Noboru Yamaguchi

Effects of discontinuation of long-term biperiden use on cognitive function and quality of life in schizophrenia

BACKGROUND The high use of long-term antiparkinsonian anticholinergic drugs with antipsychotics has been identified as an important issue in the treatment of schizophrenia in Japan. The aim of this study was to evaluate the effects of gradual discontinuation of biperiden, an anticholinergic drug, on cognitive function and quality of life (QOL) in schizophrenia. METHODS Thirty-four schizophrenic patients who had received a second-generation antipsychotic (SGA) with concomitant biperiden for at least 3 months were enrolled. Before and 4 weeks after discontinuation of biperiden, the Japanese version of the Brief Assessment of Cognition in Schizophrenia (BACS-J) and the Schizophrenia Quality of Life Scale (SQLS-J) were administered. Clinical evaluation also included the Positive and Negative Syndrome Scale (PANSS). To compare the practice effect on BACS-J, 10 chronic patients with schizophrenia were assessed without tapering biperiden. RESULTS Biperiden was discontinued safely in most patients, and no emergent extrapyramidal symptoms were observed. Significant improvements were shown in attention, processing speed, and composite score, as measured by the BACS-J without practice effect. In addition, the psychosocial condition score on the SQLS-J and the general psychopathology score on the PANSS significantly improved after biperiden discontinuation. CONCLUSION Discontinuation of long-term biperiden use may be warranted in patients with schizophrenia treated with SGAs, as it may improve cognitive function, subjective QOL, and psychiatric symptoms with no significant adverse effects.

Profile of blonanserin for the treatment of schizophrenia

Blonanserin was developed as an antipsychotic drug in Japan and approved for the treatment of schizophrenia. It belongs to a series of 4-phenyl-2-(1-piperazinyl)pyridines and acts as an antagonist at dopamine D2, D3, and serotonin 5-HT2A receptors. Blonanserin has low affinity for 5-HT2C, adrenergic α1, histamine H1, and muscarinic M1 receptors, but displays relatively high affinity for 5-HT6 receptors. In several short-term double-blind clinical trials, blonanserin had equal efficacy as haloperidol and risperidone for positive symptoms in patients with chronic schizophrenia and was also superior to haloperidol for improving negative symptoms. Blonanserin is generally well tolerated and has a low propensity to cause metabolic side effects and prolactin elevation. We recently reported that blonanserin can improve some types of cognitive function associated with prefrontal cortical function in patients with first-episode and chronic schizophrenia. Taken together, these results suggest that blonanserin may be a promising candidate for a first-line antipsychotic for acute and maintenance therapy for schizophrenia. Further comparative studies are warranted to clarify the benefit/risk profile of blonanserin and its role in the treatment of schizophrenia.

Fluvoxamine and sigma-1 receptor agonists dehydroepiandrosterone (DHEA)-sulfate induces the Ser473-phosphorylation of Akt-1 in PC12 cells

AIMS The expression of brain-derived neurotrophic factor (BDNF) may be a downstream target of a variety of antidepressant treatments, and selective serotonin reuptake inhibitors (SSRIs) are used clinically for the treatment of depression. BDNF binds to and activates tyrosine kinases receptor (TrkB) to exert its effects. TrkB, after activation by ligands, stimulates phosphoinositide 3-kinase (PI3K). The downstream target of PI3K is Akt-1, a serine-threonine kinase. BDNF has signaling through the PLC-IP(3)/Ca(2+) pathway. Furthermore, the PLC-gamma/IP(3)/Ca(2+) pathway is regulated by the sigma-1 receptors. Here, we examined whether fluvoxamine (FLV) activated Akt-1 and increased phosphorylation of Akt-1 via sigma-1 receptor in PC12 cells. MAIN METHODS We examined the effect of the SSRI, FLV and BDNF on the phosphorylation levels of serine-threonine kinase Akt-1 in PC12 cells using immunoblotting techniques. KEY FINDINGS Treatment with 10 microM and 100 microM FLV of PC12 cells stimulated a 2.4- and 3.8-fold maximal increase in Ser(473)-phosphorylated Akt-1 levels at 40 min, respectively. Treatment with 50 ng/ml BDNF also stimulated Ser(473) -phosphorylated Akt-1 by 2.6-fold with a maximal increase at 5 min. In addition, the phosphorylation induced by FLV and BDNF was blocked by LY294002, a selective inhibitor of PI3K. The sigma-1 receptor agonists dehydroepiandrosterone (DHEA)-sulfate also stimulated a 2.1-fold increase in the level of Ser473-phosphorylated Akt-1. SIGNIFICANCE This study demonstrates that fluvoxamine treatment rapidly increased phosphorylation of Akt-1. And BDNF activated Akt-1 phosphorylation by the TrkB/PI3K/Akt-1 pathway. We conclude that the phosphorylation of Akt-1, downstream of PI3K, was the key to their antidepressant effects.

Effect of blonanserin on cognitive function in antipsychotic-naïve first-episode schizophrenia.

The purpose of this study was to evaluate the effects of blonanserin, a novel antipsychotic, on cognitive function in first‐episode schizophrenia.

Effects of tapering of long-term benzodiazepines on cognitive function in patients with schizophrenia receiving a second-generation antipsychotic.

BACKGROUND The high use of long-term benzodiazepines (BZDs) with second-generation antipsychotics (SGAs) has been identified as an important issue in the treatment of schizophrenia in Japan. The aim of this study was to evaluate the effects of gradual reduction or discontinuation of daytime BZD use on cognitive function and quality of life (QOL) in patients with chronic schizophrenia receiving an SGA. METHODS Thirty schizophrenic patients who had received an SGA with concomitant BZDs for at least 3 months were enrolled. Before and 4 weeks after tapering of daytime BZDs, the Brief Assessment of Cognition in Schizophrenia Japanese-language version (BACS-J) and the Schizophrenia Quality of Life Scale Japanese-language version (SQLS-J) were administered. Clinical evaluation also included the Positive and Negative Syndrome Scale (PANSS). To compare for practice effects on the BACS-J, 10 patients with chronic schizophrenia were assessed without tapering BZDs. RESULTS BZDs were reduced or discontinued safely in most patients, and no emergent withdrawal symptoms were observed. Significant improvements were shown in verbal memory, working memory, and composite score, as measured by the BACS-J without practice effects. In addition, the motivation/energy score on the SQLS-J, the negative symptoms and total scores on the PANSS significantly improved after tapering BZDs. CONCLUSION Reduction or discontinuation of long-term daytime use of BZDs may be warranted in patients with schizophrenia treated with SGAs, as it may improve cognitive function, subjective QOL, and psychiatric symptoms with no significant adverse effects.

Predictors of response to electroconvulsive therapy obtained using the three-factor structure of the Montgomery and Asberg Depression Rating Scale for treatment-resistant depressed patients.

Objective: Electroconvulsive therapy (ECT) is one of the most effective treatments for refractory major depressive disorder (MDD). Although studies have examined different predictors of a positive response to ECT, predictors based on symptoms listed on a depression rating scale have not been studied. Methods: This study included 24 Japanese patients who fulfilled the Diagnostic and Statistical Manual of Mental Disorders-Fourth Edition criteria for MDD or bipolar disorder with current major depressive episode. All subjects had a score of 21 or higher on the Montgomery and Åsberg Depression Rating Scale (MADRS). The 3-factor model of MADRS was used for analysis: factor 1 (dysphoria) was defined by 3 items, factor 2 (retardation) was defined by 4 items, and factor 3 (vegetative symptoms) was defined by 3 items. Electroconvulsive therapy was performed 2 times a week for a total of 6 sessions using the Thymatron System IV device (Somatics, Inc., Lake Bluff, Ill) with the brief-pulse technique. A clinical response was defined as a 50% or greater decrease on the pretreatment total MADRS score. Results: The mean factor 1 score of responders (n = 17) at pretreatment was significantly higher than that of the nonresponders (n = 7). Furthermore, a significant difference in mean factor 3 scores between responders and nonresponders was observed 1 week after the 6 ECT sessions were complete, indicating a lag in response time. No significant differences were observed in age, number of previous episodes, and duration of current episodes between the responders and nonresponders. Conclusions: This study suggests that a high factor 1 MADRS score at pretreatment was a good predictor of response to ECT in patients with treatment-resistant MDD.

Suppression of dynamin GTPase activity by sertraline leads to inhibition of dynamin-dependent endocytosis.

Dynamin (Dyn) 1 plays a role in recycling of synaptic vesicles, and thus in nervous system function. We previously showed that sertraline, a selective serotonin reuptake inhibitor (SSRI), is a mixed-type inhibitor of Dyn 1 with respect to both GTP and L-alpha-phosphatidyl-L-serine (PS) in vitro, and we suggested that it may regulate the neurotransmitter transport by modulating synaptic vesicle endocytosis via inhibition of Dyn 1 GTPase. Here, we investigated the effect of sertraline on endocytosis of marker proteins in human neuroblastoma SH-Sy5Y cells and HeLa cells. Sertraline inhibited endocytosis in both cell lines. Western blotting showed that SH-Sy5Y expresses Dyn 1 and Dyn 2, while HeLa expresses only Dyn 2. GTPase assay showed that sertraline inhibited Dyn 2 as well as Dyn 1. Therefore, the effect of sertraline on endocytosis was mediated by Dyn 2, at least in HeLa cells, as well as by Dyn 1 in cell lines that express it. Moreover, the inhibition mechanism of transferrin (Tf) uptake by sertraline differed from that in cells expressing Dyn 1 K44A, a GTP binding-defective variant, and sertraline did not interfere with the interaction between Dyn 1 and PS-liposomes.

Blonanserin, a novel atypical antipsychotic agent not actively transported as substrate by P-glycoprotein.

Although blonanserin, a novel atypical antipsychotic agent with dopamine D(2)/serotonin 5-HT(2A) antagonistic properties, displays good brain distribution, the mechanism of this distribution has not been clarified. P-glycoprotein [(P-gp) or multidrug resistance protein 1 (MDR1)] is an efflux transporter expressed in the brain and plays an important role in limiting drug entry into the central nervous system (CNS). In particular, P-gp can affect the pharmacokinetics and efficacy of antipsychotics, and exacerbate or soothe their adverse effects. In this study, we conducted in vitro and in vivo experiments to determine whether blonanserin is a P-gp substrate. Risperidone and its active metabolite 9-hydroxyrisperidone, both of which are P-gp substrates, were used as reference drugs. Affinity of blonanserin, risperidone, and 9-hydroxyrisperidone for P-gp was evaluated by in vitro transcellular transport across LLC-PK1, human MDR1 cDNA-transfected LLC-PK1 (LLC-MDR1), and mouse Mdr1a cDNA-transfected LLC-PK1 (LLC-Mdr1a). In addition, pharmacokinetic parameters in the brain and plasma (B/P ratio) of test compounds were measured in mdr1a/1b knockout (KO) and wild-type (WT) mice. The results of in vitro experiments revealed that P-gp does not actively transport blonanserin as a substrate in humans or mice. In addition, blonanserin displayed comparable B/P ratios in KO and WT mice, whereas B/P ratios of risperidone and 9-hydroxyrisperidone differed markedly in these animals. Our results indicate that blonanserin is not a P-gp substrate and therefore its brain distribution is unlikely to be affected by this transporter.

Predictors of antidepressant response to fluvoxamine obtained using the three-factor structures of the Montgomery and Åsberg Depression Rating Scale for major depressive disorders in Japanese patients

Aims:  Fluvoxamine, a selective serotonin reuptake inhibitor, is widely used to treat major depression. However, the symptomatological predictors of the response to fluvoxamine have not been studied.

Electric convulsive therapy (ECT) increases plasma and red blood cell haloperidol neuroleptic activities

In nine schizophrenic patients (five males and four females) on haloperidol treatment, plasma and red blood cell (RBC) haloperidol neuroleptic activities were measured before and after ECT by radioreceptor assay. Five patients randomly selected from these patients also served as controls on another occasion and neuroleptic activities in plasma and RBC were examined before and after the premedication only. All patients given ECT showed a considerable increase in plasma and RBC haloperidol neuroleptic activities after ECT (% increase in plasma neuroleptic activity, 28-409%; mean + SD, 136 +/- 155%, P less than 0.005, Wilcoxon test; % increase in RBC neuroleptic activity, 11-121%; mean + SD, 59 +/- 40%, P less than 0.005). However, no significant increase was observed for either plasma or RBC haloperidol neuroleptic activity, when patients were examined after premedication only. It was suggested that ECT induced a transient redistribution of haloperidol. It remains to be studied whether this phenomenon is causally related to the previous observation that the combination therapy of ECT and neuroleptics is more effective in the treatment of schizophrenia than ECT alone.