potent neurotoxin, into the rat hippocampus. After being pretreated with olanzapine (0.5 or 2 mg/kg/day, i.p.) for 2 weeks, the rats were unilaterally microinjected with OA (100 ng) into the hippocampus, and then were continuously administrated with olanzapine for an additional week The rats were trained on a spatial memory task in an eight-arm radial maze before OA administration, and tested on the same task 18 h after the last olanzapine injection. After the behavioral test, the rats were killed for Nissl staining and terminal deoxynucleutidyl transferase-mediated biotinylated UTP nick end labeling staining. OA significantly induced spatial memory impairment, and caused pyramidal cell loss in the CAI and apoptotic cell death in the hippocampus. Olanzapine significantly attenuated OA-induced spatial memory impairment and the OA-induced neuropathological changes in the hippocampus. These findings suggest that olanzapine may have therapeutic effects in treatment of cognitive impairment and neuropathological changes of schizophrenia and other neurodegenerative diseases.

Chronic administration of quetiapine alleviates the anxiety-like behavioural changes induced by a neurotoxic regimen of dl-amphetamine in rats

We have demonstrated that the atypical antipsychotic drugs prevent cell death in PC12 cells induced by various cytotoxins and have protective effects on methamphetamine-induced neurotoxcity in rats. The present study was designed to examine the possible effects of chronic administration of quetiapine, an atypical antipsychotic drug, on the anxiety-like behavioural consequences of a neurotoxic regimen of dl-amphetamine. Rats were treated with quetiapine (10 mg/kg/day; i.p.) for 33 days. During days 15-19 of this period, the animals were given dl-amphetamine (20 mg/kg/day; s.c.) 1 h after the administration of quetiapine. The repeated administration of dl-amphetamine resulted in a decrease of tyrosine hydroxylase (TH) immunostaining in the caudate putamen, hyperthermia, and anxiety-like behavioural changes. The behavioural changes were indicated by a significant increase in the time spent in the light box in the light/dark box test, an increase in the ratios of ambulation distance inside the inner circle over the total ambulation distance and rearings inside the inner circle over the total rearings in the open field test, and an increase in the time spent in open arms in the elevated plus-maze test. Chronic administration of quetiapine significantly attenuated the dl-amphetamine-induced hyperthermia, and the anxiety-like behavioural changes in the light/dark box and in the open field tests. These results suggest that quetiapine can normalize the dl-amphetamine-induced anxiety-like behavioural changes, and might be helpful in the treatment for amphetamine-induced emotional changes.

RESISTANCE TO EXCESSIVE BODYWEIGHT GAIN IN RISPERIDONE-INJECTED RATS

1. The present study was carried out to explain the resistance of rats injected subcutaneously with risperidone, the atypical antipsychotic drug, for 21 consecutive days at 0.1 mg/kg per day (a dose equivalent to the one used for patients) to result in an excessive bodyweight despite the increase in diet-uptake in rats against risperidone-induced decrease in body temperature. 2. Rectal temperature measurements were made in 8-week-old male Sprague-Dawley rats maintained under standard laboratory conditions using a 12 h daylight cycle. A s.c. injection of risperidone (0.05 mg/kg) produced hypothermia in rats, which was observed during the daily injection for 21 consecutive days. 3. Sera, white and brown adipose tissues, skeletal muscle and liver were extracted from 8-week-old male Sprague-Dawley rats injected subcutaneously with risperidone (0.01 or 0.1 mg/kg per day) or a vehicle for 21 consecutive days. Serum levels of lipids, ketones and thyroid hormone were measured. The mRNA expression levels in these tissues and organs of the genes encoding the substances involved in heat production and/or lipid metabolism were investigated by using quantitative real-time polymerase chain reaction amplification. 4. Serum nonesterified fatty acid levels in risperidone 0.1 mg/kg per day s.c. injected rats were significantly lower than those in vehicle-injected ones. Serum beta-hydroxybutyrate levels in risperidone-injected rats tended to decrease compared with those in vehicle-injected ones. The serum level of neither triiodothyronine nor thyroxine was affected by risperidone s.c. injection at the doses examined, although their values were within normal limits. 5. Risperidone injection (0.1 mg/kg per day) for 21 consecutive days upregulated mRNA expressions in white adipose tissue of uncoupling protein 3 which dissipates energy as heat; peroxisome proliferator-activated receptor (PPAR) gamma coactivator 1alpha which activates mitochondrial biogenesis to expand the oxidative machinery; and PPARalpha which is necessary for the fat-depletion of adipocytes for thermogenesis. The mRNA of lipogenic enzymes (acetyl-CoA carboxylase alpha, fatty-acid synthase and glycerol-3-phosphate acyltransferase), hormone sensitive lipase and beta1-adrenoceptor were also enhanced in white adipose tissue by the injection of 0.1 mg/kg per day risperidone. 6. These findings suggest that the materials for heat generation in white adipose tissue would be readily supplied, which in turn would reduce a storage of lipids in white adipose tissue resulting in the lower rate of bodyweight gain of rats.

Post-stress changes in BDNF and Bcl-2 immunoreactivities in hippocampal neurons: effect of chronic administration of olanzapine

In the present study, we used a repeated restraint stress animal model to observe the changes in the expression of brain-derived neurotrophic factor (BDNF) and B cell lymphoma protein-2 (Bcl-2) in hippocampal neurons of rats, monitored the time course of the expression over 3 weeks post-stress period, and examined the effects of the chronic administration of olanzapine on the time course. Olanzapine is an atypical antipsychotic drug that has been shown to be neuroprotective in previous in vitro studies. We found: (1) the repeated restraint stress decreases the levels of expression of BDNF and Bcl-2 in hippocampal neurons; (2) the stress-induced decreases spontaneously recover to their pre-stress levels in 3 weeks after the last stress exposure; (3) administration of olanzapine for 1 week returns the expression of Bcl-2 to its pre-stress level, and the administration for 3 weeks causes an excessive expression of BDNF in hippocampal neurons. In the context of the lower levels of BDNF and Bcl-2, and structural brain abnormalities observed in patients with schizophrenia, our findings suggest that BDNF and Bcl-2 may be involved in the pathophysiology of schizophrenia and in the therapeutic action of atypical antipsychotic drugs.