Biomedical subjects

Kenji Hashimoto

Publications and source records attributed to Kenji Hashimoto.

At least 91 records · Page 5Linked to original sources

PubMed2004

[Major depressive disorders and BDNF (brain-derived neurotrophic factor)].

We reviewed the pre-clinical and clinical papers demonstrating that BDNF plays a role in the pathophysiology of major depressive disorders. Experimental studies suggest that BDNF expression is induced by chronic antidepressant treatments, and that BDNF itself have antidepressant activity in animal models of depression. Furthermore, BDNF may protect neurons against stress-induced damage, and affect neurogenesis in the adult hippocampus. Our clinical study showed that serum levels of BDNF in drug naive patients with depression were significantly decreased as compared with normal controls. These findings suggest that low BDNF levels may play a pivotal role in the pathophysiology of major depression. It is unclear whether low BDNF levels are primary or secondary in patients with depression. One hypothesis would be that reduced BDNF might reflect a genetic vulnerability in patients with depression. Another possible explanation would be that stress-induced BDNF reductions might cause neuronal damage, which would in turn lead to acquired biological vulnerability. In order to determine the precise mechanism underlying the relationship between reduced BDNF levels and the etiology of major depression under both genetic and environmental backgrounds, further detailed study will be necessary.

Animals↗

PubMed2003

Acute and chronic administration of the selective 5-HT1A receptor antagonist WAY-405 significantly alters the activity of midbrain dopamine neurons in rats: an in vivo electrophysiological study.

In this study, we examined the effect of the acute and chronic administration of WAY-405, a selective 5-HT(1A) receptor antagonist, on the number and firing pattern of spontaneously active substantia nigra pars compacta (A9) and ventral tegmental area (A10) dopamine (DA) neurons in anesthetized rats. This was accomplished using in vivo, extracellular single unit recording. The i.v. administration of WAY-405 (5-640 microg/kg) did not significantly alter the basal firing rate or pattern of spontaneously active A9 and A10 DA neurons. A single injection of 10 microg/kg of WAY-405 decreased the number of spontaneously active A10 DA neurons and the 100 microg/kg dose significantly decreased the number of spontaneously active A9 and A10 DA neurons compared to vehicle-treated animals. A single injection of 1, 10, or 100 microg/kg of WAY-405 significantly decreased the degree of bursting of A10 DA neurons. In contrast, 1 microg/kg i.p. of WAY-405 significantly increased the percent of A9 DA neurons exhibiting a bursting pattern. The repeated administration of 10 or 100 microg/kg i.p. of WAY-405 (21 days) significantly decreased the number of spontaneously active DA neurons in both the A9 and A10 compared to vehicle-treated animals and this decrease was not reversed by i.v. (+)-apomorphine. The repeated administration of WAY-405 significantly altered the firing pattern of DA neurons, particularly those in the A10 area. Overall, these results indicate that the antagonism of the 5-HT(1A) receptor significantly alters the activity of midbrain DA neurons in anesthetized rats.

Action Potentials↗

PubMed2003

Protective effect of LY379268, a selective group II metabotropic glutamate receptor agonist, on dizocilpine-induced neuropathological changes in rat retrosplenial cortex.

In the present study, we examined the effects of LY379268, the group II metabotropic glutamate receptor (mGluR) agonist, on the neuropathological changes in the rat retrosplenial cortex induced by noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine ((+)-MK-801). Administration of LY379268 (1, 3, 10 mg/kg, i.p.) reduced dizocilpine (0.5 mg/kg, i.p.)-induced neuropathological changes in the retrosplenial cortex, in a dose-dependent manner. Co-administration of LY379268 (10 mg/kg, i.p.) with group II mGluR antagonist LY341495 (5 mg/kg, i.p.) blocked the effects of LY379268. Furthermore, LY379268 (10 mg/kg, i.p.) significantly reduced the expression of heat shock protein HSP-70, a marker of reversible neuronal injury, in the rat retrosplenial cortex after administration of dizocilpine (0.5 mg/kg, i.p.). Moreover, pretreatment with LY379268 (10 mg/kg, i.p.) significantly suppressed the increase in extracellular acetylcholine (ACh) levels in the retrosplenial cortex induced by administration of dizocilpine (0.5 mg/kg, i.p.). These results suggest that LY379268 has a protective effect on the neurotoxicity in the rat retrosplenial cortex after administration of NMDA receptor antagonists such as dizocilpine.

Acetylcholine↗

PubMed2003

Serum brain-derived neurotrophic factor (BDNF) levels in schizophrenia are indistinguishable from controls.

Our previous study showed that serum brain-derived neurotrophic factor (BDNF) was significantly decreased in the antidepressant-naive patients with major depressive disorders. However, it was still unclear whether serum BDNF level was altered in drug-naive patients with schizophrenia. Using ELISA, we measured serum BDNF levels in antipsychotic-naive (n=15) and medicated (n=25) patients with schizophrenia, and in age- and sex-matched normal controls (n=40). There were no significant differences in serum BDNF levels among antipsychotic-naive (n=15) and medicated (n=25) patients and normal controls (n=40). Possible factors such as duration of illness, age of onset, Brief Psychiatric Rating Scale scores, and chlorpromazine equivalent dosages of antipsychotics did not reveal any significant correlations with BDNF levels. Our results do not support the view that serum BDNF levels are associated with schizophrenia.

Adult↗

PubMed2003

Increased levels of serum basic fibroblast growth factor in schizophrenia.

Basic fibroblast growth factor (bFGF) is a multifunctional growth factor that has been implicated in a variety of neurodevelopmental processes. The aim of the present study was to examine whether bFGF contributes to the pathophysiology of schizophrenia. Serum bFGF levels in 40 patients with schizophrenia (15 drug-naive and 25 medicated patients) and in 40 age- and sex-matched healthy normal controls were measured. Serum bFGF levels were significantly higher in the medicated patients than in the normal controls. Analysis of partial correlation coefficients showed that the increased bFGF levels might not be attributable to antipsychotic medication. Although there was no significant overall difference in bFGF levels between drug-naive patients and normal controls, the bFGF levels in these patients significantly correlated with the severity of negative symptoms. Furthermore, we found a significant negative correlation between serum bFGF levels and the age of onset in the entire patient group. Our finding of elevated bFGF levels in the serum of patients with schizophrenia, especially in earlier age-of-onset cases considered to have more neurodevelopmental insults, suggests that bFGF abnormalities may be involved in the pathophysiology of schizophrenia.

Adult↗

PubMed2003

Decreased levels of serum brain-derived neurotrophic factor in female patients with eating disorders.

BACKGROUND: Several lines of evidence suggest that brain-derived neurotrophic factor (BDNF) plays a role in the regulation of eating behavior. Because of its role in eating behavior, which is especially relevant to eating disorders, BDNF is an attractive candidate for investigation of potential biological markers of eating disorders such as bulimia nervosa (BN) and anorexia nervosa (AN). METHODS: We enrolled 18 female patients with BN, 12 female patients with AN, and 21 age-matched female normal control subjects in this study. Eating-related psychopathology and depressive symptoms were evaluated using the Bulimic Investigatory Test, Edinburgh (BITE) and the Hamilton Depression Rating Scale (HDRS). Serum BDNF levels were measured by a sandwich enzyme-linked immunosorbent assay. RESULTS: Serum levels of BDNF in the patients with AN or BN were significantly (p<.0001) decreased compared with those of normal control subjects, and serum BDNF levels in the patients with AN were significantly (p=.027) lower than those in patients with BN. A significant positive correlation (r=.378, p=.006) between serum BDNF levels and body mass index in all of the subjects was detected. Furthermore, there was a significant positive correlation (r=.435, p=.015) between the BITE symptom scale score and HDRS in these patients. CONCLUSIONS: The present study suggests that BDNF may play a role in the pathophysiology of eating disorders.

Adolescent↗

PubMed2003

Alterations of serum levels of brain-derived neurotrophic factor (BDNF) in depressed patients with or without antidepressants.

BACKGROUND: Because researchers have reported that antidepressants increase the expression of brain-derived neurotrophic factor (BDNF) in the rat hippocampus, we investigated whether serum BDNF levels may be used as a putative biological marker for major depressive disorders (MDD). METHODS: We measured serum BDNF in the following three groups: antidepressant-naive patients with MDD (n = 16), antidepressant-treated patients with MDD (n = 17), and normal control subjects (n = 50). Patients were evaluated using the Hamilton Rating Scale for Depression (HAM-D). Serum BDNF was assayed with the sandwich ELISA method. RESULTS: We found that serum BDNF was significantly lower in the antidepressant-naive group (mean, 17.6 ng/mL; SD, 9.6) than in the treated (mean, 30.6 ng/mL; SD, 12.3; p =.001) or in the control group (mean, 27.7 ng/mL; SD, 11.4; p =.002). There was a significant negative correlation (r = -.350, z = -2.003, p =.045) between serum BDNF and HAM-D scores in all patients. In a preliminary examination, reduced BDNF values of three drug-naive patients recovered to basal levels after antidepressant treatment. CONCLUSIONS: Our study suggests that low BDNF levels may play a pivotal role in the pathophysiology of MDD and that antidepressants may increase BDNF in depressed patients.

Adult↗

PubMed2003

Two clusters of serum midkine levels in drug-naive patients with schizophrenia.

Midkine (MK) is a heparin-binding growth factor implicated in various biological phenomena such as development of the hippocampus and anxiety. We evaluated serum MK levels of drug-naive (n=15) and medicated (n=25) patients with schizophrenia, and age- and sex-matched normal controls (n=38). The patients showed two clusters in the levels. Four drug-naive patients (26.7%) and two medicated patients (8.0%) had abnormally high values, but no controls did, there being a significant difference in the numbers (P=0.003, Fisher's exact test). Furthermore, in other patients, the mean MK levels in drug-naive schizophrenia (0.30+/-0.10 ng/ml) were significantly (P=0.018, Fisher's protected least significant difference test) decreased than those in the controls (0.40+/-0.12 ng/ml). These suggest that there are two clusters of serum MK abnormalities in drug-naive patients with schizophrenia.

Adult↗

PubMed2003

Protective effect of the antipsychotic drug zotepine on dizocilpine-induced neuropathological changes in rat retrosplenial cortex.

An atypical antipsychotic drug, zotepine, which is pharmacologically and clinically related to clozapine, has unique therapeutic effects on patients with schizophrenia. It has been demonstrated that clozapine blocks neurotoxicity in the rat retrosplenial cortex induced by administration of the noncompetitive N-methyl-D-aspartate (NMDA) receptor antagonist dizocilpine ((+)-MK-801). We examined whether or not zotepine has the ability to block neurotoxicity in the rat retrosplenial cortex induced by administration of dizocilpine. Female Sprague-Dawley rats were injected intraperitoneally (i.p.) with vehicle (1 mg/kg), zotepine (5, 10 or 20 mg/kg) or clozapine (20 mg/kg). Fifteen minutes later, animals were injected intraperitoneally (i.p.) with vehicle (1 ml/kg) or dizocilpine (0.5 mg/kg). Neuropathological changes (neuronal vacuolization) were assessed 4 h after administration of dizocilpine. Immunohistochemical analysis of heat shock protein HSP-70, a marker of reversible neuronal injury, was performed 24 h after administration of dizocilpine. The pretreatment with zotepine (5, 10 or 20 mg/kg) significantly decreased the number of vacuolized neurons in the rat retrosplenial cortex 4 h after the administration of dizocilpine (0.5 mg/kg), in a dose-dependent manner. The potency of zotepine (20 mg/kg) for dizocilpine-induced neurotoxicity was similar to that of clozapine (20 mg/kg). Furthermore, similar to the case with clozapine (20 mg/kg, i.p.), zotepine (20 mg/kg, i.p.) significantly attenuated the expression of HSP-70 in the rat retrosplenial cortex induced by dizocilpine (0.5 mg/kg, i.p.). The present study suggests that the neuroprotective effects of zotepine- on dizocilpine-induced neurotoxicity are equipotent to those of clozapine. Based on the NMDA receptor hypofunction hypothesis of schizophrenia, the efficacy of zotepine in this study may partly contribute to the unique therapeutic effects of zotepine in patients with schizophrenia.

Animals↗

PubMed2003

Decreased serum levels of D-serine in patients with schizophrenia: evidence in support of the N-methyl-D-aspartate receptor hypofunction hypothesis of schizophrenia.

BACKGROUND: The hypofunction of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors has been implicated in the pathophysiology of schizophrenia. Several lines of evidence suggest that D-serine may function as an endogenous agonist of the glycine site of the NMDA receptor. The aim of this study was to examine whether serum levels of D- and L-serine in patients with schizophrenia are different from those of healthy controls. METHODS: Forty-two patients with schizophrenia and 42 age- and sex-matched healthy controls were enrolled in this study. Symptoms were assessed using the Brief Psychiatric Rating Scale. Serum levels of total serine and D- and L-serine were measured by high-performance liquid chromatography. RESULTS: Serum levels of D-serine in the patients with schizophrenia were significantly (z = -3.30, P =.001) lower than those of healthy controls. In contrast, serum levels of total (D and L) serine (z = -2.40, P =.02) and L-serine (z = -2.49, P =.01) in the schizophrenic patients were significantly higher than those of controls. In addition, the percentage of D-serine in the total serine in the schizophrenic patients was significantly (z = -4.78, P<.001) lower than that of controls, suggesting that the activity of serine racemase, an enzyme catalyzing the formation of D-serine from L-serine, may have been reduced in the schizophrenic patients. CONCLUSIONS: Reduced levels of D-serine may play a role in the pathophysiology of schizophrenia, and serum D- and L-serine levels might provide a measurable biological marker for schizophrenia.

Adolescent↗

PubMed2003

Malignant fibrous histiocytoma of scalp with intracranial invasion 20 years after postoperative irradiation.

We report a case of malignant fibrous histiocytoma with intracranial invasion occurring 20 years after radiation therapy for astrocytoma. Magnetic resonance imaging suggested that a dumbbell-shaped tumor arising from soft tissue was pressing the brain. Histopathological findings revealed a storiform pattern with spindle cells such as fibroblasts, histiocytes, epithelioid cells with irregularly shaped nuclei, and bizarre giant cells. Three operations involving craniectomy were necessary because of recurrence.

Adult↗

PubMed2003

Secretion of saliva in X-irradiated rat submandibular glands.

The mechanism of radiation-induced dysfunction in rat submandibular glands was investigated at the cellular level. After X irradiation (single dose, 15 Gy), a vacuolation in the acinar cells or an enlargement of the acinar lumen was observed as a typical morphological change for 2 weeks. As observed using a video-enhanced contrast differential interference contrast (VEC-DIC) microscope, exocytosis and shrinkage of the acinar cells induced by application of pilocarpine (100 microM) were markedly suppressed for 5 days and then recovered to 80% of the control levels. Using an immunohistochemical method, no significant change was observed in amylase distribution, but a marked loss of aquaporin 5 was found in the acinar cells after the irradiation. The extent and time course of pilocarpine-induced mobilization of intracellular Ca(2+) did not change after the irradiation. We conclude that radiation-induced dysfunction in the salivary glands is due to an impairment of exocytosis and a reduction of water secretion. The loss of aquaporin 5 and possibly other membrane-fusion proteins in acinar cells may be the major mechanism underlying such a dysfunction.

Amylases↗

PubMed2002

Effect of acute and chronic administration of the selective 5-HT2C receptor antagonist SB-243213 on midbrain dopamine neurons in the rat: an in vivo extracellular single cell study.

In this study, we examined the effect of the acute and chronic administration of the selective 5-HT2C receptor antagonist SB-243213 (SB) on the activity of spontaneously active dopamine (DA) cells in the substantia nigra pars compacta (SNC) and ventral tegmental area (VTA) in anesthetized, albino, male Sprague-Dawley rats. This was accomplished using the technique of in vivo extracellular single cell recording. The acute i.v. administration of SB-243213 (0.025-3.2 mg/kg) did not significantly alter the basal firing rate or pattern of either spontaneously active SNC or VTA DA neurons compared to vehicle-treated controls. The acute i.p. administration of either 1 or 10 mg/kg of SB-243213 did not significantly alter the number of spontaneously active DA cells in the SNC or VTA compared to vehicle-treated controls, whereas the 3 mg/kg dose only significantly decreased the number of spontaneously active VTA DA neurons. Overall, the 1 mg/kg dose of SB-243213 did not significantly alter the firing pattern of either SNC or VTA DA neurons compared to vehicle-treated controls. In contrast, the 3 mg/kg dose significantly altered the firing pattern of SNC DA neurons, whereas the 10 mg/kg dose altered the firing pattern of DA neurons in both the SNC and VTA. The repeated i.p. administration (21 days) of 1, 3, and 10 mg/kg of SB-243213 or 20 mg/kg of clozapine produced a significant decrease in the number of spontaneously active DA cells in the VTA compared to vehicle-treated controls. The decrease in the number of spontaneously active VTA DA cells was not reversed by the i.v. administration of (+)-apomorphine (50 microg/kg). The repeated administration of either 1 or 3 mg/kg of SB-243213 had minimal effects on the firing pattern of either SNC or VTA DA neurons. In contrast, the firing pattern of VTA DA neurons was significantly altered by 10 mg/kg dose of SB-243213. Overall, our results indicate that antagonism of the 5-HT2C receptor alters the activity of midbrain DA neurons in anesthetized rats and suggest that SB-243213 has an atypical antipsychotic profile following chronic administration.

2-Hydroxypropyl-beta-cyclodextrin↗

PubMed2002

Induction of NMDA and GABAA receptor-mediated Ca2+ oscillations with KCC2 mRNA downregulation in injured facial motoneurons.

To clarify the changes that occur in gamma-aminobutyric acid type A (GABA(A)) receptor-mediated effects and contribute to alterations in the network activities after neuronal injury, we studied intracellular Ca(2+) concentration ([Ca(2+)](i)) dynamics in a rat facial-nerve-transection model. In facial motoneurons, an elevation of the resting [Ca(2+)](i), GABA-mediated [Ca(2+)](i) transients, enhancement of the glutamate-evoked [Ca(2+)](i) increases, and spontaneous [Ca(2+)](i) oscillations were induced by axotomy. All these axotomy-induced modifications were abolished by the GABA(A)-receptor antagonist bicuculline and N-methyl-d-aspartate (NMDA)-receptor antagonist d(-)-2-amino-5-phosphonopentanoic acid. A downregulation of K(+)-Cl(-) cotransporter (KCC2) mRNA, an increase in intracellular Cl(-) concentration ([Cl(-)](i)), and transformation of GABAergic hyperpolarization to depolarization were also induced by axotomy. We suggest that in axotomized neurons KCC2 downregulation impairs Cl(-) homeostasis and makes GABA act depolarizing, resulting in endogenous GABA inducing [Ca(2+)](i) oscillations via facilitation of NMDA-receptor activation. Such GABA(A)-receptor-mediated [Ca(2+)](i) oscillations may play a role in neural survival and regeneration.

Animals↗

PubMed2002

Correlation of plasma neurosteroid levels to the severity of negative symptoms in male patients with schizophrenia.

The authors examined the correlations among plasma levels of ACTH, cortisol, progesterone, testosterone, and dehydroepiandrosterone sulfate (DHEA-S) and their relationship with the scales for assessment of negative symptoms (SANS) in the male schizophrenic patients with negative symptoms. The subjects were 28 male schizophrenic patients categorized as with low negative symptoms (N = 14) and with moderate negative symptoms (N = 14) and 13 healthy subjects. Plasma levels of neurosteroids were measured by radioimmunoassay. Significant correlations of SANS scores with plasma levels of ACTH, cortisol and testosterone, but not progesterone and DHEA-S, were found in the male schizophrenic patients. Furthermore, plasma levels of ACTH, cortisol, and testosterone in the male schizophrenic patients with moderate negative symptoms, but not low negative symptoms, were significantly different from normal controls. The measurements of plasma neurosteroid levels could be a useful biological marker for the severity of negative symptoms in schizophrenic patients.

Adrenocorticotropic Hormone↗

PubMed2002

Comparative evaluation of two serotonin transporter ligands in the human brain: [(11)C](+)McN5652 and [(11)C]cyanoimipramine.

Serotonin (5-HT) is considered to be an important transmitter underlying mood and behaviour. Abnormalities of the 5-HT transporter have been suggested in mood disorders, since it is one of the major binding sites of antidepressants. A number of ligands have been developed to visualise the 5-HT transporter in vivo, but only a few have successfully visualised specific binding in vivo. In this study, we comparatively evaluated two ligands for 5-HT transporter, [(11)C](+)McN5652 and [(11)C]cyanoimipramine, in the human brain. Brain uptake of [(11)C](+)McN5652 and [(11)C]cyanoimipramine was measured with PET in 15 healthy volunteers. Second PET scans were performed after pretreatment with the potent 5-HT reuptake inhibitor clomipramine. Data were analysed as regional brain uptake as well as whole brain uptake. In six healthy volunteers uptake of the two ligands was also measured in the lung since it is one of the high-uptake organs in the body. In the brain, high accumulation was observed in the thalamus and striatum, the regions known to contain high densities of 5-HT transporter, for both [(11)C](+)McN5652 and [(11)C]cyanoimipramine. The average ratio of thalamus to cerebellum uptake at 90 min after the tracer injection was approximately 1.6 for [(11)C](+)McN5652 and 1.7 for [(11)C]cyanoimipramine, while the ratios obtained after pretreatment with clomipramine were approximately 1.2. However, the whole brain uptake of [(11)C](+)McN5652 was approximately twice that of [(11)C]cyanoimipramine, while the lung uptake of [(11)C](+)McN5652 was approximately half that of [(11)C]cyanoimipramine. Both [(11)C](+)McN5652 and [(11)C]cyanoimipramine showed sufficient specific binding for performance of a quantitative analysis in the brain. [(11)C](+)McN5652 could be superior because of its higher distribution to the brain.

Adult↗

PubMed2002

Roles of endogenous glutathione levels on 6-hydroxydopamine-induced apoptotic neuronal cell death in human neuroblastoma SK-N-SH cells.

We investigated the roles of endogenous glutathione on 6-hydroxydopamine (6-OHDA)-induced apoptosis in human neuroblastoma SK-N-SH cells using DNA fragmentation enzyme-immunoassay and the DNA dye Hoechst 33258 staining. We observed that exogenous reduced glutathione (GSH), but not oxidized glutathione (GSSG), protected 6-OHDA (25 micro M)-induced apoptosis in a dose-dependent manner. Preincubation (18 h) with the glutathione synthesis inhibitor DL-buthionine-(S,R)-sulfoximine (BSO) significantly potentiated the toxic effects of 6-OHDA (12.5 or 25 micro M). In contrast to BSO, N-acetylcysteine (NAC) blocked, and L-(-)-cystine, the glutathione precursor, significantly attenuated 6-OHDA (25 micro M)-induced apoptosis, respectively. No alterations in endogenous glutathione concentrations were detected at 5, 15, 30, 60 min, 1 hour, 3 hours, or 6 hours after 6-OHDA (25 micro M) treatment. However, we found a 3.5-fold increase of intracellular glutathione levels 24 hours later. On the contrary, higher concentration (100 micro M) of 6-OHDA treatment, which caused more severe cell death, showed no changes of glutathione levels. These results suggest that delayed induction of endogenous glutathione might play an important role in the neuroprotective mechanism against dopamine cell death. In addition, we found that NAC might work as a beneficial catecholaminergic neuron-survival factor more efficiently than exogenous glutathione or L-cystine.

Acetylcysteine↗

PubMed2002

Neuropharmacological profile of a novel potential atypical antipsychotic drug Y-931 (8-fluoro-12-(4-methylpiperazin-1-yl)- 6H-[1]benzothieno[2,3-b][1,5] benzodiazepine maleate).

The neuropharmacological profile of Y-931, 8-fluoro-12- (4-methylpiperazin-1-yl)- 6H-[1]benzothieno [2,3-b][1,5]benzodiazepine maleate, was investigated in comparison with those of typical and claimed atypical antipsychotic drugs. Similar to clozapine and olanzapine, Y-931 interacted with multiple neurotransmitter receptors such as dopaminergic, serotonergic, alpha-adrenergic, muscarinic and histaminergic receptors. Y-931, as well as the other antipsychotics, was active in a dose-dependent manner in established tests which are indicative of potential antipsychotic activity such as inhibition of apomorphine-induced hyperactivity and suppression of conditioned avoidance responses, however, only Y-931 and clozapine were devoid of cataleptogenic potential. In models of N-methyl-D-aspartate (NMDA) receptor hypofunction, Y-931 demonstrated the most potent protective action against the dizocilpine-induced neurotoxicity (neuronal vacuolization) in the rat retrosplenial cortex ([Y-931 (ED(50); 0.20 mg/kg, p.o.), olanzapine (1.1), clozapine (5.7), risperidone (6.9), haloperidol (19)). Furthermore, Y-931 and clozapine, unlike the other antipsychotics used, reversed the dizocilpine-induced social deficits at the same doses at which their neuroprotective action was exhibited. The present results suggest that Y-931 may be a novel potential atypical antipsychotic drug with a low risk of extrapyramidal syndrome (EPS) and the property to ameliorate NMDA receptor hypofunction.

Animals↗