Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0036341 (schizophrenia)
 60,220 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

HO-2 is a constitutive isoform of heme oxygenase (HO), a microsomal enzyme that catalyzes the cleavage of the heme ring to form ferrous iron, carbon monoxide, and biliverdin. In contrast to HO-1, which is inducible, HO-2 is not responsive to stimuli tested to date except for prolonged exposure to the adrenal glucocorticoids (GCs). Previous studies have shown that high GC concentrations or stress damage or kill hippocampal neurons. In the present study, it was found that chronic restraint stress decreased HO-2 protein levels in hippocampal neurons, as demonstrated by immunohistochemistry and Western blot analysis. Moreover, our results showed that the combination of 2.5mg/kg of venlafaxine and 5mg/kg of quetiapine effectively prevented the HO-2 protein decrease in hippocampal neurons of stressed rats, whereas either of the drugs alone did not show any effect. At higher dose levels, both quetiapine (10mg/kg) and venlafaxine (5mg/kg) produced significant effects comparable to that of their combination. Quetiapine is an atypical antipsychotic and venlafaxine an antidepressant. In previous studies, these two drugs have been shown to prevent or protect against the stress-induced decrease in hippocampal neurogenesis and BDNF expression. These data suggest that both quetiapine and venlafaxine share the hippocampus as their common target by enhancing hippocampal resilience, which may be impaired in patients with schizophrenia or depression.
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PMID:Quetiapine and venlafaxine synergically regulate heme oxygenase-2 protein expression in the hippocampus of stressed rats. 1611 34

Previous studies have demonstrated that adult rats with excitotoxic lesions of the hippocampus display deficits in memory-related behaviors similar to the memory deficits associated with schizophrenia. In this study, we assessed the sub-chronic effects of quetiapine, risperidone and haloperidol on performance deficits after intracerebroventricular administration of the excitotoxin, kainic acid, using paradigms for contextual and cued fear conditioning and spatial reversal learning in rats. The effects of three doses of quetiapine (5, 10 and 20 mg/kg) and single doses of risperidone (0.5 mg/kg) and haloperidol (0.15 mg/kg) were compared. Quetiapine administration at the lowest dose (5 mg/kg) reversed deficits in contextual and cued fear conditioning, but not deficits in spatial reversal learning, in kainic acid-treated animals. However, the two higher doses of quetiapine, and the single doses of risperidone and haloperidol, did not reverse any of the kainic acid-induced behavioral deficits. These results may be relevant to the effects of quetiapine and other antipsychotic drugs on memory deficits in patients with schizophrenia.
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PMID:Low dose quetiapine reverses deficits in contextual and cued fear conditioning in rats with excitotoxin-induced hippocampal neuropathy. 1618 7

To quickly reduce symptoms and to optimize long-term outcome, patients with an acute episode of schizophrenia or mania require prompt treatment intervention. The atypical antipsychotic quetiapine ('Seroquel') has been approved for the treatment of schizophrenia and manic episodes associated with bipolar disorder. For patients with acute symptoms such as aggression or agitation, higher doses of quetiapine than the recommended initiation schedule are often required. This report presents the tolerability findings from rapid initiation with high-dose quetiapine for eight patients who were consecutively admitted with acute symptoms of schizophrenia (n 5) or mania (n 3). The results from this case series show that quetiapine treatment could be safely titrated at a more rapid rate and to doses greater than that described in the current prescribing information. For most patients, rapid dose escalation was well tolerated; no serious side effects were observed and vital clinical parameters were unchanged; one patient experienced transient somnolence. In conclusion, these results suggest that rapid dose escalation of quetiapine could be a useful treatment approach for acutely ill patients with schizophrenia and bipolar mania in order to improve acute symptoms and support the need for randomized controlled trials. However, dose adjustments should be considered with respect to each patient's individual level of tolerability.
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PMID:Rapid dose titration of quetiapine for the treatment of acute schizophrenia and acute mania: a case series. 1620 26

Atypical antipsychotics are generally thought to be more effective than conventional agents in treating the negative symptoms of schizophrenia; however, there have been few direct comparisons among atypicals. We therefore investigated risperidone and quetiapine with respect to their efficacy against negative symptoms in a 12-week,double-blind, comparative pilot study involving 44 patients with schizophrenia with predominantly negative symptoms, as defined by Positive and Negative Syndrome Scale (PANSS) scores. Other efficacy measures included the Scale for the Assessment of Negative Symptoms (SANS) and the Clinical Global Impression (CGI) rating scale. Antipsychotic tolerability was assessed using the Simpson-Angus Scale (SAS) and various laboratory measures. Mean doses were 589.7 mg/ day quetiapine and 4.9 mg/day risperidone (observed cases). Both antipsychotics produced significant decreases in PANSS total, positive and negative scores, and SANS scores. Patients receiving risperidone were significantly more likely to experience extrapyramidal symptoms (EPS) [p <0.05], or to require anticholinergic medication (p <0.05), and had significantly higher prolactin levels (p <0.001) than quetiapine-treated patients. In conclusion, there is no significant difference in efficacy between quetiapine and risperidone in alleviating the negative symptoms of schizophrenia. Quetiapine is also well tolerated, with a lower incidence of EPS and prolactin increase than risperidone.
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PMID:Quetiapine has equivalent efficacy and superior tolerability to risperidone in the treatment of schizophrenia with predominantly negative symptoms. 1626 34

Quetiapine is an atypical antipsychotic effective in treating the positive, negative, and cognitive symptoms of patients with schizophrenia. Our previous study has shown that chronic administration of quetiapine attenuates the decrease in levels of brain-derived neurotrophic factor (BDNF) in the hippocampi of rats subjected to chronic-restraint stress. In the present study, we investigated the effects of quetiapine on hippocampal neurogenesis that had been compromised in stressed rats. Newborn cells in the hippocampus were labeled by bromodeoxyuridine (BrdU), and immature neurons were detected immunohistochemically using an antibody against phosphorylated cAMP response element-binding protein (pCREB). The restrained rats (4 h/day for 7 days) showed lower levels of hippocampal neurogenesis indicated by decreased numbers of BrdU-labeled and pCREB-positive cells. Post-stress administration of quetiapine (10 mg/kg) for 7 or 21 days reversed the stress-induced suppression of hippocampal neurogenesis, evidenced in the numbers of BrdU-labeled and pCREB-positive cells that are comparable to those in non-stressed rats but higher than those in the vehicle-treated rats. The results may help us understand the therapeutic effects of quetiapine on cognitive deficits in patients with schizophrenia and depression, in which the structure and functions of the hippocampus are implicated.
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PMID:Quetiapine reverses the suppression of hippocampal neurogenesis caused by repeated restraint stress. 1627 9

Quetiapine (Seroquel), an atypical antipsychotic with established efficacy in the treatment of schizophrenia, shows efficacy in the treatment of acute mania and depression associated with bipolar disorder.Quetiapine, either as monotherapy or in combination with lithium or divalproex sodium (valproate semisodium), is generally well tolerated and effective in reducing manic symptoms in adult and adolescent patients with acute bipolar mania, and is approved for use in adults for this indication. As monotherapy, the drug is also effective in reducing depressive symptoms in patients with bipolar depression. It is associated with a low incidence of extrapyramidal symptom (EPS)-related adverse events and low EPS ratings in bipolar disorder. Quetiapine thus shows potential in the treatment of bipolar depression, and represents a useful agent for the treatment of acute bipolar mania.
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PMID:Quetiapine: a review of its use in acute mania and depression associated with bipolar disorder. 1629 76

Quetiapine, a new atypical antipsychotic drug, effectively alleviates positive and negative symptoms, as well as cognitive impairment that may be caused by neurodegeneration, in schizophrenia patients. Earlier in vivo and in vitro studies have demonstrated that quetiapine may be a neuroprotectant. The present study was designed to examine the beneficial effects of quetiapine on the possible cognitive impairment and changes of brain apoptotic regulation proteins induced by phencyclidine (PCP) in rats. Rats were treated with quetiapine (10 mg/kg/day; intraperitoneal (i.p.)) or vehicle for 16 days. On day 14, 1 h after the administration of quetiapine, the rats were given PCP (50 mg/kg; subcutaneous (s.c.)) or vehicle. Then quetiapine was administrated for an additional 2 days. One day after the last quetiapine injection (3 days after the PCP injection), the rats were trained on a spatial memory task in a radial arm maze. After the behavioural test, the rats were decapitated for Western blot analysis. PCP induced reference memory impairment, and a decrease of the ratio of an anti-apoptotic Bcl-2 family member (Bcl-XL) to a pro-apoptotic analogue (Bax) in the posterior cingulate cortex. Chronic administration of quetiapine counteracted the PCP-induced reference memory impairment and decrease of Bcl-XL/Bax ratio in the posterior cingulate cortex. These results suggest that quetiapine may have ameliorating effects on the cognitive impairment and brain apoptotic processes induced by PCP.
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PMID:The effects of chronic administration of quetiapine on the phencyclidine-induced reference memory impairment and decrease of Bcl-XL/Bax ratio in the posterior cingulate cortex in rats. 1636 Aug 89

Development of new antipsychotics and their novel applications may be facilitated through the use of physiological markers in clinically normal individuals. Both genetic and neurochemical evidence suggests that reduced prepulse inhibition of startle (PPI) may be a physiological marker for individuals at-risk for schizophrenia, and the ability of antipsychotics to normalize PPI may reflect properties linked to their clinical efficacy. We assessed the effects of the atypical antipsychotic quetiapine (12.5 mg p.o.) on PPI in 20 normal men with a 'low PPI' trait, based on PPI levels in the lowest 25% of a normal PPI distribution. The effects of quetiapine (7.5 mg/kg s.c.) on PPI were then assessed in rats with phenotypes of high PPI (Sprague Dawley (SD)) and low PPI (Brown Norway (BN)); effects of clozapine (7.5 mg/kg i.p.) and haloperidol (0.1 mg/kg s.c.) on PPI were also tested in SD rats. At a time of maximal psychoactivity, quetiapine significantly enhanced PPI to short prepulse intervals (20-30 ms) in 'low gating' human subjects. Quetiapine increased PPI in low gating BN rats for prepulse intervals <120 ms; this effect of quetiapine was limited to 20 ms prepulse intervals in SD rats, who also exhibited this pattern in response to clozapine but not haloperidol. In both humans and rats, normal 'low gating' appears to be an atypical antipsychotic-sensitive phenotype. PPI at short intervals may be most sensitive to pro-gating effects of these drugs.
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PMID:Antipsychotic effects on prepulse inhibition in normal 'low gating' humans and rats. 1648 83

Quetiapine is an atypical antipsychotic that has shown efficacy in the treatment of positive and negative symptoms in schizophrenia without causing extrapyramidal symptoms (EPS). To date, there are two monotherapy and two combination therapy studies with a double blind, placebo-controlled design on the use of quetiapine in mania. Several open studies and case reports support the results of the controlled trials suggesting that quetiapine is effective in treating the broad spectrum of manic symptoms and is tolerated well.
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PMID:[Quetiapine in the treatment of acute mania]. 1651 28

Quetiapine (Seroquel), an atypical antipsychotic with established efficacy in the treatment of schizophrenia, shows efficacy in the treatment of acute mania and depression associated with bipolar disorder.Quetiapine, either as monotherapy or in combination with lithium or divalproex sodium (valproate semisodium), is generally well tolerated and effective in reducing manic symptoms in adult and adolescent patients with acute bipolar mania, and is approved for use in adults for this indication. As monotherapy, the drug is also effective in reducing depressive symptoms in patients with bipolar depression. It is associated with a low incidence of extrapyramidal symptom (EPS)-related adverse events and low EPS ratings in bipolar disorder. Quetiapine thus shows potential in the treatment of bipolar depression, and represents a useful agent for the treatment of acute bipolar mania.
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PMID:Spotlight on quetiapine in acute mania and depression associated with bipolar disorder. 1669 84


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