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)

N-methyl-D-aspartate (NMDA) glutamate receptor antagonists are used in clinical anesthesia and are being developed as therapeutic agents for preventing neurodegeneration in stroke, epilepsy, and brain trauma. However, the ability of these agents to produce neurotoxicity in adult rats and psychosis in adult humans compromises their clinical usefulness. In addition, an NMDA receptor hypofunction (NRHypo) state might play a role in neurodegenerative and psychotic disorders, like Alzheimer's disease, bipolar disorder and schizophrenia. Thus, developing pharmacological means of preventing these NRHypo-induced effects could have significant clinically relevant benefits. NRHypo neurotoxicity appears to be mediated by a complex disinhibition mechanism that results in the excessive stimulation of certain vulnerable neurons. Here we report our findings that five agents (phenytoin, carbamazepine, valproic acid, lamotrigine, and riluzole), thought to possess anticonvulsant activity because they inhibit voltage-gated sodium channels, prevent NRHypo neurotoxicity. The ability of tetrodotoxin, a highly selective inhibitor of voltage-gated sodium channels, to prevent the same neurotoxicity suggests that inhibition of this ion channel is the likely mechanism of action of these five agents. We also found that three other anticonvulsants (felbamate, gabapentin and ethosuximide), whose mechanism is less clear, also prevent NRHypo neurotoxicity, suggesting that inhibition of voltage-gated sodium channels is not the only mechanism via which anticonvulsants can act to prevent NRHypo neurotoxicity. Several of these agents have been found to be of clinical use in bipolar disorder. It would be of interest to determine whether these agents might have therapeutic benefits for conditions in which a NRHypo state may exist.
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PMID:Antiepileptic drugs and agents that inhibit voltage-gated sodium channels prevent NMDA antagonist neurotoxicity. 1219 17

Omega-3 (omega-3) is an essential fatty acid (EFA) found in large amounts in fish oil. It contains eicosapentaenoic acid and docosahexaenoic acid (DHA). DHA is one of the building structures of membrane phospholipids of brain and necessary for continuity of neuronal functions. Evidences support the hypothesis that schizophrenia may be the result of increased reactive oxygen species mediated neuronal injury. Recent reports also suggest the protective effect of omega-3 EFA against neuropsychiatric disorders including schizophrenia. This study proposed to assess the changes in antioxidant enzyme and oxidant parameters in the corpus striatum (CS) of rats fed with omega-3 EFA diet (0.4g/kg/day) for 30 days. Eight control rats and nine rats fed with omega-3 were decapitated under ether anesthesia, and CS was removed immediately. Thiobarbituric acid-reactive substances (TBARS) and nitric oxide (NO) levels as well as total superoxide dismutase (t-SOD) and xanthine oxidase (XO) enzyme activities in the CS were measured. Rats treated with omega-3 EFA had significantly lower values of TBARS (P<0.001), NO (P<0.002) and XO (P<0.005) whereas higher values of t-SOD enzyme activity (P<0.002) than the control rats. These results indicate that omega-3 EFA rich fish oil diet reduces some oxidant parameters in CS. This may be revealed by means of reduced CS TBARS levels as an end product of lipid peroxidation of membranes in treated rats. Additionally, reduced XO activity and NO levels may support this notion. On the other hand, although the mechanism is not clear, omega-3 EFA may indirectly enhance the activity of antioxidant enzyme t-SOD. Taken together, this preliminary animal study provides strong support for a therapeutic effect of omega-3 EFA supplemented to classical neuroleptic regimen in the treatment of schizophrenic symptoms and tardive dyskinesia.
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PMID:Potential role of dietary omega-3 essential fatty acids on some oxidant/antioxidant parameters in rats' corpus striatum. 1290 35

The three events, viz. schizophrenia, dissociative anaesthesia and Near-Death Experience, despite their seemingly unrelated manifestation to each other, have nevertheless similar functional basis. All three events are linked to the glutamate sensitive N-methyl-D-aspartate (NMDA) receptor complex, which serves as their common functional denominator. Arguments and speculations are presented in favor of the view that, the three events might be considered as functional models of each other. Antagonism to the recognition NMDA-site of the receptor induces dissociative anaesthesia and precipitates Near-Death Experience. Agonist reinforcement at the modulatory glycine-site of the receptor counteracts negative symptoms of schizophrenia. Both types of challenges towards the receptor are compatible with a glutamate deficiency concept which underlies the meeting of the three events at the NMDA receptor.
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PMID:Schizophrenia, dissociative anaesthesia and near-death experience; three events meeting at the NMDA receptor. 1472

Although electroconvulsive therapy (ECT) was first introduced to treat schizophrenia in 1938, it is widely used for the treatment of various major psychiatric disorders, including depression. In western countries, its safety has been improved with the introduction of techniques such as succinylcholine muscle relaxation, barbiturate anesthesia, oxygenation and brief-pulse stimulation. Although the first use of ECT in Japan was reported in 1939, few modifications of the ECT technique have been made since then. From the 1980s, in collaboration with anesthesiologists, ECT with anesthesia and muscle relaxation (modified ECT) has been administered in numerous general hospitals. Moreover, brief-pulse ECT devices were approved in 2002. Rapid progress in ECT practices is expected in Japan. Before administering ECT, informed consent should be obtained from the patient, except when the patient lacks capacity to consent. The major problems in ECT are cognitive side effects and high relapse rates. Furthermore, its mechanisms of action are still unknown. These problems must be solved in the near future.
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PMID:[Electroconvulsive therapy: past, present, and future]. 1523 Mar 52

Phospholipids located in the cellular membrane play a critical role in the fluid-mosaic model of membrane structure and membrane function. Evidence is mounting for the role of abnormal phospholipid metabolism in some neuropsychiatric disorders including schizophrenia. As an important essential fatty acid (EFA), omega-3 (omega-3) fatty acid series are found in large amounts in fish oil. The aim of this experimental study was to assess the changes of some of the oxidant and antioxidant parameters in the hypothalamus of rats fed with omega-3 EFA diet (0.4 g/kg/day) for 30 days. Eight control rats and nine rats fed with omega-3 were decapitated under ether anesthesia, and hypothalamus was removed immediately. Malondialdehyde (MDA) and nitric oxide (NO) levels as well as superoxide dismutase (SOD) and xanthine oxidase (XO) enzyme activities in the hypothalamus were measured. SOD activity was significantly decreased in omega-3 EFA treated group compared to control group (p < 0.014). Tissue MDA and NO levels were also decreased in omega-3 EFA treated group compared to control rats (p < 0.0001). Xanthine oxidase activity was found to be increased in omega-3 EFA treated rats when compared to the control group (p < 0.0001). Taken together, this preliminary animal study provides strong support for a therapeutic effect of omega-3 EFA in some neuropsychiatric disorders in which reactive oxygen species (ROS) are recently accused to be an important physiopathogenetic factor.
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PMID:Hypothalamic superoxide dismutase, xanthine oxidase, nitric oxide, and malondialdehyde in rats fed with fish omega-3 fatty acids. 1527 95

Phencyclidine (PCP) is a psychotomimetic drug that elicits schizophrenia-like symptoms in healthy persons, and administration of PCP to animals is used as a pharmacological model of schizophrenia. We recently demonstrated that systemic administration of PCP to rats produces long-lasting activation of medial prefrontal cortex (mPFC) neurons with augmentation of locomotor activity, whereas direct application of PCP to mPFC neurons has little effect on their firing activity. These findings suggest that PCP-induced activation of mPFC neurons is elicited mainly via excitatory inputs from regions outside the mPFC. In the present study, we examined effects of local application of PCP to the ventral hippocampus (vHIP) on firing activity of PFC neurons in freely moving rats. PCP locally perfused into the vHIP increased spontaneous discharges of PFC neurons during perfusion with augmentation of locomotor activity. Local application of a more selective NMDA receptor antagonist, MK801, to vHIP neurons under anesthesia increased the spontaneous firing rates of most neurons directly projecting to the mPFC, whereas local application of MK801 to mPFC neurons did not induce excitatory responses in any of those neurons. The present results indicate that tonic excitatory inputs from the vHIP to the PFC may trigger development of behavioral abnormalities.
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PMID:Activation of medial prefrontal cortex by phencyclidine is mediated via a hippocampo-prefrontal pathway. 1534 31

Among drugs used for the anesthesia of electroconvulsive therapy (ECT), propofol reduces seizure duration to a greater degree than etomidate. The perceived difference between the 2 anesthetics is smaller in patients with schizophrenia than in patients who suffer depression. In this study, propofol and etomidate were compared during the ECT of patients with schizophrenia, on the basis of their impact on seizure activity and on seizure-induced hemodynamic reactions. Schizophrenics (n = 34) who were treated with ECT participated in this randomized crossover study. Propofol (1 mg/kg) and etomidate (0.2 mg/kg) were used alternately. The 2 drugs were compared on the basis of EEG- and EMG-registered seizure duration, mean arterial pressure (MAP), pulse frequency, energy index, and postictal suppression. We also analyzed the number of necessary restimulations. In case of anesthesia with etomidate, both EEG- (61.29 +/- 22.4 s, 47.9 +/- 21.3 s P = 0.014) and EMG- (46.3 +/- 23.8 s, 33.6 +/- 15.9 s P = 0.006) registered seizure durations were significantly longer than in case of propofol. When using propofol, the increase in MAP was significantly lower than when etomidate was used (8.1 +/- 10.2 mm Hg, 18.3 +/- 11.2 mm Hg, P = 0.001). There were no significant differences found in the postseizure increase in pulse frequency, in postictal suppression, or in the energy index, nor did the numbers of necessary restimulations differ significantly. Propofol was found to reduce seizure duration to a significantly greater extent than etomidate. At the same time, in electrophysiological parameters that show a correlation with clinical efficacy, there was no significant difference found between the 2 anesthetics. However, the seizure-induced increase in MAP was reduced by propofol to a significantly greater degree than by etomidate.
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PMID:Etomidate versus propofol for electroconvulsive therapy in patients with schizophrenia. 1559 55

The main inhibitory neurotransmitter system in the brain, the gamma-aminobutyric acid (GABA) system, is the target for many clinically used drugs to treat, for example, anxiety disorders and epilepsy and to induce sedation and anesthesia. These drugs facilitate the function of pentameric A-type GABA (GABA(A)) receptors that are extremely widespread in the brain and composed from the repertoire of 19 subunit variants. Modern genetic studies have found associations of various subunit gene polymorphisms with neuropsychiatric disorders, including alcoholism, schizophrenia, anxiety, and bipolar affective disorder, but these studies are still at their early phase because they still have failed to lead to validated drug development targets. Recent neurobiological studies on new animal models and receptor subunit mutations have revealed novel aspects of the GABA(A) receptors, which might allow selective targeting of the drug action in receptor subtype-selective fashion, either on the synaptic or extrasynaptic receptor populations. More precisely, the greatest advances have occurred in the clarification of the molecular and behavioral mechanisms of action of the GABA(A) receptor agonists already in the clinical use, such as benzodiazepines and anesthetics, rather than in the introduction of novel compounds to clinical practice. It is likely that these new developments will help to overcome the present problems of the chronic treatment with nonselective GABA(A) agonists, that is, the development of tolerance and dependence, and to focus the drug action on the neurobiologically and neuropathologically relevant substrates.
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PMID:GABA(A) receptor subtypes as targets for neuropsychiatric drug development. 1599 46

We experienced perioperative management of a patient with schizophrenia who had been taking a large amount of antipsychotic agents until the cesarean section. A 31-year-old woman in 38th week gestation with schizophrenia underwent a cesarean section. Anesthesia was maintained with light plane of general anesthesia combined with epidural anesthesia. Perioperatively, the mother experienced no complications and the baby only developed slight generalized tremor and hypotonus for a short period after delivery.
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PMID:[Anesthetic management of a cesarean section in a patient with schizophrenia receiving a large amount of antipsychotic agents]. 1637 Mar 38

This article reviews the rapidly growing literature on the functional anatomy and behavioral correlates of the precuneus, with special reference to imaging neuroscience studies using hamodynamic techniques. The precuneus, along with adjacent areas within the posteromedial parietal cortex, is among the most active cortical regions according to the "default mode" of brain function during the conscious resting state, whereas it selectively deactivates in a number of pathophysiological conditions (ie, sleep, vegetative state, drug-induced anesthesia), and neuropsychiatric disorders (ie, epilepsy, Alzheimer's disease, and schizophrenia) characterized by impaired consciousness. These findings, along with the widespread connectivity pattern, suggest that the precuneus may play a central role in the neural network correlates of consciousness. Specifically, its activity seems to correlate with self-reflection processes, possibly involving mental imagery and episodic/autobiographical memory retrieval.
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PMID:The precuneus and consciousness. 1760 6


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