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)

Bipolar affective disorder and schizophrenia are severe behavioral disorders with a lifetime risk of approximately 1% in the population worldwide. There is evidence that these diseases may manifest the phenomenon of anticipation similar to that seen in diseases caused by trinucleotide repeat expansions. A recent report has implicated a potassium channel-coding gene, KCNN3, which contains a polymorphic CAG repeat in its coding region, in schizophrenia and bipolar disorder. We have tried to confirm these findings in Indian patients suffering from bipolar disorder and schizophrenia. No statistically significant evidence for the presence of an excess of longer alleles in the patient population, as compared to ethnically matched controls, was found. However, an analysis of the difference of allele sizes revealed a significantly greater number of patients with schizophrenia having differences of allele sizes > or = 5 when compared to normal controls. This finding may be of functional significance as the KCNN3 protein is thought to act as a tetramer, and a large difference in allele sizes would result in an asymmetric molecule with a different number of glutamine residues in each monomer. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:744-748, 2000.
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PMID:Association analysis of CAG repeats at the KCNN3 locus in Indian patients with bipolar disorder and schizophrenia. 1112 Nov 73

The prefrontal cortex plays a fundamental role in the working memory functions of the cerebral cortex and is also the site of dysfunction in several neurological and psychiatric disorders, including schizophrenia. Prefrontal neurons are distinguished by their capacity for sustained activity during the time a stimulus is held in memory, and this mnemonic response is considered a substrate for a variety of cognitive functions. The neuronal basis for sustained activity in prefrontal neurons is unknown but is thought to involve recurrent excitation among pyramidal neurons. Recent studies in awake behaving monkeys have demonstrated that the persistent activity in prefrontal neurons is modulated by dopamine. To examine the mechanisms by which dopamine might modulate transmission in local excitatory circuits, we have performed dual whole-cell recordings in connected pyramidal cell pairs with and without dopamine application. We find that dopamine reduces the efficacy of unitary excitatory neurotransmission in layer V pyramidal cells by decreasing its reliability. These effects, which are reproduced by a selective D1 agonist and blocked by a D1 antagonist, are independent of voltage changes and are not attenuated by blockade of sodium and potassium channels in the postsynaptic neurons. We conclude that attenuation of local horizontal excitatory synaptic transmission in layer V pyramidal neurons by dopamine is through D1 actions at a presynaptic site.
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PMID:Presynaptic regulation of recurrent excitation by D1 receptors in prefrontal circuits. 1113 20

A 33 year-old man weighting, 93 kg with schizophrenia underwent repeated electroconvulsive therapy (ECT) under general anesthesia with thiamylal 200 mg and suxamethonium 80 mg. On his fourth ECT, he developed ventricular tachycardia (VT) immediately after the treatment under general anesthesia with the same agents. The duration of VT was approximately 30 s. The VT returned to sinus rhythm without any special treatment. We speculate that light anesthesia with a small amount of thiopental associated with release of serum potassium caused by suxamethonium induced increased release of catecholamine by ECT to cause VT. After that incident, the patient underwent ECT six times under general anesthesia with thiamylal 250 mg and vecuronium 8 mg, in combination with preventive injection of magnesium sulfate 20 g without any cardiovascular complications. We conclude that the anesthetic management of patients undergoing ECT under general anesthesia should be paid a careful attention for cardiovascular instability, even if they do not have any heart diseases.
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PMID:[A case of ventricular tachycardia immediately after electroconvulsive therapy in a schinzophrenic patient]. 1121 51

There are many diseases related to ion channels. Mutations in muscle voltage-gated sodium, potassium, calcium and chloride channels, and acetylcholine-gated channel may lead to such physiological disorders as hyper- and hypokalemic periodic paralysis, myotonias, long QT syndrome, Brugada syndrome, malignant hyperthermia and myasthenia. Neuronal disorders, e.g., epilepsy, episodic ataxia, familial hemiplegic migraine, Lambert-Eaton myasthenic syndrome, Alzheimer's disease, Parkinson's disease, schizophrenia, hyperekplexia may result from dysfunction of voltage-gated sodium, potassium and calcium channels, or acetylcholine- and glycine-gated channels. Some kidney disorders, e.g., Bartter's syndrome, policystic kidney disease and Dent's disease, secretion disorders, e.g., hyperinsulinemic hypoglycemia of infancy and cystic fibrosis, vision disorders, e.g., congenital stationary night blindness and total colour-blindness may also be linked to mutations in ion channels.
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PMID:Ion channels-related diseases. 1131 Sep 70

The physiological activity of dopaminergic midbrain (DA) neurons is important for movement, cognition, and reward. Altered activity of DA neurons is a key finding in schizophrenia, but the cellular mechanisms have not been identified. Recently, KCNN3, a gene that encodes a member (SK3) of the small-conductance, calcium-activated potassium (SK) channels, has been proposed as a candidate gene for schizophrenia. However, the functional role of SK3 channels in DA neurons is unclear. We combined patch-clamp recordings with single-cell RT-PCR and confocal immunohistochemistry in mouse midbrain slices to study the function of molecularly defined SK channels in DA neurons. Biophysical and pharmacological analysis, single-cell mRNA, and protein expression profiling strongly suggest that SK3 channels mediate the calcium-dependent afterhyperpolarization in DA neurons. Perforated patch recordings of DA neurons in the substantia nigra (SN) demonstrated that SK3 channels dynamically control the frequency of spontaneous firing. In addition, SK3 channel activity was essential to maintain the high precision of the intrinsic pacemaker of DA SN neurons. In contrast, in the ventral tegmental area, DA neurons displayed significantly smaller SK currents and lower SK3 protein expression. In these DA neurons, SK3 channels were not involved in pacemaker control. Accordingly, they discharged in a more irregular manner compared with DA SN neurons. Thus, our study shows that differential SK3 channel expression is a critical molecular mechanism in DA neurons to control neuronal activity. This provides a cellular framework to understand the functional consequences of altered SK3 expression, a candidate disease mechanism for schizophrenia.
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PMID:Differential expression of the small-conductance, calcium-activated potassium channel SK3 is critical for pacemaker control in dopaminergic midbrain neurons. 1133 74

The history of pharmacotherapy of mental illness can be divided into three periods. Introduction of morphine, potassium bromide, chloral hydrate, hyoscine, paraldehyde, etc., during the second half of the 19th century (first period), led to the replacement of physical restraint by pharmacological means in behavior control. Introduction of nicotinic acid, penicillin, thiamine, etc., during the first half of the 20th century (second period), led to significant changes in the diagnostic distribution of psychiatric patients; psychoses due to cerebral pellagra, and dementia due to syphilitic general paralysis virtually disappeared from psychiatric hospitals, and the prevalence of dysmnesias markedly decreased. Treatment with therapeutically effective drugs of mania, schizophrenia, depression, bipolar disorder, generalized anxiety disorder, panic disorder, obsessive compulsive disorder, Alzheimer's disease, etc., during the second half of the 20th century (third period), brought to attention the heterogeneity of the populations within the diagnostic categories of schizophrenia and depression. Introduction of the first set of psychotropics and the spectrophotofluorimeter during the 1950s triggered the development of neuropsychopharmacology. Introduction of genetic technology for the separation of receptor subtypes in the 1980s opened the path for the "tailoring" of psychotropic drugs by the dawn of the 21st century, to receptor affinities.
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PMID:Pharmacotherapy of mental illness--a historical analysis. 1138 74

KCNN3 is a member of the gene family, KCNN1-4, encoding the small and intermediate conductance calcium-activated potassium channels. Long CAG-repeat alleles of this gene have been found to be over-represented in patients with schizophrenia in a number of population-based association studies, and this gene maps to human chromosome 1q21, a region recently implicated in schizophrenia by linkage. To set the stage for a further functional evaluation of KCNN3, we defined the nature of the genomic locus in the size, structure, and sequence of its introns and exons and the function of potential upstream regulatory regions. We isolated P1-derived artificial chromosome (PAC) clones from a genomic library and identified an overlapping available bacterial artificial chromosome (BAC) clone. Cosmids subcloned from the PAC and BAC clones were then sequenced and merged with the sequence in the public database. The KCNN3 gene spans over 163.1 kb and is composed of eight exons and seven introns. All of the exon-intron junctions conform closely to consensus splice sites. The proximal 2.5 kb of the 5'-flanking sequence was obtained and analyzed for potential transcription factor binding sites. In the proximal 2.5 kb upstream region, potential sites for the Ikaros factor (IK2), homeodomain factor Nkx-2.5/Csx (NKX25), nuclear factor of activated T-cells (NFAT), upstream stimulating factor (USF), c-AMP responsive element binding protein (CREB), POU factor Brn2 (BRN-2), myeloid zinc finger protein (MZF1), vitellogenin binding protein (VBP), HNF3 forkhead homologue 2 (HFH2), and transcription initiation were identified, as well as several potential AP-1 and AP-4 sites. Finally, a 2261-bp fragment of this upstream region was cloned into a promoterless pGL3-luciferase vector, where it produced orientation-dependent expression of the reporter gene in transiently transfected PC12 cells, cells which natively express functional KCNN3 channels, suggesting that this cloned fragment includes competent promoter elements of this gene.
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PMID:Genomic organization and promoter analysis of human KCNN3 gene. 1150 44

A 63-year-old African-American woman was admitted to the hospital with urosepsis and altered mental status. She had a history of schizophrenia and was treated with olanzapine 5 mg/day and lithium carbonate 300 mg 3 times/day. During her hospital stay, her sodium level and serum osmolality increased and her urine osmolality decreased, whereas her lithium levels remained within normal limits. Based on these findings, the patient was diagnosed with diabetes insipidus secondary to lithium therapy and was treated successfully with amiloride. Clinicians have been aware of lithium toxicity for many years and traditionally have administered thiazide diuretics for lithium-induced polyuria and nephrogenic diabetes insipidus. Recently, amiloride, a potassium-sparing diuretic, has been reported as a successful treatment for nephrogenic diabetes insipidus.
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PMID:Treatment of lithium-induced diabetes insipidus with amiloride. 1268 Apr 86

Schizophrenia and bipolar disorder both show some evidence for genetic anticipation. In addition, significant expansion of anonymous CAG repeats throughout the genome has been detected in both of these disorders. The gene KCNN3, which codes for a small/intermediate conductance, calcium-regulated potassium channel, contains a highly polymorphic CAG-repeat array in exon 1. Initial evidence for association of both schizophrenia and bipolar disorder with increased CAG-repeat length of KCNN3 has not been consistently replicated. In the present study, we performed several meta-analyses to evaluate the pooled evidence for association with CAG-repeat length of KCNN3 derived from case-control and family-based studies of both disorders. Each group of studies was analyzed under two models, including a test for direct association with repeat length, and a test for association with dichotomized repeat-length groups. No evidence for a linear relationship between disease risk and repeat length was observed, as all pooled odds ratios approximated 1.0. Results of dichotomized allele-group analyses were more variable, especially for schizophrenia, where case-control studies found a significant association with longer repeats but family-based studies implicated shorter alleles. The results of these meta-analyses demonstrate that the risks for both schizophrenia and bipolar disorder are largely, if not entirely, independent of CAG-repeat length in exon 1 of KCNN3. This study cannot exclude the possibility that some aspect of this polymorphism, such as repeat-length disparity in heterozygotes, influences risk for these disorders. Further, it remains unknown if this polymorphism, or one in linkage disequilibrium with it, contributes to some distinct feature of the disorder, such as symptom severity or anticipation.
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PMID:CAG-repeat length in exon 1 of KCNN3 does not influence risk for schizophrenia or bipolar disorder: a meta-analysis of association studies. 1289 69

The recent suggestion that secretin may be useful in treating autism and schizophrenia has begun to focus attention on the mechanisms underlying this gut-brain peptide's actions in the central nervous system (CNS). In vitro autoradiographic localization of (125)I-secretin binding sites in rat brain shows the highest binding density in the nucleus tractus solitarius (NTS). Recent evidence suggests that intravenous infusion of secretin causes fos activation in NTS, a relay station playing important roles in the central regulation of autonomic functions. In this study, whole cell patch-clamp recordings were obtained from 127 NTS neurons in rat medullary slices. The mean resting membrane potential of these neurons was -54.7 +/- 0.3 mV, the mean input resistance was 3.7 +/- 0.2 GOmega, and the action potential amplitude of these neurons was always >70 mV. Current-clamp studies showed that bath application of secretin depolarized the majority (80.8%; 42/52) of NTS neurons tested, whereas the remaining cells were either unaffected (17.3%; 9/52) or hyperpolarized (1.9%; 1/52). These depolarizing effects were maintained in the presence of 5 microM TTX and found to be concentration dependent from 10(-12) to 10(-7) M. Using voltage-clamp techniques, we also identified modulatory actions of secretin on specific ion channels. Our results demonstrate that while secretin is without effect on net whole cell potassium currents, it activates a nonselective cationic conductance (NSCC). These results show that NTS neurons are activated by secretin as a consequence of activation of a NSCC and support the emerging view that secretin can act as a neuropeptide within the CNS.
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PMID:Secretin depolarizes nucleus tractus solitarius neurons through activation of a nonselective cationic conductance. 1471 95


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