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

Hypothetical model based on deficient glutamatergic neurotransmission caused by hyperactive glutamate transport in astrocytes surrounding excitatory synapses in the prefrontal cortex is examined in relation to the aetiology of schizophrenia. The model is consistent with actions of neuroleptics, such as clozapine, in animal experiments and it is strongly supported by recent findings of increased expression of glutamate transporter GLT in prefrontal cortex of patients with schizophrenia. It is proposed that mechanisms regulating glutamate transport be investigated as potential targets for novel classes of neuroactive compounds with neuroleptic characteristics. Development of new efficient techniques designed specifically for the purpose of studying rapid activity-dependent translocation of glutamate transporters and associated molecules such as Na+, K+-ATPase is essential and should be encouraged.
 ...
PMID:Glutamatergic hypothesis of schizophrenia: involvement of Na+/K+-dependent glutamate transport. 1622 97

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.
 ...
PMID:Quetiapine: a review of its use in acute mania and depression associated with bipolar disorder. 1629 76

Antiepileptic drugs (AEDs) affect various neurotransmitters (i.e. GABA, glutamate), receptors (i.e. GABAergic, glutamatergic), and ion channels (i.e. for sodium or calcium) which is responsible for their anticonvulsant activity. However, this broad spectrum of action may be also utilized in other pathological conditions. For example, both conventional and newer AEDs may be used in patients suffering from neuropathic pain, migraine, essential tremor, spasticity, restless legs syndrome and a number of psychiatric disorders (f.e. bipolar disease or schizophrenia). Also, isolated data point to their potential use in Parkinson's or Alzheimer's disease. There is experimental background indicating a potent neuroprotective efficacy of AEDs in numerous models of brain ischemia. However, the clinical data are very limited and this problem requires careful assessment.
 ...
PMID:Non-epilepsy uses of antiepilepsy drugs. 1653 24

The ionotropic glutamate receptor NMDA is allosterically modulated by glycine, a coagonist, its presence is an absolute requirement for receptor activation. The transport of glycine in glutamatergic synapse is carried out by glycine transporter-1 (GlyT1), a Na+/Cl(-)-dependent carrier molecule. The primary role of GlyT1 is to maintain glycine concentrations below saturation level at postsynaptic NMDA receptors. Several isoforms of GlyT1 (a-e) have been identified, which are expressed both in glial and neuronal cell membranes. GlyT1 operates bidirectionally: it decreases synaptic glycine concentration when operates in normal mode and releases glycine from glial cells as operates in a reverse mode. It is expected that non-transportable, non-competitive inhibitors of GlyT1 may have therapeutic value in CNS disorders characterized by hypofunctional NMDA receptor-mediated glutamatergic neurotransmission. Accordingly, GlyT1 inhibitors exhibited antipsychotic profile in a number of animal tests. The first promising in vitro and in vivo experiments with glycine itself, and its N-methyl analogue, sarcosine, had initiated the syntheses of potential GlyT1 inhibitors with more complex structures, in which, however, the glycine or sarcosine moiety had always been incorporated. Those attempts led to the development of two compounds, ALX-5407 and Org-24461 with high inhibitory potency; however, none of which is now considered as a drug candidate due, most probably, to safety and/or pharmacokinetic issues. More recently, several structurally new series of highly potent inhibitors with no aminomethylcarboxy group have also been discovered. Some of them might be expected to fulfill all requirements for clinical development. The new generation of GlyT1 inhibitors may represent a novel treatment of patients suffering from schizophrenia and/or other neuropathological conditions.
 ...
PMID:Glycine transporter type-1 and its inhibitors. 1661 Oct 82

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.
 ...
PMID:Spotlight on quetiapine in acute mania and depression associated with bipolar disorder. 1669 84

Glycine has multiple neurotransmitter functions in the central nervous system (CNS). In the spinal cord and brainstem of vertebrates, it serves as a major inhibitory neurotransmitter. In addition, it participates in excitatory neurotransmission by modulating the activity of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors. The extracellular concentrations of glycine are regulated by Na+/Cl(-)-dependent glycine transporters (GlyTs), which are expressed in neurons and adjacent glial cells. Considerable progress has been made recently towards elucidating the in vivo roles of GlyTs in the CNS. The generation and analysis of animals carrying targeted disruptions of GlyT genes (GlyT knockout mice) have allowed investigators to examine the different contributions of individual GlyT subtypes to synaptic transmission. In addition, they have provided animal models for two hereditary human diseases, glycine encephalopathy and hyperekplexia. Selective GlyT inhibitors have been shown to modulate neurotransmission and might constitute promising therapeutic tools for the treatment of psychiatric and neurological disorders such as schizophrenia and pain. Therefore, pharmacological and genetic studies indicate that GlyTs are key regulators of both glycinergic inhibitory and glutamatergic excitatory neurotransmission. This chapter describes our present understanding of the functions of GlyTs and their involvement in the fine-tuning of neuronal communication.
 ...
PMID:Lessons from the knocked-out glycine transporters. 1672 46

Clozapine, an atypical antipsychotic drug effective in treatment of refractory schizophrenia causes potentially life-threatening agranulocytosis. The drug undergoes bioactivation to a toxic, chemically reactive intermediate with capacity to target stromal cells, central components of the bone marrow microenvironment implicated in neutrophil development. To identify possible mechanisms underpinning disruption of stroma as a site of drug bioactivation, toxicity was induced in vitro. Therefore metabolite generation procedures utilizing HOCl or HRP-H(2)O(2) as primary components involved in clozapine metabolism were adapted for stromal culture and coupled with viability determinations. Drug oxidation by HOCl was less toxic to stromal cells than HRP-H(2)O(2) based methods. More specifically, clozapine bioactivation by HRP-H(2)O(2) caused dose-dependent inhibition of stromal viability at therapeutically relevant concentrations. Differences in susceptibility of HAS303 and LP101 cells to the clozapine nitrenium ion were also evident. Stromal cell death was attributed to clozapine in the presence of a complete metabolising system comprising HRP and H(2)O(2). In the absence of a complete metabolising system clozapine was not cytotoxic. For LP101 cells, drug plus HRP (minus H(2)O(2)) also induced toxicity. Importantly, other antipsychotic drugs including risperidone, olanzapine and haloperidol when bioactivated, were not cytotoxic, indicating system specificity for clozapine. Exogenous GSH, N-acetylcysteine, l-ascorbic acid, catalase, and sodium azide afforded protection to cells whereas S-methylGSH, GSSG, ketoprofen and proadifen did not. Thus functional data derived from the in vitro stromal system defined in these studies may enable further investigation of the mechanisms subserving stromal impairment in clozapine-induced agranulocytosis and direct attention to improved methods for its prevention.
 ...
PMID:Clozapine bioactivation induces dose-dependent, drug-specific toxicity of human bone marrow stromal cells: a potential in vitro system for the study of agranulocytosis. 1684 94

In this article we discuss the case of a patient with schizophrenia who presented with the clinical symptoms ofcoma, fever and rigidity. Initially it was suspected that the patient had a neuroleptic malignant syndrome. Closer inspection revealed that the patient had recently used cocaine. It is known that cocaine can cause a variant of the neuroleptic malignant syndrome. The patient was treated with dantrolene sodium and bromocriptine in the Intensive Care Unit and made a complete recovery within four days.
 ...
PMID:[A cocaine-induced variant of the neuroleptic malignant syndrome. A case study]. 1695 32

Hippocampus is the brain structure, vital for episodic and declarative memory. Atrophy of the human hippocampus is seen in a variety of psychiatric and neurological disorders e.g. recurrent depression, schizophrenia, bipolar disorder, post-traumatic stress disorder, epilepsy, head injury, and Alzheimer's disease (AD). Importantly, aging hippocampus also undergoes atrophy. In many instances, for example, AD, the atrophy precedes the development of symptoms while in others, there is a temporal relationship between atrophy and symptomatology. The presence of atrophied hippocampus is one of the most consistent features of many common psychiatric disorders. Several factors contribute to this atrophy. Stress is one of the most profound factors implicated and the mechanisms involve glucocorticoids, serotonin, excitatory amino acids etc. Hippocampal formation as a whole can undergo atrophy or its individual structural components e.g. apical dendrities can exhibit atrophy. Several drugs of unrelated classes have been shown to prevent atrophy indicating heterogenous manner in which hippocampal atrophy is produced. These include, tianeptine (affects structural plasticity in hippocampus and is an effective antidepressant); phenytoin (antiseizure and neuroprotective); fluoxetine (downregulates neurodegenerative enzyme and increases neuroprotective hippocampal S100 beta); lithium (neuroprotective and antiapoptotic); tricyclic antidepressants (increase hippocampal neurogenesis); antipsychotics (reduce hippocampal neuronal suppression); sodium valproate (increases neurogenesis) and mifepristone (antioxidant, neuroprotective and anti-glucocorticoid). Now the most important question is: to what extent does the hippocampal atrophy play a role in the genesis of symptoms of diseases or their progression? And if it does, can we achieve the same degree of prevention or reversal seen in experimental animals, in humans also. An even more important question is: whether the prevention of atrophy would be clinically useful in affecting disease, viz slowing its progression, reducing morbidity, complications or positively affecting the outcome of one or more of its clinically important aspects. If the answer to this is yes, we would have to know at what stage of the disease we use the drugs, dose, duration, follow-up and efficacy. The use of these drugs in the above mentioned conditions can not only test the potential of atrophy as a future drug target, but could also help in learning more about the hippocampus in both health and diseases.
 ...
PMID:Is hippocampal atrophy a future drug target? 1828 54

Altered glutamatergic neurotransmission is considered a potential etiological factor of schizophrenia (SCZ) and affective disorders. The gene ASCT1 (SLC1A4) coding for a Na+-dependent neutral aminoacid transporter is a member of the glutamate transporter superfamily and is located on 2p13-14, a region showing linkage to both SCZ and bipolar disorder (BD). ASCT1 can thus be considered a candidate gene for both disorders. In a German sample, we tested for association between ASCT1 and both SCZ and BD. Allele and haplotype frequencies, however, did not differ between cases and controls. Recent findings on the associations between brainderived neurotrophic factor (BDNF) and SCZ and between G72/G30 and BD suggest that SCZ patients with a history of major depressive episodes (MDE) outside psychotic episodes and BD cases with a history of persecutory delusions constitute genetically distinct subgroups of these disorders. Thus, we hypothesized that restricting case definition to those 95 SCZ individuals with MDE and to those 107 BD patients with a history of persecutory delusions might clarify the relationship between BD, SCZ and ASCT1. However, these stratification approaches did not yield any significant association either. Allele and haplotype frequencies did not differ between cases and controls. Our results do not support an association of the ASCT1 gene with BD or SCZ in the German population.
 ...
PMID:No association between genetic variants at the ASCT1 gene and schizophrenia or bipolar disorder in a German sample. 1710 22


<< Previous 1 2 3 4 5 6 7 8 9 10