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Effect of oral administration of haloperidol on plasma thyrotropin concentrations in men.

To investigate the effects of neuroleptics on plasma thyrotropin (TSH) concentrations, haloperidol tablets were administered orally to 34 normal male volunteers. Seventeen of the subjects received 4 mg; the other 17 received 10 mg. Plasma samples were collected at baseline and 1, 3, 4, 6, 14, 24, 36, 48, 72 and 96 hr after drug administration. Plasma TSH was assayed by a double antibody radioimmunoassay procedure. A significant change in plasma TSH occurred for all subjects (p less than 0.001). By multivariate analysis of variance, the dose x time interaction was not significant. However, a significant dose x time interaction was detected in a univariate analysis. After haloperidol 10 mg a statistically significant rise in TSH occurred at 3-4 hr, which corresponded to the time of attainment of maximal plasma haloperidol concentrations. A significant but modest correlation between plasma haloperidol and TSH was present at 3 hr (0.373; p less than 0.05). TSH concentrations at 14 hr after the 10 mg dose were not significantly correlated with simultaneous or peak plasma haloperidol concentrations. Consequently, only the release of TSH occurring at 3-4 hr after the 10 mg dose was attributed to the drug's effects.

Adolescent↗

Effects of haloperidol on motor and cognitive functioning in aged mice.

The effects of haloperidol on motor and functioning and cognitive functioning were studied in young (3-5 months old) and aged (20-22 months old) male mice by examining haloperidol-induced catalepsy and haloperidol-induced decrements in performance on a radial arm maze. The aged mice were much more sensitive to these adverse effects of haloperidol than were the young mice. Studies of the distribution of radioactivity from [3H]haloperidol to the brain indicated that the differences in sensitivity to this drug were not due to pharmacokinetic differences. The results demonstrate that mice are suitable for studies of aging-induced changes in the behavioral effects of neuroleptic agents.

Aging↗

Estimation of haloperidol concentrations in rat striatum after chronic treatment.

3H-Spiroperidol association and dissociation rate constants were determined in rat striatal homogenates in the presence of known concentrations of unlabelled haloperidol. The rate of 3H-spiroperidol association was progressively decreased in the presence of increasing concentrations of haloperidol and no changes were seen in 3H-spiroperidol dissociation rate constants. Measuring changes in 3H-spiroperidol association rate constants permitted detection of 0.1 pmol/ml unlabelled haloperidol in assay homogenates. Then, male Sprague-Dawley rats received daily injections of haloperidol (1.5 mg/kg) for 1-21 days. Twenty-four hours after the last injection, 3H-spiroperidol kinetic rate constants and Kd values were measured and found to be unchanged in all treatment groups. These findings suggest that, under these conditions of drug withdrawal and tissue preparation, which are widely employed in studies of chronic neuroleptic administration, residual haloperidol does not interfere with the estimation of 3H-spiroperidol binding parameters.

Animals↗

Dehydration is the first step in the bioactivation of haloperidol to its pyridinium metabolite.

Haloperidol was found to have a similar metabolic pathway to that of the neurotoxin N-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) in mice microsomal preparations. The 1,2,3,6-tetrahydropyridine derivative of haloperidol was detected in NADPH-fortified metabolic incubation mixtures of haloperidol. Incubation of this dehydrated haloperidol produced the pyridinium metabolite. These metabolites were confirmed by comparison with synthesised compounds using HPLC and HPLC-MS. Dehydration of an alcohol to a double bond represents a novel metabolic pathway. This novel metabolic pathway indicates a MPTP-like mechanism for the Parkinsonism observed with haloperidol in clinical use.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗

The effect of haloperidol in cocaine and amphetamine intoxication.

The effectiveness of haloperidol pretreatment in preventing the toxic effects of high doses of amphetamine and cocaine was studied in rats. In this model, toxic effects were induced by intraperitoneal (i.p.) injection of amphetamine 75 mg/kg (100% death rate) or cocaine 70 mg/kg (82% death rate). Haloperidol failed to prevent amphetamine-induced seizures, but did lower the mortality rate at most doses tested. Haloperidol decreased the incidence of cocaine-induced seizures at the two highest doses, but the lowering of the mortality rate did not reach statistical significance at any dose. These data suggest a protective role for the central dopamine blocker haloperidol against death from high-dose amphetamine exposure without reducing the incidence of seizures. In contrast, haloperidol demonstrated an ability to reduce cocaine-induced seizures without significantly reducing mortality.

Amphetamines↗

Differential modulation of mouse brain biogenic amines by haloperidol and pimozide: implications in Tourette's syndrome.

1. A comparison between the effect of equal dose regimens of Tourette's medications on mouse motor activity and regional brain monoamines suggests differential responses which may underlie drug-induced side-effects. 2. Haloperidol was more potent than pimozide in altering striatal dopamine concentration which may account for the greater incidence of haloperidol-induced extrapyramidal disorders compared to pimozide. 3. Pimozide, but not the haloperidol treatment, altered brain serotonin concentrations to suggest a decrease in turnover rate which may underlie pimozide-caused sedation in Tourette's syndrome. 4. Pimozide was more potent than haloperidol in duration of behavioral depression which suggests differential dopamine receptor subtypes blockade. 5. Pimozide was more potent than haloperidol in altering 3 of the 6 brain regions content of norepinephrine-derived normetanephrine which may be responsible for the increase in blood pressure reported during pimozide treatment.

Animals↗

[Ferrocene, ruthenocene and rhodocene analogs in haloperidol synthesis and organ distribution after labeling with 103Ru and 103mRh].

Ferrocene-Haloperidol was synthesized by N-alkylation of 4-(4'-chlorophenyl)- 4-hydroxypiperidine with 1-ferrocenyl-4-chlor-butan-1-on. By heating the ferrocene-haloperidol with 103RuCl3 the 103Ru-labelled ruthenocene-haloperidol was obtained. This compound showed a high affinity for lung but not for brain in rats and mice. The decay of the 103Ru labelled compound results in the formation of the 103mRh labelled rhodocene-haloperidol, which is rapidly oxidized by air to the corresponding rhodocinium-haloperidol. This compound can be separated by extraction and TLC.

Animals↗

Inverse agonism at dopamine D2 receptors. Haloperidol-induced prolactin release from GH4C1 cells transfected with the human D2 receptor is antagonized by R(-)-n-propylnorapomorphine, raclopride, and phenoxybenzamine.

Our earlier observation that the antipsychotic drug haloperidol in the absence of dopamine increases cAMP formation and prolactin release in two prolactin-producing cell lines expressing rat dopamine D2 receptors (GH3, GH4ZR7), but not in similar cells devoid of D2 receptors (GH4C1), prompted us to suggest that haloperidol may act as an inverse (or negative) agonist, rather than as a neutral antagonist, at the D2 receptor (Nilsson and Eriksson 1993). In the present study it is shown that haloperidol elicits a dose-dependent increase in prolactin release also in prolactin-producing GH4C1 cells transfected with the human dopamine D2 receptor (short isoform) (GH4C1-hD2s); in addition, it is shown that another antipsychotic drug, flupenthixol, also causes prolactin release per se in this cell line. The effect of haloperidol on prolactin release in GH4C1-hD2s is calcium dependent and counteracted by pretreatment either with the D2 receptor agonist R(-)-n-propylnorapomorphine or with a D2 receptor antagonist that does not affect prolactin release per se (raclopride). In addition, pretreatment with the alkylating compound phenoxybenzamine at a concentration causing a marked reduction of D2 receptor density in GH4C1-hD2s cells significantly counteracted haloperidol-induced prolactin release.

Animals↗

Effects produced by acute and chronic treatment with granisetron alone or in combination with haloperidol on midbrain dopamine neurons.

In this study, we examined the effects of acute and chronic administration of the 5-HT3 receptor antagonist granisetron (0.1, 1.0 or 10 mg/kg i.p.) alone or in combination with haloperidol (0.5 mg/kg i.p.) on the number of spontaneously active dopamine neurons in the substantia nigra pars compacta (SNC or A9) and the ventral tegmental area (VTA or A10). This was accomplished using the technique of extracellular single unit recording. Acute granisetron at 0.1 mg/kg, but not at higher doses, selectively decreased the number of spontaneously active A10 DA cells. Chronic administration of 0.1 or 1 mg/kg granisetron selectively decreased the number of spontaneously active A10 dopamine cells compared to controls, mimicking the effect produced by chronic treatment with the atypical neuroleptic drug clozapine. However, unlike the effect produced by neuroleptics, this granisetron-induced effect was not reversed by the systemic administration of apomorphine (50 micrograms/kg). These results suggest that the chronic granisetron-induced reduction of the number of spontaneous active dopamine cells is not the result of depolarization inactivation. Chronic coadministration of granisetron with haloperidol negates the effects produced by either compound alone. Acute coadministration of granisetron with haloperidol also attenuated or abolished haloperidol's action, particularly that on the A9 dopamine cells. Overall, it appears that at 0.1 and 1.0 mg/kg, chronic granisetron may possess atypical neuroleptic drug potential. However, the combination of haloperidol and granisetron nullifies changes in midbrain dopamine neurons observed with either agent alone.

Animals↗

Long-term neurocognitive effects of olanzapine or low-dose haloperidol in first-episode psychosis.

BACKGROUND: Neurocognitive deficits are severe in first-episode psychosis. METHODS: Patients (N = 263) with first-episode psychosis (schizophrenia, schizoaffective, or schizophreniform disorders) were randomly assigned to double-blind treatment with olanzapine (mean 11.30 mg/day) or haloperidol (mean 4.87 mg/day) for 104 weeks. A neurocognitive battery was administered at baseline (n = 246) and 12 (n = 167), 24 (n = 126), 52 (n = 89), and 104 (n = 46) weeks during treatment. Weighted principal component and unweighted composite scores were derived from individual tests. RESULTS: Both treatment groups demonstrated significant improvement on both composite scores. On the basis of the weighted composite score, olanzapine had greater improvement than haloperidol only at 12 (p = .014) and 24 (p = .029) weeks. For the unweighted composite, olanzapine had significantly better improvement compared with haloperidol only at week 12 (p = .044). At week 12 only, olanzapine improved performance on the Digit Symbol and Continuous Performance Test significantly more than haloperidol. CONCLUSIONS: Both antipsychotic agents appeared to improve neurocognitive functioning among first-episode psychosis patients with schizophrenia. A significantly greater benefit in terms of neurocognitive improvement was found with olanzapine than with haloperidol at weeks 12 and 24.

Adult↗

Streptozotocin-induced diabetes differentially modifies haloperidol- and gamma-hydroxybutyric acid (GHB)-induced catalepsy.

To examine whether dopamine-mediated behavioral effects are altered in diabetes, this study compared the cataleptic effects of the dopamine receptor antagonist haloperidol (0.032-0.56 mg/kg) and gamma-hydroxybutyric acid (GHB; 56-1000 mg/kg) in control and streptozotocin (STZ)-treated rats. Haloperidol and GHB produced catalepsy in control and diabetic rats; haloperidol was less potent in diabetic rats (D(50)=0.44 mg/kg) than in controls (D(50)=0.19 mg/kg), while GHB was more potent in diabetic rats (D(50)=392 mg/kg) than in controls (D(50)=550 mg/kg). In diabetic rats, the non-competitive N-methyl-d-aspartate (NMDA) receptor antagonist dizocilpine (0.32 mg/kg) further attenuated haloperidol-induced catalepsy (D(50)=1.2 mg/kg) and further enhanced GHB-induced catalepsy (D(50)=248 mg/kg). That haloperidol is less potent to produce catalepsy in diabetic rats is consistent with reports of altered dopamine receptor binding in diabetes.

Animals↗

Quetiapine or haloperidol as monotherapy for bipolar mania--a 12-week, double-blind, randomised, parallel-group, placebo-controlled trial.

METHODS: Patients (n=302) with bipolar I disorder (manic episode) were randomised to 12 weeks' double-blind treatment with quetiapine (flexibly dosed up to 800 mg/day), placebo, or haloperidol (up to 8 mg/day). The primary efficacy outcome variable was change from baseline to Day 21 in Young Mania Rating Scale (YMRS) score. RESULTS: YMRS score improved with quetiapine at Day 21 (-12.29 versus -8.32 for placebo; P<0.01). The difference in favor of quetiapine increased by Day 84 (-17.52 versus -9.48; P<0.001). Haloperidol also showed an advantage over placebo at Days 21 and 84 (P<0.001). There was no significant difference in efficacy measures between quetiapine and haloperidol groups at any assessment except Day 21. The only common adverse event with quetiapine was somnolence (12.7%). Extrapyramidal symptoms (EPS), including akathisia, occurred at 59.6% with haloperidol, 12.7% with quetiapine, 15.8% with placebo. Most quetiapine responders (84%) received a dose of 400-800 mg/day. CONCLUSIONS: Quetiapine was effective and well tolerated. The efficacy and tolerability profile of haloperidol (including its propensity for EPS) supported study validity.

Adult↗

Effects of haloperidol and melatonin on the in situ activity of nigrostriatal tyrosine hydroxylase in male Syrian hamsters.

Haloperidol, an antipsychotic drug, was tested for its effects on the in situ activity of nigrostriatal and hypothalamic tyrosine hydroxylase, in control male Syrian hamsters and in those receiving a high daily dose of melatonin. After receiving daily ip injections (1.25 mg/kg ip) of haloperidol for 21 days, the animals were sacrificed and brain tissue collected for analysis of dopamine and metabolites by HPLC with electrochemical detection. In situ activity of tyrosine hydroyxlase (TH) activity was determined by measuring the accumulation of L-Dopa after administration of the L amino acid decarboxylase inhibitor, mhydroxybenzylhydrazine. Tissue content of dopamine and its metabolites, DOPAC and HVA, was depressed in striatum of animals receiving haloperidol, and tyrosine hydroxylase (TH) activity was significantly decreased 20-24 h after the last injection (from 1823 +/- 63 to 1139 +/- 85 pg l-dopa/mg tissue). The decrease in TH activity in striatum was significantly inhibited by daily injections of a high dose of melatonin (2.5 mg/kg ip) (from 1139 +/- 85 to 1560 +/- 116 pg L-dopa/mg tissue). In the substantia nigra and in the hypothalamus, on the other hand, haloperidol significantly increased the activity of tyrosine hydroxylase. Melatonin administration did not significantly influence TH activity in the substantia nigra, but inhibited TH activity in the hypothalamus and in the pontine brainstem. One explanation for these data is that chronic haloperidol administration in Syrian hamsters increases TH activity in hypothalamus and substantia nigra, but decreases TH activity in striatum by a mechanism involving D2 presynaptic receptors and a melatonin sensitive kinase which regulates TH phosphorylation.

Animals↗

Impact of haloperidol and risperidone on gene expression profile in the rat cortex.

Despite the clinical efficacy of the most thoroughly studied conventional neuroleptic agent haloperidol, and the atypical antipsychotic risperidone is well established, little information is available on their molecular effects. Recent advances in high-density DNA microarray techniques allow the possibility to analyze thousands of genes simultaneously for their differential gene expression patterns in various biological processes, and to determine mechanisms of drug action. The aim of this series of experiments was to gain experience in antipsychotic gene-expression profiling and characterize (in the parlance of genomics) the "antipsychotic transcriptome." In this prospective animal study, broad-scale gene expression profiles were characterized for brains of rats treated with antipsychotics and compared with those of sham controls. We used DNA microarrays containing 8000 sequences to measure the expression patterns of multiple genes in rat fronto-temporo-parietal cortex after intraperitoneal treatment with haloperidol or risperidone. A number of transcripts were differentially expressed between control and treated samples, of which only 36 and 89 were found to significantly differ in expression as a result of exposure to haloperidol or risperidone, respectively (P<0.05). Acutely, 13 genes were more highly expressed and 15 transcripts were found to be significantly less abundant, whereas chronically nine genes were up-regulated and none of them was repressed in haloperidol-treated cortices. Risperidone acutely induced 43 and repressed 46 genes, and chronically over-expressed 6 and down-regulated 11 transcripts. Selected genes were assayed by real-time PCR, then normalized to beta-actin. These assays confirmed the significance of the array results for all transcripts tested. Despite their differing receptor affinity and selectivity, our findings indicate that haloperidol and risperidone interfere with cell survival, neural plasticity, signal transduction, ionic homeostasis and metabolism in a similar manner.

Animals↗

Haloperidol induces neurotoxicity by the NMDA receptor downstream signaling pathway, alternative from glutamate excitotoxicity.

The NMDA receptor is believed to be important in a wide range of nervous system functions including neuronal migration, synapse formation, learning and memory. In addition, it is involved in excitotoxic neuronal cell death that occurs in a variety of acute and chronic neurological disorders. Besides of agonist/coagonist sites, other modulator sites, including butyrophenone site may regulate the N-methyl-D-aspartate receptor. It has been shown that haloperidol, an antipsychotic neuroleptic drug, interacts with the NR2B subunit of NMDA receptor and inhibits NMDA response in neuronal cells. We found that NMDA receptor was co-immunoprecipitated by anti-Ras antibody and this complex, beside NR2 subunit of NMDA receptor contained haloperidol-binding proteins, nNOS and Ras-GRF. Furthermore, we have shown that haloperidol induces neurotoxicity of neuronal cells via NMDA receptor complex, accompanied by dissociation of Ras-GRF from membranes and activation of c-Jun-kinase. Inclusion of insulin prevented relocalization of Ras-GRF and subsequent neuronal death. Haloperidol-induced dissociation of Ras-GRF leads to inhibition of membrane-bound form of Ras protein and changes downstream regulators activity that results in the initiation of the apoptotic processes via the mitochondrial way. Our results suggest that haloperidol induces neuronal cell death by the interaction with NMDA receptor, but through the alternative from glutamate excitotoxicity signaling pathway.

Animals↗

The effects of haloperidol treatment on the distribution of NK1 receptor immunoreactive neurons in guinea-pig brain.

Previous studies have observed increased tachykinin NK(1) receptor immunoreactivity (NK(1)-IR) in the prefrontal cortex in subjects with schizophrenia. Since the subjects were medicated the possibility of a treatment effect could not be excluded. Thus, the present study was undertaken to determine the effect of chronic treatment with the antipsychotic drug, haloperidol, on the distribution of NK(1)-IR neurons in the guinea-pig brain. Guinea pigs were treated each day for 21 days with either haloperidol (1mg/kg) or vehicle and the brains were then processed for immunohistochemistry using an NK(1) receptor-specific polyclonal antibody. NK(1)-IR neurons and fibres were abundant in the forebrain cortex and caudate putamen and more sparsely distributed in a number of other brain regions. The relative density of NK(1)-IR neurons was significantly increased in the forebrain cortex, but not in the caudate putamen in guinea pigs treated with haloperidol. This study has shown that haloperidol causes region-specific changes to the density of NK(1)-IR neurons. Whether these changes are related to the therapeutic effects or to the side effects of haloperidol in individuals with schizophrenia, remains to be determined.

Animals↗

Somatodendritic and postsynaptic serotonin-1A receptors in the attenuation of haloperidol-induced catalepsy.

The mechanism by which stimulation of somatodendritic and/or postsynaptic 5-hydroxytryptamine (5-HT, serotonin)-1A receptor could attenuate acute Parkinsonian-like effects of typical antipsychotics is investigated by comparing the anticataleptic and neurochemical effects of 8-hydroxy-2-di-n-propylaminotetralin (8-OH-DPAT) and buspirone in rats injected with haloperidol. Cataleptic effects of a submaximal dose (1 mg/kg) of haloperidol were attenuated more by prior administration of 8-OH-DPAT (0.25 mg/kg) than buspirone (1 mg/kg). Striatal 5-HT metabolism decreased more in buspirone- than 8-OH-DPAT-injected animals. Administration of haloperidol did not alter 5-HT metabolism in saline-, 8-OH-DPAT- or buspirone-injected animals. Dopamine decreased and its metabolite homovanillic acid (HVA) increased in the striatum of rats injected with buspirone. Effects of 8-OH-DPAT on dopamine metabolism were not significant. Haloperidol-induced increases of dopamine metabolites were attenuated by prior administration of 8-OH-DPAT, but not buspirone. The mechanism by which stimulation of somatodendritic as well as postsynaptic 5-HT-1A receptors could attenuate haloperidol-induced catalepsy is discussed. The findings have potential implications in the treatment of schizophrenia and motor behavior.

8-Hydroxy-2-(di-n-propylamino)tetralin↗

Efficacy of olanzapine and haloperidol in an animal model of mania.

PURPOSE: Intracerebroventricular (ICV) administration of ouabain, a potent sodium pump inhibitor, has been used to model mania. Antipsychotic agents have demonstrated efficacy in the management of acute mania. This study was undertaken to determine the prophylactic efficacy of olanzapine and haloperidol in the ouabain mania model. METHODS: Male Sprague-Dawley rats (4-8/group) were treated with two haloperidol decanoate intramuscular shots one week apart (21 mg/kg) or twice daily olanzapine intraperitoneal injections at low dose (1 mg/kg/day) or high dose (6 mg/kg/day) for 7 days prior to ICV administration of ouabain. Open field locomotion was quantified at baseline and after ouabain administration. RESULTS: Ouabain caused a significant increase in open field locomotion (253.7+/-SEM 55.12 vs control 53.1+/-12.13 squares traversed in 30 min in the olanzapine experiments, P<0.05; and 236.5+/-41.42 vs 129.3+/-38.23, P<0.05 in the haloperidol experiments). Olanzapine alone at low dose (102.2+/-37.7) or high dose (151.2+/-49.2) did not alter open field activity. Low dose olanzapine (176.6+/-73.27) but not high dose (307.5+/-167.32) caused a modest reduction of the ouabain effect. Haloperidol alone significantly reduced motoric activity compared to control (55.6+/-18.0, P<0.05), and prevented ouabain-induced hyperactivity (60.3+/-33.1, P<0.05). CONCLUSION: Haloperidol, but not olanzapine, demonstrated efficacy in this mania model, but methodological details may have reduced the effect of olanzapine.

Analysis of Variance↗