Haloperidol Exposure Research Articles

Effects of gestational haloperidol exposure on mRNA expressions related to glutamate and GABA receptors in offspring

Antipsychotic treatment is vital for patients with schizophrenia even in the perinatal period, but the impact at the molecular biological level on offspring is unclear. The aim of the present study was to investigate the effects of intraperitoneal haloperidol injection to pregnant mice on glutamate and GABA receptors in the brain of offspring mice. Eight-week-old pregnant mice were treated with either intraperitoneal haloperidol or normal saline injection, and their offspring were defined as F1 mice. In addition, eight-week-old male mice were used as acute mice that were intraperitoneally injected with haloperidol or normal saline for 20 days. mRNA expression levels were measured by RT-qPCR. Western blotting was performed of the frontal lobes of F1 mice. In the hippocampi of F1 mice, Grik3 (p = 0.023) and Gabra3 (p = 0.004) mRNA expression levels were significantly higher in the haloperidol group than in the control group, whereas Gria2 (p < 0.001) and Grin2a (p < 0.001) mRNA expression levels were significantly lower in the haloperidol group than in the control group. Gria2 (p = 0.015), and Grik3 (p = 0.037), and Grin2a (p = 0.012) mRNA expression levels were significantly lower in the haloperidol group than in the control group in the frontal lobes of F1 mice. In the hippocampi of acute mice, Grik3 (p = 0.049) and Gabra3 (p = 0.007) mRNA expression levels were significantly decreased in the haloperidol group. Fetal exposure to haloperidol can affect glutamate and GABA receptors through mRNA expression changes in the brain of offspring.

Development and Evaluation of a Physiologically Based Pharmacokinetic Model for Predicting Haloperidol Exposure in Healthy and Disease Populations.

The physiologically based pharmacokinetic (PBPK) approach can be used to develop mathematical models for predicting the absorption, distribution, metabolism, and elimination (ADME) of administered drugs in virtual human populations. Haloperidol is a typical antipsychotic drug with a narrow therapeutic index and is commonly used in the management of several medical conditions, including psychotic disorders. Due to the large interindividual variability among patients taking haloperidol, it is very likely for them to experience either toxic or subtherapeutic effects. We intend to develop a haloperidol PBPK model for identifying the potential sources of pharmacokinetic (PK) variability after intravenous and oral administration by using the population-based simulator, PK-Sim. The model was initially developed and evaluated to predict the PK of haloperidol and its reduced metabolite in adult healthy population after intravenous and oral administration. After evaluating the developed PBPK model in healthy adults, it was used to predict haloperidol–rifampicin drug–drug interaction and was extended to tuberculosis patients. The model evaluation was performed using visual assessments, prediction error, and mean fold error of the ratio of the observed-to-predicted values of the PK parameters. The predicted PK values were in good agreement with the corresponding reported values. The effects of the pathophysiological changes and enzyme induction associated with tuberculosis and its treatment, respectively, on haloperidol PK, have been predicted precisely. For all clinical scenarios that were evaluated, the predicted values were within the acceptable two-fold error range.

Impact of Gestational Haloperidol Exposure on miR-137-3p and Nr3c1 mRNA Expression in Hippocampus of Offspring Mice.

Schizophrenia is a mental disorder caused by both environmental and genetic factors. Prenatal exposure to antipsychotics, an environmental factor for the fetal brain, induces apoptotic neurodegeneration and cognitive impairment of offspring similar to schizophrenia. The aim was to investigate molecular biological changes in the fetal hippocampus exposed to haloperidol (HAL) by RNA expression as a model of the disorder. HAL (1 mg/kg/d) was administered to pregnant mice. Upregulated and downregulated gene expressions in the hippocampus of offspring were studied with RNA-sequencing and validated with the qPCR method, and micro-RNA (miR) regulating mRNA expressional changes was predicted by in silico analysis. An in vitro experiment was used to identify the miRNA using a dual-luciferase assay. There were significant gene expressional changes (1370 upregulated and 1260 downregulated genes) in the HAL group compared with the control group on RNA-sequencing analysis (P &lt; .05 and q &lt; 0.05). Of them, the increase of Nr3c1 mRNA expression was successfully validated, and in silico analysis predicted that microRNA-137-3p (miR-137-3p) possibly regulates that gene's expression. The expression of miR-137-3p in the hippocampus of offspring was significantly decreased in the first generation, but it increased in the second generation. In vitro experiments with Neuro2a cells showed that miR-137-3p inversely regulated Nr3c1 mRNA expression, which was upregulated in the HAL group. These findings will be key for understanding the impact of the molecular biological effects of antipsychotics on the fetal brain.

Association Between Incident Delirium Treatment With Haloperidol and Mortality in Critically Ill Adults.

Haloperidol is commonly administered in the ICU to reduce the burden of delirium and its related symptoms despite no clear evidence showing haloperidol helps to resolve delirium or improve survival. We evaluated the association between haloperidol, when used to treat incident ICU delirium and its symptoms, and mortality. Post hoc cohort analysis of a randomized, double-blind, placebo-controlled, delirium prevention trial. Fourteen Dutch ICUs between July 2013 and December 2016. One-thousand four-hundred ninety-five critically ill adults free from delirium at ICU admission having an expected ICU stay greater than or equal to 2 days. Patients received preventive haloperidol or placebo for up to 28 days until delirium occurrence, death, or ICU discharge. If delirium occurred, treatment with open-label IV haloperidol 2 mg tid (up to 5 mg tid per delirium symptoms) was administered at clinician discretion. Patients were evaluated tid for delirium and coma for 28 days. Time-varying Cox hazards models were constructed for 28-day and 90-day mortality, controlling for study-arm, delirium and coma days, age, Acute Physiology and Chronic Health Evaluation-II score, sepsis, mechanical ventilation, and ICU length of stay. Among the 1,495 patients, 542 (36%) developed delirium within 28 days (median [interquartile range] with delirium 4 d [2-7 d]). A total of 477 of 542 (88%) received treatment haloperidol (2.1 mg [1.0-3.8 mg] daily) for 6 days (3-11 d). Each milligram of treatment haloperidol administered daily was associated with decreased mortality at 28 days (hazard ratio, 0.93; 95% CI, 0.91-0.95) and 90 days (hazard ratio, 0.97; 95% CI, 0.96-0.98). Treatment haloperidol administered later in the ICU course was less protective of death. Results were stable by prevention study-arm, predelirium haloperidol exposure, and haloperidol treatment protocol adherence. Treatment of incident delirium and its symptoms with haloperidol may be associated with a dose-dependent improvement in survival. Future randomized trials need to confirm these results.

Region-specific and dose-specific effects of chronic haloperidol exposure on [3H]-flumazenil and [3H]-Ro15-4513 GABAA receptor binding sites in the rat brain

Postmortem studies suggest that schizophrenia is associated with abnormal expression of specific GABAA receptor (GABAAR) α subunits, including α5GABAAR. Positron emission tomography (PET) measures of GABAAR availability in schizophrenia, however, have not revealed consistent alterations in vivo. Animal studies using the GABAAR agonist [3H]-muscimol provide evidence that antipsychotic drugs influence GABAAR availability, in a region-specific manner, suggesting a potential confounding effect of these drugs. No such data, however, are available for more recently developed subunit-selective GABAAR radioligands. To address this, we combined a rat model of clinically relevant antipsychotic drug exposure with quantitative receptor autoradiography. Haloperidol (0.5 and 2 mg/kg/day) or drug vehicle were administered continuously to adult male Sprague-Dawley rats via osmotic mini-pumps for 28 days. Quantitative receptor autoradiography was then performed postmortem using the GABAAR subunit-selective radioligand [3H]-Ro15-4513 and the non-subunit selective radioligand [3H]-flumazenil. Chronic haloperidol exposure increased [3H]-Ro15-4513 binding in the CA1 sub-field of the rat dorsal hippocampus (p<0.01; q<0.01; d=+1.3), which was not dose-dependent. [3H]-flumazenil binding also increased in most rat brain regions (p<0.05; main effect of treatment), irrespective of the haloperidol dose. These data confirm previous findings that chronic haloperidol exposure influences the specific binding of non-subtype selective GABAAR radioligands and is the first to demonstrate a potential effect of haloperidol on the binding of a α1/5GABAAR-selective radioligand. Although caution should be exerted when extrapolating results from animals to patients, our data support a view that exposure to antipsychotics may be a confounding factor in PET studies of GABAAR in the context of schizophrenia.

Haloperidol Interactions with the dop-3 Receptor in Caenorhabditis elegans.

Haloperidol is a typical antipsychotic drug commonly used to treat a broad range of psychiatric disorders related to dysregulations in the neurotransmitter dopamine (DA). DA modulates important physiologic functions and perturbations in Caenorhabditis elegans (C. elegans) and, its signaling have been associated with alterations in behavioral, molecular, and morphologic properties in C. elegans. Here, we evaluated the possible involvement of dopaminergic receptors in the onset of these alterations followed by haloperidol exposure. Haloperidol increased lifespan and decreased locomotor behavior (basal slowing response, BSR, and locomotion speed via forward speed) of the worms. Moreover, locomotion speed recovered to basal conditions upon haloperidol withdrawal. Haloperidol also decreased DA levels, but it did not alter neitherdop-1, dop-2, and dop-3 gene expression, nor CEP dopaminergic neurons' morphology. These effects are likely due to haloperidol's antagonism of the D2-type DA receptor, dop-3. Furthermore, this antagonism appears to affect mechanistic pathways involved in the modulation and signaling of neurotransmitters such as octopamine, acetylcholine, and GABA, which may underlie at least in part haloperidol's effects. These pathways are conserved in vertebrates and have been implicated in a range of disorders. Our novel findings demonstrate that the dop-3 receptor plays an important role in the effects of haloperidol.

Antipsychotic Behavioral Phenotypes in the Mouse Collaborative Cross Recombinant Inbred Inter-Crosses (RIX).

Schizophrenia is an idiopathic disorder that affects approximately 1% of the human population, and presents with persistent delusions, hallucinations, and disorganized behaviors. Antipsychotics are the standard pharmacological treatment for schizophrenia, but are frequently discontinued by patients due to inefficacy and/or side effects. Chronic treatment with the typical antipsychotic haloperidol causes tardive dyskinesia (TD), which manifests as involuntary and often irreversible orofacial movements in around 30% of patients. Mice treated with haloperidol develop many of the features of TD, including jaw tremors, tongue protrusions, and vacuous chewing movements (VCMs). In this study, we used genetically diverse Collaborative Cross (CC) recombinant inbred inter-cross (RIX) mice to elucidate the genetic basis of antipsychotic-induced adverse drug reactions (ADRs). We performed a battery of behavioral tests in 840 mice from 73 RIX lines (derived from 62 CC strains) treated with haloperidol or placebo in order to monitor the development of ADRs. We used linear mixed models to test for strain and treatment effects. We observed highly significant strain effects for almost all behavioral measurements investigated (P < 0.001). Further, we observed strong strain-by-treatment interactions for most phenotypes, particularly for changes in distance traveled, vertical activity, and extrapyramidal symptoms (EPS). Estimates of overall heritability ranged from 0.21 (change in body weight) to 0.4 (VCMs and change in distance traveled) while the portion attributable to the interactions of treatment and strain ranged from 0.01 (for change in body weight) to 0.15 (for change in EPS). Interestingly, close to 30% of RIX mice exhibited VCMs, a sensitivity to haloperidol exposure, approximately similar to the rate of TD in humans chronically exposed to haloperidol. Understanding the genetic basis for the susceptibility to antipsychotic ADRs may be possible in mouse, and extrapolation to humans could lead to safer therapeutic approaches for schizophrenia.

O11.3. SYNAPTIC MARKER PROTEIN SV2A IS REDUCED IN SCHIZOPHRENIA IN VIVO AND UNAFFECTED BY ANTIPSYCHOTICS IN RATS

BackgroundThe synaptic dysfunction hypothesis of schizophrenia is supported by multiple lines of evidence. However, in vivo evidence is lacking. Moreover, it is not known if antipsychotics alter synaptic protein levels. We addressed this in a combined clinical study using [11C]UCB-J, a positron emission tomography (PET) radioligand specific for synaptic vesicle glycoprotein 2A (SV2A), and rodent study of clinically relevant antipsychotic drug exposure.MethodsWe scanned 18 subjects with schizophrenia (SCZ) and 18 healthy volunteers (HV) with [11C]UCB-J PET and T1-weighted MRI, estimating grey matter volumes of distribution (VT) and corrected grey matter volumes (GMV) for the frontal cortex (FC), anterior cingulate cortex (ACC) and hippocampus. In addition, we estimated the [11C]UCB-J distribution volume ratio (DVR) in these regions, using the centrum semiovale (CS) as a pseudoreference region. We collected clinical data including PANSS score, chlorpromazine-equivalent antipsychotic dose (CPZ) and duration of illness (DOI). In parallel, we investigated the effects of olanzapine and haloperidol administration on SV2A levels in the Sprague-Dawley rat frontal cortex using western blotting, [3H]UCB-J autoradiography and immunostaining with confocal microscopy. We used two-way analysis of variance (ANOVA) to test effects of group, ROI and group-by-ROI interaction on VT and DVR. We used planned post hoc t-tests to test group effects at each ROI, with false discovery-rate adjustment for multiple comparisons. We used two-way ANOVA with Bonferroni’s post-hoc test to analyse autoradiography and SV2A immunostaining data, and the Kruskal-Wallis test, with alpha=0.05, to analyse western blot data.ResultsClinical study: We found significant group-by-region interaction (F2, 68=7.472, p=0.001), group (F1, 34=6.170, p=0.02) and ROI (F2, 68=426.0, p<0.0001) effects on VT, with significant reductions in mean [SEM] VT of large effect size in the SCZ group in the FC (SCZ=16.93 [0.80]; HV=19.50 [0.64]; t=2.51, df=34.0, p=0.03, Cohen’s d=0.8) and ACC (SCZ=19.55 [0.75]; HV=22.49 [0.72]; t=2.83, df=34.0, p=0.02, Cohen’s d=0.9), but not in the hippocampus (SCZ=14.09 [0.59]; HV=15.44 [0.50]; t=1.75, df=34.0, p=0.09, Cohen’s d=0.6). Furthermore, we found significant group-by-region interaction (F2, 68=7.97, p=0.0008), group (F1, 34=8.1, p=0.007) and ROI (F2, 68=510.9, p<0.0001) effects on DVR, with significant reductions of large effect size in the FC (SCZ=2.93 [0.17]; HV=3.48 [0.09]; t=2.89, df=34.0, p=0.01, Cohen’s d=1.0), ACC (SCZ=3.39 [0.17]; HV=3.99 [0.09]; t=3.05, df=34.0, p=0.01, Cohen’s d=1.0) and, additionally, hippocampus (SCZ=2.40 [0.12]; HV=2.74 [0.07]; t=2.32, df=34.0, p=0.03, Cohen’s d=0.8). There were no significant relationships (p>0.05) between VT and GMV, PANSS score, DOI and CPZ.Preclinical study: Chronic olanzapine or haloperidol exposure did not significantly affect total SV2A immunostaining intensity (p=0.97 and p=0.71 respectively) in the rat frontal cortex as compared to vehicle-exposed controls. Moreover, chronic haloperidol exposure did not significantly affect [3H]UCB-J specific binding (p=0.27) or SV2A protein levels (relative to GAPDH, p=0.71).DiscussionThese findings provide evidence for the first time that presynaptic marker protein levels are reduced in schizophrenia in vivo and that antipsychotic drug exposure is unlikely to account for this, consistent with the synaptic dysfunction hypothesis.

T209. EFFECTS OF CHRONIC HALOPERIDOL EXPOSURE ON [3H]RO15-4513 AND [3H]FLUMAZENIL GABA-A RECEPTOR BINDING SITES

BackgroundPost-mortem studies in schizophrenia (SZ) have reported abnormalities in the GABAergic system, more specifically, on αGABA-A receptors (αGABA-A R) (Benes, Kwok, Vincent, & Todtenkopf, 1998; Beneyto, Abbott, Hashimoto, & Lewis, 2011). Consistently, animal models of SZ have also reported changes in these receptor subtypes (Lodge, Behrens, & Grace, 2009; Richetto, Calabrese, Riva, & Meyer, 2014). Preclinical work in the methylazoxymethanol acetate (MAM) animal model of SZ has shown that administration of an α5GABA-A modulating drug rescues the psychosis-like phenotype (hyperdopaminergia) (Gill, Lodge, Cook, Aras, & Grace, 2011). However, this rescue does not occur if the animals are previously administered the first-generation antipsychotic haloperidol (Gill, Cook, Poe, & Grace, 2014). A recent study in patients with first-episode psychosis found increased baseline GABA levels as measured by magnetic resonance spectroscopy (de la Fuente-Sandoval et al., 2017). After 4 weeks of treatment with the antipsychotic risperidone, these GABA levels normalized in the medial prefrontal cortex and decreased at a trend level in the dorsal caudate (de la Fuente-Sandoval et al., 2017). All in all these studies suggest that antipsychotic medication besides directly regulating the dopaminergic system may also be acting on the GABAergic system, but the underlying mechanisms remain unknown. The aim of our study was thus to investigate, for the first time, the effects of clinically-relevant dosages of haloperidol on α5GABA-A R and benzodiazepine-sensitive α1–3;5GABA-A R in healthy rats.MethodsA total of 36 male Sprague-Dawley rats were treated with vehicle, haloperidol 0.5 mg/kg/day or 2 mg/kg/day with an osmotic minipump for 28 days, representing clinically-relevant dosages of antipsychotic administration (Kapur, Vanderspek, Brownlee, & Nobrega, 2003). Quantitative autoradiography was conducted with [3H]Ro15-4513 and [3H]flumazenil, to assess the effects of haloperidol on α5GABA-A R and overall α1–3;5GABA-A R. Optical density measurements from cortical and subcortical regions were obtained from the autoradiographs using the MCID Software and converted into radioactivity values using a robust linear regression on GraphPad Prism. All data were analyzed using a mixed-effects model ANOVA on the same software and considered significant at p<0.05 with FDR correction for multiple comparisons.ResultsAdministration of chronic haloperidol showed a dose-specific increase in [3H]Ro15-4513 in the dorsal CA1 area of the hippocampus, showing an increase in binding in the 0.5 mg/kg/day vs. vehicle (p<0.01; q<0.01) and a decrease in the 2 mg/kg/day vs. the 0.5 group (p<0.05; q<0.01). In the nucleus accumbens, there was a significant reduction in [3H]Ro15-4513 binding in the higher-dose group compared to the 0.5 mg/kg/day group (p<0.001; q<0.001). In contrast, haloperidol exposure relayed a general increase in [3H]flumazenil binding across all the regions of interest explored (p<0.05).DiscussionThis is the first study to investigate, in healthy rats, the effects of clinically-relevant doses of haloperidol on GABA-A R binding in a receptor-subtype specific manner. Our results show that exposure to haloperidol causes changes in α5GABA-A R predominantly in the dorsal CA1 and the nucleus accumbens. An overall change in benzodiazepine-sensitive α1–3;5GABA-A R is also observed, irrespective of region. These results suggest that exposure to antipsychotic medication impacts the GABAergic system and should be considered when testing new pharmacological strategies in humans that have been exposed to antipsychotic medication.

Haloperidol affects coupling between QT and RR intervals in guinea pig isolated heart

Prolonged QT interval is an independent risk factor for development of ventricular arrhythmias. Haloperidol is one of the drugs inducing QT prolongation. Previous studies showed that haloperidol affects not only QT duration but also heart rate (RR interval). The present work focused on relationship between QT and RR and its changes under acute and chronic haloperidol administration. The study included 14 male guinea pigs divided into control and haloperidol-treated group. After 21-days administration of haloperidol or vehiculum, electrograms in isolated hearts were recorded. QT/RR and dQT/dRR coupling were calculated. Chronic haloperidol administration significantly decreases the coupling between QT and RR. Acute haloperidol exposure significantly decreases the dQT/dRR coupling in both treated and untreated guinea pig hearts. Flatter QT/RR relationship reveals a lack of QT adaptation to increased heart rate. It should be emphasized that in such situation ECG recording will not show significant QT prolongation evaluated according to clinical rules. However, if QT interval does not adapt to increased heart rate sufficiently, the risk of ventricular arrhythmias may be increased despite practically normal QT interval length. The results are supported by findings in biochemical analyses, which proved eligibility of the used model.

EVALUATION OF NEUROPHARMACOLOGICAL ACTIVITY OF MEDICINAL PLANT

Objective: The objective of the study is to evaluate the antiparkinsonian activity of hydroalcoholic extract of the seeds of Canavalia gladiata (HECG) in zebrafish and Swiss albino mice.Materials and Methods: Catalepsy was induced in zebrafish by exposing them to haloperidol solution. Treatment groups were exposed to bromocriptine and HECG, 30 min before haloperidol exposure at the dose of 2, 5, and 10 μg/mL. Latency to travel from one fixed point to another, time spent near the bottom of the tank, and complete cataleptic time were evaluated to assess behavioral changes. In mice, catalepsy was induced using haloperidol (1 mg/kg i.p.). Treatment groups received bromocriptine (2.5 mg/kg) and HECG at the dose of (100, 200, and 300 mg/kg) orally. Bar test for catalepsy, motor coordination test by rotarod, and locomotor activity by actophotometer were carried out to assess behavioral changes.Results: Bromocriptine and HECG-treated groups showed significant difference in behavioral parameters as compared to haloperidol control group in both the experimental models.Conclusion: Canavalia gladiata seeds exhibited significant antiparkinsonian activity in haloperidol mouse model and zebrafish. Zebrafish can be used with ease and effectiveness for initial screening of drugs before subjecting them to rodent testing.

Prenatal Exposure to Antipsychotics Disrupts the Plasticity of Dentate Neurons and Memory in Adult Male Mice.

BackgroundWith the growing use of second-generation antipsychotics for the treatment of a spectrum of psychiatric illnesses in pregnancy, concerns have been raised about the long-term impact of these medications on offspring neurodevelopment. However, preclinical and clinical evidence on the lasting effects of prenatal antipsychotic exposure is still sparse.MethodsRisperidone, a widely used second-generation antipsychotic, and haloperidol, a representative first-generation antipsychotic, were administered to pregnant C57BL/6N mice from embryonic day 6 to 16. Behavioral tests, immunohistochemical staining, Golgi-Cox technique, and western blot were used to determine the effects of prenatal antipsychotic exposure on the plasticity of the dentate gyrus and related behavior in adult male mice.ResultsBoth prenatal haloperidol- and risperidone-exposed mice showed recognition memory deficits but had no anxiety-related behavior. In addition, both prenatal haloperidol and risperidone exposure impaired the proliferation and maturation of adult-born dentate granule cells. We found that haloperidol exposure decreased dendritic length of dentate granule cells, while risperidone had no effect. However, both drugs inhibited dendrite branching in granule cells. Haloperidol exposure also significantly reduced total spine density in the middle dendritic segment of dentate gyrus. Prenatally risperidone-exposed mice only displayed a loss in thin and mushroom spines of infrapyramidal blade of dentate gyrus. Collectively, prenatal haloperidol exposure exerted more robust negative effects than risperidone.ConclusionThese data provide evidence for the long-term programming effects of early-life exposure to antipsychotics on hippocampal plasticity and behavior.

Antipsychotic-induced disorders: Reported cases and prospective study on muscle biomarkers after high exposure to haloperidol

Antipsychotic drugs are known to induce neuromuscular effects. In this study, we review 13 years (2002–2014) of antipsychotic intoxications reported by the anti-poisoning center of Algiers (APCA). The most recorded symptoms were neuromuscular/muscular disorders, of which haloperidol was the most inducer among all antipsychotics. A prospective study was conducted between December 2012 and January 2017 to evaluate muscle effects generated after intentional or accidental ingestion of haloperidol. Fifty-one patients admitted in different emergency departments in Algiers were included in this study. Urine and blood samples were collected from each patient for biological and toxicological monitoring and a group of healthy volunteers was assessed for comparison purpose. There was no significant difference in plasma lactate dehydrogenase (LDH) activity between healthy volunteers and exposed patients even when high levels of haloperidol were recorded. In contrast, selenium concentration and creatine kinase (CK) activity in plasma samples were significantly higher in patients exposed to high levels of haloperidol compared to healthy volunteers. Large percentage of patients exposed to high levels of haloperidol presented a significant elevated CK activity and high selenium concentration regarding the physiological thresholds. Additionally, CK activity and selenium concentration correlated positively with plasma content of haloperidol suggesting a dose-dependent relationship.In conclusion, some biomarkers (CK and selenium) may reflect muscle adverse effects of high haloperidol exposure that result possibly from muscle rigidity.

Influence of Gonadal Hormones on Motivation for a Sucrose Reward in Female Rats: Alterations following Exposure to Haloperidol and Apomorphine

IntroductionSex differences in dysfunction of motivational systems for natural rewards has been implicated in several disorders, including depression, obesity, and substance abuse (Pulcu &amp; Elliott, 2015; Volkow &amp; Wise, 2005). Sex differences are evident in these motivational disorders, and our lab has previously shown that female rats work harder for a natural sucrose reward compared to male rats. Interestingly, dopamine regulates motivated behaviors and may be important for understanding these sex differences in motivation. Previous research has found that haloperidol and apomorphine decrease responding for sucrose rewards, and gonadal hormones may influence sensitivity to these dopaminergic alterations. Although the role of gonadal hormones on motivation for drug rewards such as cocaine has been studied, little research has measured motivation for a natural sucrose reward following hormone manipulation. Further, it is not known if gonadal hormones alter sensitivity to haloperidol and apomorphine, as measured by responding for a sucrose reward. Therefore, the current study investigated the role estrogen and progesterone had on motivation for a sucrose reward and how these hormones alter sensitivity to dopaminergic manipulations (i.e. haloperidol and apomorphine injections).MethodsSeventy adult female rats were randomly assigned to one of five experimental groups: intact, ovariectomized (ovx) that received vehicle, ovx that received estradiol benzoate, ovx that received progesterone, or ovx that received both estradiol benzoate and progesterone. All rats were trained to lever press on an autoshaping schedule followed by an increasing fixed ratio schedule (FR1, FR3, FR5). Rats were then given three progressive ratio (PR) tests to assess motivation following gonadal hormone manipulation, a .032 mg/kg haloperidol injection, or a .032 mg/kg apomorphine injection. Throughout training and testing, hormones were administered every four to five days to mimic the endogenous estrous cycle. Estradiol benzoate was administered 48 hours and progesterone administered 4 hours prior to each PR test.ResultsNeither ovx nor hormone restoration altered the number of active lever presses, suggesting similar motivational responding across all groups. The dopamine antagonist haloperidol decreased active lever responding overall compared to PR responding without drug, but hormone condition did not influence this change. The dopamine agonist apomorphine differentially altered responding, depending on the hormone condition. Ovx females receiving estradiol with progesterone had significantly greater active lever responding compared to ovx females receiving vehicle following apomorphine. However, neither estradiol benzoate nor progesterone treated females differed from ovx with vehicle.DiscussionGonadal hormones do not seem to influence motivation for a sucrose reward in female rats or responding following haloperidol exposure. However, gonadal hormones alter behavioral sensitivity to apomorphine. These findings suggest gonadal hormones may contribute to altered sensitivity to dopaminergic manipulations, which has implications for disorders such as depression, obesity, and substance abuse.

Chronic exposure to haloperidol and olanzapine leads to common and divergent shape changes in the rat hippocampus in the absence of grey-matter volume loss.

One of the most consistently reported brain abnormalities in schizophrenia (SCZ) is decreased volume and shape deformation of the hippocampus. However, the potential contribution of chronic antipsychotic medication exposure to these phenomena remains unclear. We examined the effect of chronic exposure (8 weeks) to clinically relevant doses of either haloperidol (HAL) or olanzapine (OLZ) on adult rat hippocampal volume and shape using ex vivo structural MRI with the brain retained inside the cranium to prevent distortions due to dissection, followed by tensor-based morphometry (TBM) and elastic surface-based shape deformation analysis. The volume of the hippocampus was also measured post-mortem from brain tissue sections in each group. Chronic exposure to either HAL or OLZ had no effect on the volume of the hippocampus, even at exploratory thresholds, which was confirmed post-mortem. In contrast, shape deformation analysis revealed that chronic HAL and OLZ exposure lead to both common and divergent shape deformations (q = 0.05, FDR-corrected) in the rat hippocampus. In particular, in the dorsal hippocampus, HAL exposure led to inward shape deformation, whereas OLZ exposure led to outward shape deformation. Interestingly, outward shape deformations that were common to both drugs occurred in the ventral hippocampus. These effects remained significant after controlling for hippocampal volume suggesting true shape changes. Chronic exposure to either HAL or OLZ leads to both common and divergent effects on rat hippocampal shape in the absence of volume change. The implications of these findings for the clinic are discussed.

Investigation into effects of antipsychotics on ectonucleotidase and adenosine deaminase in zebrafish brain.

Antipsychotic agents are used for the treatment of psychotic symptoms in patients with several brain disorders, such as schizophrenia. Atypical and typical antipsychotics differ regarding their clinical and side-effects profile. Haloperidol is a representative typical antipsychotic drug and has potent dopamine receptor antagonistic functions; however, atypical antipsychotics have been developed and characterized an important advance in the treatment of schizophrenia and other psychotic disorders. Purine nucleotides and nucleosides, such as ATP and adenosine, constitute a ubiquitous class of extracellular signaling molecules crucial for normal functioning of the nervous system. Indirect findings suggest that changes in the purinergic system, more specifically in adenosinergic activity, could be involved in the pathophysiology of schizophrenia. We investigated the effects of typical and atypical antipsychotics on ectonucleotidase and adenosine deaminase (ADA) activities, followed by an analysis of gene expression patterns in zebrafish brain. Haloperidol treatment (9 µM) was able to decrease ATP hydrolysis (35%), whereas there were no changes in hydrolysis of ADP and AMP in brain membranes after antipsychotic exposure. Adenosine deamination in membrane fractions was inhibited (38%) after haloperidol treatment when compared to the control; however, no changes were observed in ADA soluble fractions after haloperidol exposure. Sulpiride (250 µM) and olanzapine (100 µM) did not alter ectonucleotidase and ADA activities. Haloperidol also led to a decrease in entpd2_mq, entpd3 and adal mRNA transcripts. These findings demonstrate that haloperidol is an inhibitor of NTPDase and ADA activities in zebrafish brain, suggesting that purinergic signaling may also be a target of pharmacological effects promoted by this drug.

Chronic haloperidol increases voltage-gated Na+ currents in mouse cortical neurons

Typical antipsychotics are characterized by extrapyramidal syndrome (EPS). Previous studies demonstrated that typical antipsychotics could inhibit neuronal voltage-gated sodium channel (VGSC). However, EPS typically emerge only upon prolonged exposure. As a result, we examined effects of haloperidol, a prototype typical antipsychotic, on neuronal VGSC upon incubation for varying duration. Briefly, VGSC currents were activated and recorded using a whole-cell patch-clamp technique in primary culture of mouse cortical neurons. VGSC activity was inhibited by acute haloperidol exposure (for minutes), but enhanced in a time- and concentration-dependent manner by chronic haloperidol exposure (for hours). The effects of chronic haloperidol were associated with increased expression of VGSC subunits as well as corresponding electrophysiological channel properties. In summary, we found enhanced VGSC currents upon chronic haloperidol exposure in cortical neurons in contrast to inhibition by acute haloperidol exposure. Such a results may contribute to EPS of typical antipsychotics.

Studies on sensitivity of zebrafish as a model organism for Parkinson's disease: Comparison with rat model.

Objective:To determine the utility of zebra fish as an animal model for Parkinson's disease (PD) in comparison with rat model.Materials and Methods:MTT assay was performed on rat and zebrafish brain synaptosomal fractions using rotenone as a neurotoxic agent. Quercetin and resveratrol were used as standards to compare anti-apoptotic activity in both organisms. Catalepsy was induced in zebrafish by exposing them to haloperidol (9 μM) solution. Drug-treated groups were exposed to bromocriptine and pramipexole, 30 min prior to haloperidol exposure at the dose of 2, 5, and 10 μg/mL. Swimming speed, time spent in the bottom of the tank, and complete cataleptic time were evaluated to assess behavioral changes. In rats, catalepsy was induced using haloperidol (1.25 mg/kg i.p.). Drug-treated groups received bromocriptine (2.5 mg/kg.) and pramipexole (1 mg/kg) orally. Bar test, block test, and locomotor activity were carried out to assess behavioral changes.Results:Resveratrol and quercetin showed comparable inhibition of apoptosis in rats and zebrafish. In anti-cataleptic study, bromocriptine and pramipexole-treated groups showed significant difference (P < 0.05) in behavioral parameters as compared to haloperidol control group in both the experimental organisms. Results obtained from fish model were in correlation with rat model.Conclusion:Findings of the present study revealed that zebrafish model is highly sensitive and can be used for basic screening of drugs against PD.

Population Pharmacokinetic-Pharmacodynamic Modeling of Haloperidol in Patients With Schizophrenia Using Positive and Negative Syndrome Rating Scale

The aim of this study was to develop a pharmacokinetic-pharmacodynamic (PKPD) model that quantifies the efficacy of haloperidol, accounting for the placebo effect, the variability in exposure-response, and the dropouts. Subsequently, the developed model was utilized to characterize an effective dosing strategy for using haloperidol as a comparator drug in future antipsychotic drug trials. The time course of plasma haloperidol concentrations from 122 subjects and the Positive and Negative Syndrome Scale (PANSS) scores from 473 subjects were used in this analysis. A nonlinear mixed-effects modeling approach was utilized to describe the time course of PK and PANSS scores. Bootstrapping and simulation-based methods were used for the model evaluation. A 2-compartment model adequately described the haloperidol PK profiles. The Weibull and Emax models were able to describe the time course of the placebo and the drug effects, respectively. An exponential model was used to account for dropouts. Joint modeling of the PKPD model with dropout model indicated that the probability of patients dropping out is associated with the observed high PANSS score. The model evaluation results confirmed that the precision and accuracy of parameter estimates are acceptable. Based on the PKPD analysis, the recommended oral dose of haloperidol to achieve a 30% reduction in PANSS score from baseline is 5.6 mg/d, and the corresponding steady-state effective plasma haloperidol exposure is 2.7 ng/mL. In conclusion, the developed model describes the time course of PANSS scores adequately, and a recommendation of haloperidol dose was derived for future antipsychotic drug trials.

Monitoring Haloperidol Exposure in Body Fluids and Hair of Children by Liquid Chromatography–High-Resolution Mass Spectrometry

Haloperidol, 4-[4-(4-chlorophenyl)-4-hydroxy-1-piperidinyl]-1-(4-fluorophenyl)-1-butanone (HP), one of the most widely used antipsychotics in the treatment of schizophrenia, mania, and other psychiatric disorders, is frequently encountered in cases of unintentional pediatric intoxication because the ingestion of a small amount can cause significant toxic effects in children. For monitoring HP in suspected ingestions, a liquid chromatography-high-resolution mass spectrometry method has been developed and validated in urine, blood, and hair samples. The analyte was extracted from 1 mL blood or urine by liquid/liquid extraction and from 5 mg of hair by micropulverized extraction; gradient elution on an Atlantis T3 column was realized using HP-d4 as an internal standard. Positive ion electrospray ionization and high-resolution mass spectrometry determination were performed in an Orbitrap mass spectrometer. The method exhibited a r > 0.999 in the studied ranges (0.1-50 ng/mL in urine and blood and 0.1-50 ng/mg in hair) and a limit of quantification of 0.1 ng/mL for urine and blood and 0.1 ng/mg for hair; intra-assay and interassay relative SDs were always more than 18%. The method was applied to determine haloperidol in 3 children who were admitted to emergency departments. HP concentrations ranged from 2 to 21 ng/mL in urine, from not detected to 4.9 ng/mL in blood, and from 0.37 to 0.73 ng/mg in hair samples. The utilization of high-resolution/high-accuracy mass spectrometry in full scan mode allowed the identification of HP metabolites in urine and blood, thus unequivocally documenting the exposure to the drug. HP metabolites were structurally characterized by high-resolution multiple mass spectrometry. For the first time, a HP metabolite was detected in hair.