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Query: UMLS:C0011570 (depression)
 172,036 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Clozapine, a powerful neuroleptic with unique clinical efficacy (and without parkinsonic side effects), has been shown to have an unusual EEG profile. The EEG changes after clozapine, especially when instrumentally quantified, demonstrated the predictive value of EEG. The similarities of the EEG profile of clozapine with the profile of thymoleptic compounds indicated its possible thymoleptic effect. This later proved to be the case with therapeutic studies in depression. The EEG profile of clozapine in volunteers is similar to the EEG profile in schizophrenics (with appropriately higher doses). Instrumental quantification was performed with spectral and iterative interval analysis to show the advantages of each method and also the complementary value of both of them.
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PMID:EEG profile and behavioral changes after a single dose of clozapine in normals and schizophrenics. 33 39

In unrestrained cats clozapine in increasing doses (1--5 mg/kg) caused a behavioural depression and suppression of amphetamine-induced stereotypy of behaviour against the background of marked vegetative shifts. Similarly to chlorpromazine clozapine intensified the behavioural arrest reaction) and electrographic (neocortical caudate spindle) indices of the arrest function of the caudate nucleus. Arrest reaction changed more distinctly in stimulation of the ventral parts of the head of the nucleus. Clozapine also eliminated the weakening of the caudate responses caused by the stereotypical doses of amphetamine.
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PMID:[Effect of clozapine on the behavioral and electrographic indices of the arrest function of the caudate nucleus in cats]. 56 38

Parkinson's disease (PD) is frequently associated with psychiatric problems. Depression generally responds to antidepressant medications or to electroconvulsive therapy (ECT). The nondepressive psychoses generally require a reduction in parkinsonian medications, or possibly a "drug holiday." In patients whose psychosis fails to respond to a reduction in medication or who cannot tolerate the worsening parkinsonism, an antipsychotic drug should be added. Clozapine is probably the drug of choice, with low potency neuroleptics being second-line options.
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PMID:The management of the levodopa psychoses. 168 May 56

Clozapine is the first truly new antipsychotic drug introduced in the last 40 years. Compared to traditional neuroleptic agents, clozapine appears to have a stronger effect on most schizophrenic symptoms. Thus, it seems to be more effective than other agents in severely ill, treatment-resistant patients. Clozapine rarely causes extrapyramidal symptoms such as pseudoparkinsonism or akathisia. To date, no confirmed cases of tardive dyskinesia have been attributed to the drug. Despite these advantages, the usefulness of clozapine is limited by its potentially life-threatening side effects, which include agranulocytosis and respiratory depression.
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PMID:Clozapine: a novel antipsychotic. 173 62

The pharmacology, pharmacokinetics, clinical efficacy, adverse effects, dosage, and cost of the atypical antipsychotic drug clozapine are reviewed. Clozapine is a dibenzazepine compound chemically similar to loxapine but with a distinct pharmacologic profile. Unlike currently available medications, clozapine has a low potential for causing extrapyramidal symptoms and does not induce dopamine type 2 receptor hypersensitivity. It shows affinity in vitro not only for dopamine type 1 and 2 receptors but also for histamine type 1, alpha-adrenergic type 1 and 2, serotonin type 2, and muscarinic receptors. Clozapine given orally is nearly completely absorbed and readily metabolized. Urinary excretion is the major route of metabolite elimination. Clozapine has been used to treat schizophrenia, nonschizophrenic psychotic states, depression, neuroses, and behavioral disorders. Double-blind comparative studies have shown clozapine to be superior to haloperidol, chlorpromazine, and placebo in treating the symptoms of schizophrenia, as measured with validated psychiatric rating scales. Adverse effects include orthostatic hypotension, tachycardia, benign hyperthermia, hypertension, seizures, and sedation. Many of these effects are transient. Because of the risk of agranulocytosis, a comprehensive case-management system has been developed. In treating acute psychosis, the optimum dosage of clozapine is 300-450 mg/day given orally in divided doses. The high cost of clozapine may be offset by improved patient response and reduced hospital costs. Clozapine may be superior to other agents in the treatment of refractory schizophrenia and is associated with a negligible incidence of extrapyramidal symptoms.
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PMID:Clozapine: an atypical antipsychotic agent. 257 73

Tolerability of long term clozapine treatment (7-8 years) was investigated in 27 female patients (age 34-77 years). Diagnosis according to ICD 9 was schizophrenia in 21 patients, severe psychomotor agitation with mental deficiency in 4 patients and an "endogenous" depression in 2 patients. All patients had previously been treated with different neuroleptics but with inadequate response or distressing side effects. The duration of the disorder was 10-36 years, duration of hospitalisation 10-36 years. At the day of investigation the total dose of clozapine ranged from 52-826 g, the average total dose being 385 g. The daily dose of clozapine ranged from 75 to 600 mg, the average daily dose being 225 mg. Only 2 patients were treated exclusively with clozapine, the other 25 patients were also receiving other neuroleptics. Seventy eight per cent of the investigated patients complained about hypersalivation and 63% showed overweight. In 37% of the patients the EEG demonstrated abnormalities. Mild parkinsonism was reported in 15% and akathisia in 11% of the patients, all these patients being on combined treatment. Clozapine did not induce tardive dysakinesia (TD) in any of the patients within a treatment period of 7-8 years. It is concluded that a potential benefit of clozapine includes a low incidence of neurological side effects even after long term administration.
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PMID:Tolerability of long term clozapine treatment. 281 63

The activity of neurones in the substantial nigra and ventral tegmentum was recorded extracellularly in vitro. Dopamine produced depression of spontaneous firing in a dose-dependent manner. Antagonism of these neuronal responses to dopamine by metoclopramide, SCH 23390 and clozapine was examined. Metoclopramide antagonised the responses to dopamine in the manner expected; SCH 23390 had little effect on the response to dopamine as would be predicted for a selective dopamine "D1" antagonist. Clozapine did not produce the expected antagonism of the response to dopamine. The results at the single neurone level are compared with behavioural and biochemical data.
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PMID:Sensitivity of neuronal dopamine response in the substantia nigra and ventral tegmentum to clozapine, metoclopramide and SCH 23390. 329 79

Different types of neuroleptics were studied for pre- and postsynaptic alpha-adrenoceptor antagonism in pithed rats using the blood pressure effect of clonidine as a measure of postsynaptic alpha-adrenoceptor activation and the depression of the heart rate response to electrical stimulation as a measure of presynaptic alpha-adrenoceptor activation. Yohimbine (0.1 mg/kg) was more active at pre- than postsynaptic alpha-adrenoceptors while the reverse was found with prazosin (0.02-5 mg/kg). Phentolamine (1-5 mg/kg) on the other hand was very active at both receptors. Cocaine 1-5 mg/kg had no effect on these responses indicating that noradrenaline uptake inhibition presumably does not interfere with the revaluation of the alpha-adrenoceptor antagonistic effect of the neuroleptics. Melperone, haloperidol, thioridazine and flupenthixol (0.15 mg/kg) were more selective antagonists at postsynaptic alpha-adrenoceptors than prazosin. Clozapine, chlorprothixene showed preferential presynaptic (0.15 mg/kg) were antagonists at both types of receptors. Chlorprothixene showed preferential presynaptic alpha-antagonism of high potency. Chlorprothixene was the only neuroleptic drug which like phentolamine (1-5 mg/kg) gave complete presynaptic alpha-antagonism. These results indicate widely different selectivity of neuroleptics for pre- and postsynaptic alpha-adrenoceptors on peripheral sympathetic nerves. It is suggested that neuroleptics with presynaptic alpha-adrenoceptor antagonism may enhance the activity of Beta-adrenergic systems indirectly both in peripheral organs like the heart, and within the central nervous system.
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PMID:Pre- and postsynaptic alpha-adrenoceptor antagonism by neuroleptics in vivo. 611 64

This study deals with the characterization of 5-hydroxytryptamine (5-HT, serotonin) receptors positively linked to adenylyl cyclase in membranes from pig brain caudate. 5-HT and related agonists induced a concentration-dependent stimulation of adenylyl cyclase activity in pig caudate membranes, with the following rank order of potency (mean pEC50 values): 5-HT (7.1) > or = 5-methoxytryptamine (6.9) > 5-carboxamidotryptamine (5.6) > sumatriptan (< 5). Maximal stimulation by 5-HT averaged 35 pmol cyclic AMP/min/mg protein over a basal activity of 159 pmol cyclic AMP/min/mg protein. 5-Methoxytryptamine and 5-carboxamidotryptamine had similar efficacies to that of 5-HT, whereas sumatriptan was about half efficacious. Other compounds known as agonists at some 5-HT receptors were weakly potent (mean pEC50 values < 5). They include the 5-HT1A receptor agonist, 8-hydroxy-2-(di-n-propylamino)tetralin hydrobromide (8-OH-DPAT), the 5-HT4 receptor agonist, renzapride and the 5-HT2 receptor agonist, (1-(2,5-dimethoxy-4-iodophenyl)-2 aminopropane) (DOI). In antagonist studies, methiothepin (0.1 and 1 mumol/l) shifted the 5-HT curve to the right with no depression of the Emax, yielding pKB values of 7.4-8.0. Clozapine (1 mumol/l) also produced surmountable antagonism of 5-HT-induced effects (pKB 6.9). Ketanserin (10 mumol/l) weakly antagonized 5-HT (pKB 5.0). The 5-HT4 receptor antagonists, tropisetron (ICS 205-930) and SDZ 205-557 (2-methoxy-4-amino-5-chloro-benzoic acid 2-(diethylamino) ethyl ester), each at 1 mumol/l, did not significantly alter the concentration-response curve of 5-HT.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:5-Hydroxytryptamine receptors with a 5-HT6 receptor-like profile stimulating adenylyl cyclase activity in pig caudate membranes. 784 73

Neuroleptic medications are prescribed to millions of patients, but their use is limited by potentially irreversible extrapyramidal side effects. Haloperidol shows striking structural similarities to the neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine, which produces parkinsonism apparently through inhibition of NADH:ubiquinone oxidoreductase (complex I) of the mitochondrial electron transport chain. We now report that haloperidol, chlorpromazine, and thiothixene inhibit complex I in vitro in rat brain mitochondria. Clozapine, an atypical antipsychotic reported to have little or no extrapyramidal toxicity, also inhibits complex I, but at a significantly higher concentration. Neuroleptic treated patients have significant depression of platelet complex I activity similar to that seen in idiopathic Parkinson's disease. Complex I inhibition may be associated with the extrapyramidal side effects of these drugs.
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PMID:Neuroleptic medications inhibit complex I of the electron transport chain. 790 2


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