Antioxidant properties of clozapine and related neuroleptics

Hematological and neurological impact studies on the exposure to naturally occurring radioactive materials

Naturally Occurring Radioactive Materials (NORM) contribute to everyone's natural background radiation dose. The technologically advanced activities of the gas and oil sectors produce considerable amounts of radioactive materials as industrial by-products or waste products. The goal of the current study is to estimate the danger of long-term liability to Technologically Enhanced Naturally Occurring Radioactive Materials (TE-NORM) on blood indices, neurotransmitters, oxidative stress markers, and β-amyloid in the cerebral cortex of rats' brains. Twenty adult male albino rats were divided into two equal groups (n = 10): control and irradiated. Irradiated rats were exposed to a total dose of 0.016 Gy of TE-NORM as a whole-body chronic exposure over a period of two months. It should be ''The results showed no significant changes in RBC count, Hb concentration, hematocrit percentage (HCT%), and Mean Corpuscular Hemoglobin Concentration (MCHC). However, there was a significant increase in the Mean Corpuscular Volume of RBCs (MCV) and a significant decrease in cell distribution width (RDW%) compared to the control. Alteration in neurotransmitters is noticeable by a significant increase in glutamic acid and significant decreases in serotonin and dopamine. Increased lipid peroxidation, decreased glutathione content, superoxide dismutase, catalase, and glutathione peroxidase activities indicating oxidative stress were accompanied by increased β-amyloid in the cerebral cortex of rats' brains. The findings of the present study showed that chronic radiation liability has some harmful effects, that may predict the risks of future health problems in occupational radiation exposure in the oil industries. Therefore, the control of exposure and application of sample dosimetry is recommended for health and safety.

CLEAR - clozapine in early psychosis: study protocol for a multi-centre, randomised controlled trial of clozapine vs other antipsychotics for young people with treatment resistant schizophrenia in real world settings

BACKGROUND

Clozapine is an antipsychotic drug with unique efficacy, and it is the only recommended treatment for treatment-resistant schizophrenia (TRS: failure to respond to at least two different antipsychotics). However, clozapine is also associated with a range of adverse effects which restrict its use, including blood dyscrasias, for which haematological monitoring is required. As treatment resistance is recognised earlier in the illness, the question of whether clozapine should be prescribed in children and young people is increasingly important. However, most research to date has been in older, chronic patients, and evidence regarding the efficacy and safety of clozapine in people under age 25 is lacking. The CLEAR (CLozapine in EARly psychosis) trial will assess whether clozapine is more effective than treatment as usual (TAU), at the level of clinical symptoms, patient rated outcomes, quality of life and cost-effectiveness in people below 25 years of age. Additionally, a nested biomarker study will investigate the mechanisms of action of clozapine compared to TAU.

METHODS AND DESIGN

This is the protocol of a multi-centre, open label, blind-rated, randomised controlled effectiveness trial of clozapine vs TAU (any other oral antipsychotic monotherapy licenced in the British National Formulary) for 12 weeks in 260 children and young people with TRS (12-24 years old).

AIM AND OBJECTIVES

The primary outcome is the change in blind-rated Positive and Negative Syndrome Scale scores at 12 weeks from baseline. Secondary outcomes include blind-rated Clinical Global Impression, patient-rated outcomes, quality of life, adverse effects, and treatment adherence. Patients will be followed up for 12 months and will be invited to give consent for longer term follow-up using clinical records and potential re-contact for further research. For mechanism of action, change in brain magnetic resonance imaging (MRI) biomarkers and peripheral inflammatory markers will be measured over 12 weeks.

DISCUSSION

The CLEAR trial will contribute knowledge on clozapine effectiveness, safety and cost-effectiveness compared to standard antipsychotics in young people with TRS, and the results may guide future clinical treatment recommendation for early psychosis.

TRIAL REGISTRATION

ISRCTN Number: 37176025, IRAS Number: 1004947.

TRIAL STATUS

In set-up. Protocol version 4.0 01/08/23. Current up to date protocol available here: https://fundingawards.nihr.ac.uk/award/NIHR131175# /.

Clozapine suppresses NADPH oxidase activation, counteracts cytosolic H2O2, and triggers early onset mitochondrial dysfunction during adipogenesis of human liposarcoma SW872 cells

Long-term treatment of schizophrenia with clozapine (CLZ), an atypical antipsychotic drug, is associated with an increased incidence of metabolic disorders mediated by poorly understood mechanisms. We herein report that CLZ, while slowing down the morphological changes and lipid accumulation occurring during SW872 cell adipogenesis, also causes an early (day 3) inhibition of the expression/nuclear translocation of CAAT/enhancer-binding protein β and peroxisome proliferator-activated receptor γ. Under the same conditions, CLZ blunts NADPH oxidase-derived reactive oxygen species (ROS) by a dual mechanism involving enzyme inhibition and ROS scavenging. These effects were accompanied by hampered activation of the nuclear factor (erythroid-derived2)-like 2 (Nrf2)-dependent antioxidant responses compared to controls, and by an aggravated formation of mitochondrial superoxide. CLZ failed to exert ROS scavenging activities in the mitochondrial compartment but appeared to actively scavenge cytosolic H2O2 derived from mitochondrial superoxide. The early formation of mitochondrial ROS promoted by CLZ was also associated with signs of mitochondrial dysfunction. Some of the above findings were recapitulated using mouse embryonic fibroblasts. We conclude that the NADPH oxidase inhibitory and cytosolic ROS scavenging activities of CLZ slow down SW872 cell adipogenesis and suppress their Nrf2 activation, an event apparently connected with increased mitochondrial ROS formation, which is associated with insulin resistance and metabolic syndrome. Thus, the cellular events characterised herein may help to shed light on the more detailed molecular mechanisms explaining some of the adverse metabolic effects of CLZ.

Human Hemoglobin and Antipsychotics Clozapine, Ziprasidone and Sertindole: Friends or Foes?

Packed with hemoglobin, an essential protein for oxygen transport, human erythrocytes are a suitable model system for testing the pleiotropic effects of lipophilic drugs. Our study investigated the interaction between antipsychotic drugs clozapine, ziprasidone, sertindole, and human hemoglobin under simulated physiological conditions. Analysis of protein fluorescence quenching at different temperatures and data obtained from the van't Hoff diagram and molecular docking indicate that the interactions are static and that the tetrameric human hemoglobin has one binding site for all drugs in the central cavity near αβ interfaces and is dominantly mediated through hydrophobic forces. The association constants were lower-moderate strength (~10⁴ M^-1), the highest observed for clozapine (2.2 × 10⁴ M^-1 at 25 °C). The clozapine binding showed "friendly" effects: increased α-helical content, a higher melting point, and protein protection from free radical-mediated oxidation. On the other hand, bound ziprasidone and sertindole had a slightly pro-oxidative effect, increasing ferrihemoglobin content, a possible "foe". Since the interaction of proteins with drugs plays a vital role in their pharmacokinetic and pharmacodynamic properties, the physiological significance of the obtained findings is briefly discussed.

Simultaneous Quantification of Antioxidants Paraxanthine and Caffeine in Human Saliva by Electrochemical Sensing for CYP1A2 Phenotyping

The enzyme CYP1A2 is responsible for the metabolism of numerous antioxidants in the body, including caffeine, which is transformed into paraxanthine, its main primary metabolite. Both molecules are known for their antioxidant and pro-oxidant characteristics, and the paraxanthine-to-caffeine molar ratio is a widely accepted metric for CYP1A2 phenotyping, to optimize dose–response effects in individual patients. We developed a simple, cheap and fast electrochemical based method for the simultaneous quantification of paraxanthine and caffeine in human saliva, by differential pulse voltammetry, using an anodically pretreated glassy carbon electrode. Cyclic voltammetry experiments revealed for the first time that the oxidation of paraxanthine is diffusion controlled with an irreversible peak at ca. +1.24 V (vs. Ag/AgCl) in a 0.1 M H₂SO₄ solution, and that the mechanism occurs via the transfer of two electrons and two protons. The simultaneous quantification of paraxanthine and caffeine was demonstrated in 0.1 M H₂SO₄ and spiked human saliva samples. In the latter case, limits of detection of 2.89 μM for paraxanthine and 5.80 μM for caffeine were obtained, respectively. The sensor is reliable, providing a relative standard deviation within 7% (n = 6). Potential applicability of the sensing platform was demonstrated by running a small scale trial on five healthy volunteers, with simultaneous quantification by differential pulse voltammetry (DPV) of paraxanthine and caffeine in saliva samples collected at 1, 3 and 6 h postdose administration. The results were validated by ultra-high pressure liquid chromatography and shown to have a high correlation factor (r = 0.994).

Antioxidant Potential of Psychotropic Drugs: From Clinical Evidence to In Vitro and In Vivo Assessment and toward a New Challenge for in Silico Molecular Design

Due to high oxygen consumption, the brain is particularly vulnerable to oxidative stress, which is considered an important element in the etiopathogenesis of several mental disorders, including schizophrenia, depression and dependencies. Despite the fact that it is not established yet whether oxidative stress is a cause or a consequence of clinic manifestations, the intake of antioxidant supplements in combination with the psychotropic therapy constitutes a valuable solution in patients' treatment. Anyway, some drugs possess antioxidant capacity themselves and this aspect is discussed in this review, focusing on antipsychotics and antidepressants. In the context of a collection of clinical observations, in vitro and in vivo results are critically reported, often highlighting controversial aspects. Finally, a new challenge is discussed, i.e., the possibility of assessing in silico the antioxidant potential of these drugs, exploiting computational chemistry methodologies and machine learning. Despite the physiological environment being incredibly complex and the detection of meaningful oxidative stress biomarkers being all but an easy task, a rigorous and systematic analysis of the structural and reactivity properties of antioxidant drugs seems to be a promising route to better interpret therapeutic outcomes and provide elements for the rational design of novel drugs.

Pathomechanisms of Blood-Brain Barrier Disruption in ALS

The blood-brain barrier (BBB) and the blood-spinal cord barrier (BSCB) are responsible for controlling the microenvironment within neural tissues in humans. These barriers are fundamental to all neurological processes as they provide the extreme nutritional demands of neural tissue, remove wastes, and maintain immune privileged status. Being a semipermeable membrane, both the BBB and BSCB allow the diffusion of certain molecules, whilst restricting others. In amyotrophic lateral sclerosis (ALS) and other neurodegenerative diseases, these barriers become hyperpermeable, allowing a wider variety of molecules to pass through leading to more severe and more rapidly progressing disease. The intention of this review is to discuss evidence that BBB hyperpermeability is potentially a disease driving feature in ALS and other neurodegenerative diseases. The various biochemical, physiological, and genomic factors that can influence BBB permeability in ALS and other neurodegenerative diseases are also discussed, in addition to novel therapeutic strategies centred upon the BBB.

ErbB signaling antagonist ameliorates behavioral deficit induced by phencyclidine (PCP) in mice, without affecting metabolic syndrome markers

Schizophrenia is a severe syndrome that affects about 1% of the world population. Since the mid-1950s, antipsychotics have been used to treat schizophrenia with preference for treating positive symptoms; however, their tolerance level is low, there are numerous side effects, and only some patients respond to the treatment. Antipsychotic medications that are more effective, better tolerated, and with fewer adverse effects are urgently needed. Given the accumulating evidence of the role filled by the ErbB signaling network in the biology of the dopamine, GABA, and glutamate systems, and in the etiology of schizophrenia, we hypothesized that the ErbB network is a candidate for development of a novel agent through which various symptoms of schizophrenia and other psychiatric disorders might be treated. Herein, we studied, in mice, the capability of blocking the ErbB signaling, in comparison with the atypical antipsychotic drug clozapine, to counter schizophrenia-like behavior induced by acute and sub-chronic phencyclidine (PCP), and determined whether inhibition of the ErbB networks induced weight gain and affected social and exploratory behavior, and metabolic syndrome markers. We demonstrated that administration of the pan-ErbB inhibitor JNJ28871063 (JNJ) reduced the level of activity in the open field induced by an acute injection of PCP. Moreover, the ability of JNJ to attenuate the effect of PCP is as effective as clozapine. In addition and like clozapine, JNJ normalized social behavior impairment induced by sub-chronic PCP and stress. Adult JNJ-treated mice displayed normal sociability and exploratory behavior, and their serum cholesterol, LDL, and HDL levels were lower than in the saline-treated mice. Sub-chronic treatment did not affect weight gain, glucose levels, and the activity of hepatic enzymes catalase and SOD. These data suggest that treatment with JNJ attenuates abnormal behaviors induced by PCP, and has similar effects as the antipsychotic drug clozapine, with no adverse effects. Thus, the ErbB signaling can serve as a new starting point for non-dopaminergic-based drug development of schizophrenia.

Antioxidant properties of atypical antipsychotic drugs used in the treatment of schizophrenia

The aim of this study was to compare the antioxidant activities of six atypical antipsychotic drugs: clozapine (CLZ), quetiapine, olanzapine (OLA), risperidone, ziprasidone, aripiprazole (ARI), as well as a typical antipsychotic drug, haloperidol. Several tests of antioxidant activity were used: protection of thiol groups against oxidation by peroxynitrite (PN) and 3-morpholinosydnonimine (SIN-1, generator of PN), oxidation of dihydrorhodamine 123 by PN, SIN-1 and hypochlorite (NaOCl), bleaching of fluorescein fluorescence by PN, 2,2'-azobis(2-amidinopropane) dihydrochloride (AAPH, generator of peroxyl radicals) and NaOCl, radical-scavenging activity with respect to 2,2'-azinobis(3-ethylbenzthiazoline-6-sulfonic acid) radical, 2,2-diphenyl-1-picrylhydrazyl free radical and the Ferric Reducing Antioxidant Potential. In most of the tests, OLA showed the highest antioxidant activity, followed by CLZ and in some cases ARI, other compounds being much less active or not active. OLA and CLZ exerted limited toxicity on mouse neuroblastoma Neuro-2A (N2A) cells and protected the cells against the toxic action of SIN-1, AAPH and NaOCl in the physiologically relevant concentration range of these oxidants. Both drugs reduced the PN-induced nitration of intracellular proteins. Given that schizophrenia is associated with oxidative and nitrosative stress, the direct antioxidant activity OLA and CLZ may contribute to the therapeutic action of these compounds.

Redox modulation of adipocyte differentiation: hypothesis of "Redox Chain" and novel insights into intervention of adipogenesis and obesity

In view of the global prevalence of obesity and obesity-associated disorders, it is important to clearly understand how adipose tissue forms. Accumulating data from various laboratories implicate that redox status is closely associated with energy metabolism. Thus, biochemical regulation of the redox system may be an attractive alternative for the treatment of obesity-related disorders. In this work, we will review the current data detailing the role of the redox system in adipocyte differentiation, as well as identifying areas for further research. The redox system affects adipogenic differentiation in an extensive way. We propose that there is a complex and interactive "redox chain," consisting of a "ROS-generating enzyme chain," "combined antioxidant chain," and "transcription factor chain," which contributes to fine-tune the regulation of ROS level and subsequent biological consequences. The roles of the redox system in adipocyte differentiation are paradoxical. The redox system exerts a "tridimensional" mechanism in the regulation of adipocyte differentiation, including transcriptional, epigenetic, and posttranslational modulations. We suggest that redoxomic techniques should be extensively applied to understand the biological effects of redox alterations in a more integrated way. A stable and standardized "redox index" is urgently needed for the evaluation of the general redox status. Therefore, more effort should be made to establish and maintain a general redox balance rather than to conduct simple prooxidant or antioxidant interventions, which have comprehensive implications.

Measuring antioxidant and prooxidant capacity using the Crocin Bleaching Assay (CBA)

The Crocin Bleaching Assay (CBA) appears in literature as an in vitro method for measuring antioxidant and prooxidant capacity of model dietary antioxidants, food formulations, pharmaceuticals, and biological samples. The assay is based on simple competitive reactions between a colored probe, crocin, and the test compounds/constituents for scavenging peroxyl radicals generated after thermolysis of a water-soluble azo-initiator. So far, several researchers in the fields of food chemistry, nutrition and clinical biochemistry have sporadically addressed critical views about advantages, limitations and potential field of CBA application. This chapter presents step-by-step critical aspects of CBA in order to assist standardization of its performance. Detailed procedures for calculation of two attributes of peroxyl radical scavenging reactions, the relative rate constant and "total antioxidant capacity", are also presented.

A study of antioxidant activity in patients with schizophrenia taking atypical antipsychotics

INTRODUCTION

Atypical antipsychotics have significantly improved the quality of life for schizophrenic patients. Despite their beneficial effects, these antipsychotics induce weight gain, diabetes, and dyslipidemia. The aims of this study were to investigate the antioxidative activity of paraoxonase and assess lipid profile as a cardiovascular risk factor in patients with schizophrenia under long-term clozapine or risperidone treatment.

METHODS

The study included 66 patients with schizophrenia under clozapine or risperidone treatment and 19 healthy control subjects. Serum paraoxonase activities against paraoxon (PON(PO)), phenylacetate (PON(PA)), dihydrocoumarin (PON(DHC)), serum Trolox equivalent antioxidant activity (TEAC), antioxidant gap (GAP), and lipid profile were determined.

RESULTS

PON(DHC) activity was reduced in both antipsychotic drug-treated groups (clozapine 43.46 ± 1.06 U/ml, p < 0.001; risperidone 50.57 ± 1.54 U/ml, p < 0.01; control 52.27 ± 1.34 U/ml). A similar pattern was observed for the PON(DHC)/HDL-cholesterol (HDLC) ratio. On the contrary, PON(PO) and PON(PA) were increased in the treated group, but the corresponding paraoxonase/HDLC ratios were not significantly different from controls, except for PON/HDLC in the clozapine group. TEAC and GAP were only decreased in the clozapine-treated group.

CONCLUSIONS

In patients with schizophrenia, clozapine or risperidone treatment had different effects on various paraoxonase activities. The results of the present study suggest that patients with schizophrenia might be at increased risk for metabolic and cardiovascular disease related to reduced PON(DHC), TEAC, and GAP.

Lipokines and oxysterols: novel adipose-derived lipid hormones linking adipose dysfunction and insulin resistance

The expansion of adipose tissue (AT) is, by definition, a hallmark of obesity. However, not all increases in fat mass are associated with pathophysiological cues. Indeed, whereas a "healthy" fat mass accrual, mainly in the subcutaneous depots, preserves metabolic homeostasis, explaining the occurrence of the metabolically healthy obese phenotype, "unhealthy" AT expansion is importantly associated with insulin resistance/type 2 diabetes and the metabolic syndrome. The development of a dysfunctional adipose organ may find mechanistic explanation in a reduced ability to recruit new and functional (pre)adipocytes from undifferentiated precursor cells. Such a failure of the adipogenic process underlies the "AT expandability" paradigm. The inability of AT to expand further to store excess nutrients, rather than obesity per se, induces a diabetogenic milieu by promoting the overflow and the ectopic deposition of fatty acids in insulin-dependent organs (i.e., lipotoxicity), the secretion of various metabolically detrimental adipose-derived hormones (i.e., adipokines and lipokines), and the occurrence of local and systemic inflammation and oxidative stress. Hitherto, fatty acids (i.e., lipokines) and the oxidation by-products of cholesterol and polyunsaturated fatty acids, such as nonenzymatic oxysterols and reactive aldehyde species, respectively, emerge as key modulators of (pre)adipocyte signaling through Wnt/β-catenin and MAPK pathways and potential regulators of glucose homeostasis. These and other mechanistic insights linking adipose dysfunction, oxidative stress, and impairment of glucose homeostasis are discussed in this review article, which focuses on adipose peroxidation as a potential instigator of, and a putative therapeutic target for, obesity-associated metabolic dysfunctions.

The effects of ziprasidone, clozapine and haloperidol on lipid peroxidation in human plasma (in vitro): comparison

Oxidative injury in schizophrenia can be caused by the disease itself and probably by antipsychotics treatment. The aim of the study was to establish whether there is a difference between ziprasidone, clozapine and haloperidol effect on lipid peroxidation in human plasma, measured by the level of thiobarbituric acid reactive substances (TBARS). The samples of plasma from healthy subjects were incubated with the drugs (1 and 24 h) and compared with control samples. The levels of TBARS were measured spectrophotometrically, according to the Rice-Evans method. The multifactorial variance analysis ANOVA II test showed that the differences in TBARS levels significantly depended on the studied drugs (ziprasidone 40 ng/ml, haloperidol 4 ng/ml and clozapine 350 ng/ml) (F = 3.248 p = 0.047) and (ziprasidone 139 ng/ml, haloperidol 20 ng/ml and clozapine 420 ng/ml) (F = 2.248, p = 2.9 × 10(-5)). Statistically increased levels of TBARS after 24 h incubation of plasma with ziprasidone 139 ng/ml and haloperidol 20 ng/ml (p < 0.001, p < 0.05 respectively) in comparison with control samples were observed. Clozapine did not significantly (p > 0.05) increase TBARS level in plasma in comparison with control samples. The results obtained in the study showed that ziprasidone and haloperidol contrary to clozapine induced a significant increase in plasma lipid peroxidation.

Oxidative stress and lipid peroxidation by-products at the crossroad between adipose organ dysregulation and obesity-linked insulin resistance

Obesity has been proposed as an energy balance disorder in which the expansion of adipose tissue (AT) leads to unfavorable health outcomes. Even though adiposity represents the most powerful driving force for the development of insulin resistance (IR) and type 2 diabetes, mounting evidence points to "adipose dysregulation", rather than fat mass accrual per se, as a key pathophysiological trigger of the obesity-linked metabolic complications. The dysfunctional fat, besides hypertrophic adipose cells and inflammatory cues, displays a reduced ability to form new adipocytes from the undifferentiated precursor cells (ie, the preadipocytes). The failure of adipogenesis poses a "diabetogenic" milieu either by promoting the ectopic overflow/deposition of lipids in non-adipose targets (lipotoxicity) or by inducing a dysregulated secretion of different adipose-derived hormones (ie, adipokines and lipokines). This novel and provocative paradigm ("expandability hypothesis") further extends current "adipocentric view" implicating a reduced adipogenic capacity as a missing link between "unhealthy" fat expansion and impairment of metabolic homeostasis. Hitherto, reactive oxygen species have been implicated in multiple forms of IR. However, the effects of stress on adipogenesis remain controversial. Compelling circumstantial data indicate that lipid peroxidation by-products (ie, oxysterols and 4-hydrononenal) may detrimentally affect adipose homeostasis partly by impairing (pre)adipocyte differentiation. In this scenario, it is tempting to speculate that a fine tuning of the adipose redox status may provide new mechanistic insights at the interface between fat dysregulation and development of metabolic dysfunctions. Yet, in humans, the molecular "signatures" of oxidative stress in the dysregulated fat as well as the pathophysiological effects of adipose (per)oxidation on glucose homeostasis remain poorly investigated. In this review we will summarize the potential mechanisms by which increased oxidative stress in fat may impair (pre)adipocyte differentiation and promote the adipose dysfunction. We will also attempt to highlight the conundrum with the adipose redox changes and the regulation of glucose homeostasis. Finally, we will briefly discuss the scientific rationale for proposing the adipose redox state as a potential target for novel therapeutic strategies to curb/prevent adiposity-linked insulin resistance.

Effects of antipsychotics and vitamin C on the formation of reactive oxygen species

There is evidence that reactive oxygen species (ROS) are involved in the pathophysiology of psychiatric disorders such as schizophrenia. Indirect biochemical alterations of ROS formation have been shown for patients treated with antipsychotics as well as for untreated patients. Only one study measured directly the ROS formation after treatment with antipsychotics by using electron spin resonance spectroscopy. The aim of the present examination was to demonstrate the effects of haloperidol, clozapine and olanzapine in concentrations of 18, 90 and 180 μg/mL on the formation of ROS in the whole blood of rats by using electron spin resonance spectroscopy after incubation for 30 min. To test the protective capacity of vitamin C we incubated the highest concentration of each drug with vitamin C (1 mM). Under all treatment conditions, olanzapine led to a significantly higher formation of ROS compared with control conditions, whereas in the cases of haloperidol and clozapine the two higher concentrations induced a significantly enhanced formation of ROS. Vitamin C reduced the ROS production of all drugs tested and for haloperidol and clozapine the level of significance was reached. Our study demonstrated that antipsychotics induce the formation of ROS in the whole blood of rats, which can be reduced by the application of vitamin C.

Antioxidant activity of newly synthesized 2,7-diazaphenothiazines

A series of 19 derivatives of 2,7-diazaphenothiazine was synthesized and evaluated for their antioxidant activity bearing in mind the structural similarity with "classical" phenothiazines several of which are considered powerful antioxidants. Among the new derivatives that inhibited in vitro Fe(2+)/ascorbate-induced lipid peroxidation of rat liver microsomal membranes, several exhibited significant antioxidant activity with IC(50 )values in the range of 64-125 microM. Although N-substitution led to a variable degree of antioxidant activity, the latter appears to correlate with the lipophilicity (expressed as clogP values) of the substituted derivatives. Reduced lipophilicity may also explain the relatively lower protection offered by these derivatives against lipid peroxidation when compared to their "classical" phenothiazine counterparts. Thus, modification of the phenothiazine structure by a substitution of two benzene rings with pyridine rings to form this new type of azaphenothiazines does not enhance antioxidant activity, although it retains it.

Behavioral and neurobiological changes in C57BL/6 mouse exposed to cuprizone: effects of antipsychotics

Recent human studies suggest a role for altered oligodendrocytes in the pathophysiology of schizophrenia. Our recent animal study has reported some schizophrenia-like behaviors in mice exposed to cuprizone (Xu et al., 2009), a copper chelator that has been shown to selectively damage the white matter. This study was to explore mechanisms underlying the behavioral changes in cuprizone-exposed mice and to examine effects of the antipsychotics haloperidol, clozapine and quetiapine on the changes in the mice. Mice given cuprizone for 14 days showed a deficit in the prepulse inhibition of acoustic startle response and higher dopamine in the prefrontal cortex (PFC), which changes were not seen in mice given cuprizone plus antipsychotics. Mice given cuprizone for 21 days showed lower spontaneous alternations in Y-maze, which was not seen in mice treated with cuprizone plus the antipsychotics. Mice given cuprizone for 28 days displayed less social interactions, which was not seen in mice given cuprizone plus clozapine/quetiapine, but was seen in mice given cuprizone plus haloperidol. Mice given cuprizone for 42 days showed myelin sheath loss and lower myelin basic protein in PFC, caudate putamen, and hippocampus. The white matter damage in PFC was attenuated in mice given cuprizone plus clozapine/haloperidol. But the white matter damage in caudate putamen and hippocampus was only attenuated by clozapine and quetiapine, not by haloperidol. These results help us to understand the behavioral changes and provide experimental evidence for the protective effects of antipsychotics on white matter damage in cuprizone-exposed mice.

Impact of haloperidol and quetiapine on the expression of genes encoding antioxidant enzymes in human neuroblastoma SH-SY5Y cells

Antipsychotics are known to alter antioxidant activities in vivo. Therefore, the aim of the present study was to examine in the human neuroblastoma SH-SY5Y cell line the impact of a typical (haloperidol) and an atypical (quetiapine) antipsychotic on the expression of genes encoding the key enzymes of the antioxidant metabolism (Cu, Zn superoxide dismutase; Mn superoxide dismutase; glutathione peroxidase; catalase) and enzymes of the glutathione metabolism (gamma-glutamyl cysteine synthetase, glutathione-S-transferase, gamma-glutamyltranspeptidase, glutathione reductase). The cells were incubated for 24h with 0.3, 3, 30 and 300microM haloperidol and quetiapine, respectively; mRNA levels were measured by polymerase chain reaction. In the present study, we observed mostly significant decreases of mRNA contents. With respect to the key pathways, we detected mainly effects on the mRNA levels of the hydrogen peroxide detoxifying enzymes. Among the enzymes of the glutathione metabolism, glutathione-S-transferase- and gamma-glutamyltranspeptidase-mRNA levels showed the most prominent effects. Taken together, our results demonstrate a significantly reduced expression of genes encoding for antioxidant enzymes after treatment with the antipsychotics, haloperidol and quetiapine.

Does treating schizophrenia reduce the chances of developing amyotrophic lateral sclerosis?

The development of amyotrophic lateral sclerosis (ALS) in the relatively common psychiatric disorder schizophrenia is very rare. This observation has been made by us and a number of other neuromuscular specialists at large ALS centers. We propose that the use of neuroleptics and some antidepressants, which are chronically prescribed to schizophrenics and which have neuroprotective properties and some of which promote neurogenesis, may confer protection against this deadly neurodegenerative disease ALS. Such an observation may have important implications towards the therapy and understanding the pathophysiology of this deadly neurodegenerative disease.

Beneficial effect of antioxidants in purified neurons derived from rat cortical culture

Brain cell suspensions obtained from cerebrum of fetal rats were cultured and after 5 days neurons were separated from the residual cells. These purified neurons, which were replated on the dish, started to die within 24 h in culture. Glutathione content of these neurons decreased rapidly to less than one-tenth of the initial level after 24 h. In the presence of alpha-tocopherol, a well-known antioxidant, the neurons survived for at least 3 days, though glutathione content remained very low. Butylated hydroxyanisol had similar effect, but ascorbic acid and uric acid had no or very little effect. Serotonin, which is assumed to have an antioxidant activity, kept the neurons alive for 3 days. These results suggest that neurons separated from the other types of cells cannot survive due to the oxidative stress, which may otherwise be neutralized by a mechanism involving glutathione, and that antioxidants including serotonin has a beneficial effect on these purified neurons.

Brain lipid composition in postnatal iron-induced motor behavior alterations following chronic neuroleptic administration in mice

Several studies have shown that deficient uptake or excessive break down of membrane phospholipids may be associated with neurodegenerative and psychiatric disorders. The purpose of the present study was to examine the effects of postnatal iron administration in lipid composition and behavior and whether or not the established effects may be altered by subchronic administration of the neuroleptic compounds, clozapine and haloperidol. In addition to motor activities such as locomotion, rearing and activity, a targeted lipidomics approach has been used to investigated the brains of eight groups of mice (four vehicle groups and four iron groups) containing six individuals in each group treated with vehicle, low dose clozapine, high dose clozapine and haloperidol. Lipids were extracted by the Folch method and analyzed using reversed-phase capillary liquid chromatography coupled on-line to electrospray ionization mass spectrometry (LC/ESI/MS). Identification of phosphatidylcholine (PC) and sphingomyelin (SM) molecular species was based on their retention time, m/z ratio, head group specific up-front fragmentation and analysis of the product ions produced upon fragmentation. A comparison between the Ve-groups and Fe-groups showed that levels of PC and SM molecular species and motor activities were significantly lower in Fe-Ve compared to Ve-Ve. The effects of neuroleptic treatment with and without iron supplementation were studied. In conclusion our results support the hypothesis that an association between psychiatric disorders and lipid and behavior abnormalities in the brain exists.

Therapeutic effects of xanthine oxidase inhibitors: renaissance half a century after the discovery of allopurinol

The prototypical xanthine oxidase (XO) inhibitor allopurinol, has been the cornerstone of the clinical management of gout and conditions associated with hyperuricemia for several decades. More recent data indicate that XO also plays an important role in various forms of ischemic and other types of tissue and vascular injuries, inflammatory diseases, and chronic heart failure. Allopurinol and its active metabolite oxypurinol showed considerable promise in the treatment of these conditions both in experimental animals and in small-scale human clinical trials. Although some of the beneficial effects of these compounds may be unrelated to the inhibition of the XO, the encouraging findings rekindled significant interest in the development of additional, novel series of XO inhibitors for various therapeutic indications. Here we present a critical overview of the effects of XO inhibitors in various pathophysiological conditions and also review the various emerging therapeutic strategies offered by this approach.

Bromocriptine and clozapine regulate dopamine 2 receptor gene expression in the mouse striatum

In a previous study, we showed that the psychoactive drug caffeine alters the expression of the dopamine 2 receptor (D2R) gene in vitro and in vivo. Here, we report that acute administration of antipsychotic and anti-parkinsonian drugs also regulate D2R gene expression in PC12 cells and in the mouse striatum. Treatment of PC12 cells with the atypical antipsychotic and specific 5-HT antagonist clozapine (60 microM) reduced D2R/luciferase reporter expression by 46% after 24 h. However, male and female mice treated with a clinical dose of clozapine (10 mg/kg) showed no changes in striatal D2R mRNA expression when assayed by quantitative RT-PCR. Treatment of PC12 cells with the specific D2R agonist anti-parkinsonian drug, bromocriptine mesylate (BCM; 5 microM) also resulted in decreased D2R/luciferase reporter activity (27%). In contrast to clozapine, a clinical dose of BCM (16 mg/kg) led to a 21% decrease and a 45% increase in striatal D2R mRNA expression in male and female mice, respectively, after 24 h. Coadministration of clozapine and BCM in PC12 cells resulted in a synergistic decrease in D2R/luciferase reporter expression (68%), and coadministration of these drugs in vivo led to decreases in striatal D2R mRNA expression in both male and female mice (45% and 22%, respectively). Collectively, these results indicate that clozapine, BCM, or a combination of these drugs have differential effects on dopamine receptor gene expression and might also affect striatal physiology in a sexually dimorphic manner.

Pro-oxidant activity of zuclopenthixol in vivo: differential effect of the drug on brain oxidative status of scopolamine-treated rats

Several clinical studies implicated oxidative stress in the pathophysiology of both psychosis and dementia. As dementia is commonly associated with psychosis, antipsychotic medications are of importance in the pharmacotherapy of dementia particularly as a number of antipsychotics were reported to demonstrate neuronal pro-oxidant and/or antioxidant properties. Impairment of learning and memory, as the most characteristic manifestation of dementia, could be induced in experimental animals by acute administration of scopolamine (SCO) with a resultant elevation in brain oxidative status. This study investigated the potential pro-oxidant and/or antioxidant activity of the antipsychotic drug zuclopenthixol acetate, as its effect on brain oxidative status has yet to be evaluated. A 2 x 3 between-subjects factorial design was used to investigate the simultaneous and interactive effects of zuclopenthixol (0.7 and 1.4 mg/kg i.p.) and SCO on rat brain malondialdehyde, glutathione, glutathione peroxidase and superoxide dismutase levels/activities. Results revealed a significant pro-oxidant effect for both zuclopenthixol and SCO alone conditions. In addition, combined treatment of zuclopenthixol and SCO was found to be significantly different compared to either treatment conditions with regard to their effect on different brain oxidative stress indices. Such findings may have valuable implications in the pharmacotherapy of both psychosis and dementia.

Interaction of two phenothiazine derivatives with phospholipid monolayers

This paper addresses the cooperative interaction of two phenothiazine drugs, viz. trifluoperazine (TFP) and chlorpromazine (CPZ), with phospholipid monolayers as the model membrane system. Surface pressure and surface potential isotherms were obtained for mixed Langmuir monolayers of either dipalmitoyl-phosphatidyl-choline (DPPC) or dipalmitoyl-phosphatidyl-glycerol (DPPG) co-spread with TFP or CPZ. The changes in monolayer behavior caused by incorporation of a few molar ratio of drug molecules were practically within the experimental dispersion for the zwitterionic DPPC, and therefore a more refined analysis will be required to probe the interactions in an unequivocal way. For the charged DPPG, on the other hand, the surface pressure and the dipole moment were significantly affected even for TFP or CPZ concentrations as low as 0.002 molar ratio. Overall, the effects from CPZ and TFP are similar, but small differences exist which are probably due to the different protonation properties of the two drugs. For both drugs, changes are more prominent at the liftoff of the surface pressure, i.e. at the gas-condensed phase transition, with the surface pressure and surface potential isotherms becoming more expanded with the drug incorporation. With DPPG/CPZ monolayers, in particular, an additional phase transition appears at higher CPZ concentrations, which resembles the effects from increasing the subphase temperature for a pure DPPG monolayer. The dipole moment for DPPG/CPZ and DPPG/TFP monolayers decreases with the drug concentration, which means that the effects from the charged drugs are not associated with changes in the double-layer potential. Otherwise, the effective dipole moment should increase with the drug concentration. The changes caused in surface pressure and dipole moment by small concentrations of TFP or CPZ can only be explained by some cooperative effect through which the contribution from DPPG molecules changes considerably, i.e. even DPPG molecules that are not neighbor to a CPZ or TFP molecule are also affected. Such changes may occur either through a significant reorientation of the DPPG molecules or to a change in their hydration state. We discuss the cooperativity semi-quantitatively by estimating the number of lipid molecules affected by the drug interaction. CPZ and TFP also affect the morphology of DPPG monolayers, which was confirmed with Brewster angle microscopy. The biological implications from the cooperative, non-specific interaction of CPZ and TFP with membranes are also commented upon.

Oxidative stress underlies the mechanism for Ca(2+)-induced permeability transition of mitochondria

Recent studies demonstrated that the generation of intracellular reactive oxygen species (ROS) was enhanced prior to the onset of mitochondrial membrane permeability transition (MPT), a critical step for the induction of DNA fragmentation and apoptosis. Although Ca2+ induces typical MPT that involves depolarization and swelling of mitochondria and finally releases cytochrome c into cytosol, the mechanism by which ROS induce MPT remains unclear. In the presence of inorganic phosphate, Ca2+ increased the oxygen consumption and ROS production by isolated mitochondria as determined by a chemiluminescence (CHL) method using L-012. Ca2+ increased the generation of H2O2 by some mechanism that was inhibited by cyclosporin A but not by superoxide dismutase (SOD) and trifluoperazine. Ca2+ decreased the content of free thiols in adenine nucleotide translocase (ANT) in mitochondrial membranes with concomitant increase in ROS generation. The presence of cyclosporin A, trifluoperazine, or SOD inhibited the Ca(2+)-induced increase of L-012 CHL and decrease in the free thiols of ANT. These results indicate that Ca2+ increases the generation of ROS which oxidize the free thiol groups in mitochondrial ANT, thereby inducing MPT to release cytochrome c.

Lack of chlorpromazine effect on skeletal muscle metabolism after ischemia and a short reperfusion period

The great resistance of muscle to ischemia was used to study blood flow-dependent phenomena produced by anesthetic drugs in this condition. A short reperfusion period was used in order to favor metabolic changes indicative of an effect of chlorpromazine (CPZ) on blood flow. Gracilis muscles of dogs were submitted to 5 h of ischemia and 30 min of reperfusion. CPZ-treated animals were injected I.V. (2 mg/kg) 10 min before the beginning of ischemia. Biopsies provided the material for tissue measurements. Lactate content and pH were determined in blood samples collected from a muscle efferent vein. In both the CPZ-treated and nontreated groups, ischemia induced a decline in muscle glycogen content, with a corresponding increase in muscle lactate and a decrease in mitochondrial respiratory control ratio. After 30 min of reperfusion, tissue levels of lactate did not attain preischemic values but showed a clear decline in the two experimental groups, evidencing the reversible state of the muscle. All other metabolic parameters remained unchanged. Mitochondrial respiratory control remained functional during ischemia and reperfusion. Blood pH displayed similar changes in both groups. There was no metabolic indication that the drug affected blood flow during early reperfusion and/or of a greater sensitivity of muscle endothelial cells to anesthetic drugs.

The increased activity of plasma manganese superoxide dismutase in tardive dyskinesia is unrelated to the Ala-9Val polymorphism

That tardive dyskinesia (TD) may have its origins in free-radical toxicity has stimulated investigations into one enzyme important in the control of oxidative free radicals: superoxide dismutase (SOD). The manganese-containing form of this enzyme (MnSOD) is the major superoxide scavenger in mitochondria; a weak association between a functional genetic polymorphism (Ala-9Val) in the mitochondrial targeting sequence (MTS) of this enzyme and TD has been reported in a Japanese population. We have undertaken to determine both the plasma activity of MnSOD and the association of the Ala-9Val polymorphism in a well-matched series of male Chinese schizophrenic patients with (n=42) and without (n=59) TD, and normal male controls (n=50). MnSOD activity was elevated in the TD subjects over those without TD (P<0.05) and normal controls (P<0.05), an effect that was independent of age, age at first antipsychotic treatment, drug dosage and duration of illness. A significant positive correlation between total AIMS score and MnSOD activity was also observed (P<0.0001). No significant reduction in the frequency of the Ala allele was observed in the TD group (0.14) below non-TD (0.18) or control subjects (0.17); nor was there any relationship between MnSOD activity and the polymorphism. There was no difference between the mean AIMS scores for the two genotypes (V/V and A/V) in the TD group. We conclude that while we have further evidence of a disturbance in the mechanisms regulating oxidative free radicals in TD, this effect is not under the control of the genetic polymorphism investigated here.

Comparison of the effects of clozapine, chlorpromazine, and haloperidol on membrane lateral heterogeneity

The interactions of three neuroleptic drugs, clozapine (CLZ), chlorpromazine (CPZ), and haloperidol (HPD) with phospholipids were compared using DSC and Langmuir balance. Main emphasis was on the drug-induced effects on the lateral organization of lipid mixtures of the saturated zwitterionic 1,2-dipalmitoyl-sn-glycero-3-phosphatidylcholine (DPPC) and the unsaturated acidic phosphatidylserine, brainPS. In multilamellar vesicles (MLV) phase separation was observed by DSC at X(PS)> or =0.05. All three drugs bound to these MLVs, abolishing the pretransition at X(drug)> or =0.03. The main transition temperature (T(m)) decreased almost linearly with increasing contents of the drugs, CLZ having the smallest effect. In distinction from the other two drugs, CLZ abolished the phase separation evident in the endotherms for DPPC/brainPS (X(PS)=0.05) MLVs. Compression isotherms of DPPC/brainPS/drug (X(PS)=X(drug)=0.05) monolayers revealed the neuroleptics to increase the average area/molecule, CLZ being the most effective. Penetration into brainPS monolayers showed strong interactions between the three drugs and this acidic phospholipid (in decreasing order CPZ>HPD>CLZ). Hydrophobic interactions demonstrated using neutral eggPC monolayers decreased in a different order, CLZ>CPZ>HPD. Fluorescence microscopy revealed domain morphology of DPPC/brainPS monolayers to be modulated by these drugs, increasing the gel-fluid domain boundary length in the phase coexistence region. To conclude, our data support the view that membrane-partitioning drugs could exert part of their effects by changing the lateral organization and thus also the functions of biomembranes.

Trifluoperazine induces domain formation in zwitterionic phosphatidylcholine but not in charged phosphatidylglycerol bilayers

The interaction of trifluoperazine with the zwitterionic lipids dipalmitoylphosphatidylcholine and dimyristoylphosphatidylcholine and with anionic dimyristoylphosphatidylglycerol was studied by means of microcalorimetry and fluorescence spectroscopy. Intercalation of drug molecules into the lipid bilayers was confirmed by the observed differential scanning calorimetry peak broadening and the decrease in chain-melting temperatures. For trifluoperazine:lipid mole ratios higher than 0.4 and 0.6 (for dipalmitoylphosphatidylcholine and dimyristoylphosphatidylcholine, respectively) the deconvolution of transition profiles into two Gaussian components was possible, which suggests phase separation in the studied mixtures. Deconvolution of the thermograms was not possible for any of the drug:dimyristoylphosphatidylglycerol mole ratios studied. To confirm the existence of phase separation in trifluoperazine-phosphatidylcholine mixtures fluorescence spectroscopy experiments were performed using Laurdan as a probe. From the generalised polarisation versus excitation wavelength dependences, recorded at different temperatures, we conclude that a phase separation occurs in the gel state of the studied trifluoperazine-phosphatidylcholine mixtures. We attribute the existence of domains in the bilayer to the dissimilar interactions of two protonation forms of trifluoperazine with phosphatidylcholine molecules. Structural defects present at domain boundaries could be related to the trifluoperazine induced increase of membrane permeability and fluidity. This may partially explain the mechanism of multidrug resistance modulation by trifluoperazine.

Glutathione depletion and the production of reactive oxygen species in isolated hepatocyte suspensions

Diethyl maleate (DEM) (5 mM) and ethyl methanesulfonate (EMS) (35 mM) treatments rapidly depleted cellular reduced glutathione (GSH) below detectable levels (1 nmol/10(6) cells), and induced lipid peroxidation and necrotic cell death in freshly isolated rat hepatocytes. In hepatocytes incubated with 2.5 mM DEM and 10 mM EMS, however, the complete depletion of cellular GSH observed was not sufficient to induce lipid peroxidation or cell death. Instead, DEM- and EMS-induced lipid peroxidation and cell death were dependent on increased reactive oxygen species (ROS) production as measured by increases in dichlorofluorescein fluorescence. The addition of antioxidants (vitamin E succinate and deferoxamine) prevented lipid peroxidation and cell death, suggesting that lipid peroxidation is involved in the sequence of events leading to necrotic cell death induced by DEM and EMS. To investigate the subcellular site of ROS generation, the cytochrome P450 inhibitor, SKF525A, was found to reduce EMS-induced lipid peroxidation but did not protect against the loss of cell viability, suggesting a mitochondrial origin for the toxic lipid peroxidation event. In agreement with this conclusion, mitochondrial electron transport inhibitors (rotenone, thenoyltrifluoroacetone and antimycin A) increased EMS-induced lipid peroxidation and cell death, while the mitochondrial uncoupler, carbonyl cyanide m-chlorophenylhydrazone, blocked EMS- and DEM-mediated ROS production and lipid peroxidation. Furthermore, EMS treatment resulted in the significant loss of mitochondrial alpha-tocopherol shortly after its addition, and this loss preceded losses in cellular alpha-tocopherol levels. Treatment of hepatocytes with cyclosporin A, a mitochondrial permeability transition inhibitor, oxypurinol, a xanthine oxidase inhibitor, or BAPTA-AM, a calcium chelator, provided no protection against EMS-induced cell death or lipid peroxidation. Our results indicate that DEM and EMS induce cell death by a similar mechanism, which is dependent on the induction of ROS production and lipid peroxidation, and mitochondria are the major source for this toxic ROS generation. Cellular GSH depletion in itself does not appear to be responsible for the large increases in ROS production and lipid peroxidation observed.

Could oxidative stress be a factor in neurodevelopmental disorders?

There is evidence of co-morbidity in the neurodevelopmental disorders and they display depletion of polyunsaturated fatty acids (PUFAs) in their plasma and red cell membranes. This suggests an abnormal fatty acid metabolism, which may affect cell signalling and synthesis of eicosanoids. This common feature in the neurodevelopmental disorders may be genetic in origin: however, oxidative stress may also contribute to decreased PUFAs found in these disorders.