Binding of levomepromazine and cyamemazineto human recombinant dopamine receptor subtypes

Background and Objectives: Clozapine (CLOZ) and levomepromazine(LMP) improve treatment-resistant schizophrenia. The superior efficacy of CLOZ comparedwith other antipsychotic agents has been attributed to an effect on D1-like and D4receptors. We examined the binding of LMP, CLOZ and cyamemazine (CMZ), a neurolepticanalog of LMP, to human recombinant dopamine (rDA) receptor subtypes.Methods: Binding studies were performed on frozen membrane suspensions of humanrDA receptor subtypes expressed in Sf9 cells.Results: (i) LMP has a high affinity (Ki, nM) for rD2 receptor subtypes (rD2L 8.6;rD2S 4.3; rD3 8.3; rD4.2 7.9); (ii) LMP and CLOZ have comparable affinities for the rD1receptor (54.3 vs 34.6); (iii) CMZ has high affinities for rD2-like and rD1-like receptors(rD2L 4.6; rD2S 3.3; rD3 6.2; rD4.2 8.5; rD1 3.9; rD5 10.7); (iv) CMZ is 9 times more potentthan CLOZ at the rD1 receptor and 5 times more potent than CLOZ at the rD4.2 receptor;(v) CMZ has high affinities for rD1 and rD5 receptor subtypes compared withLMP and CLOZ.Conclusions: If D1 and D4 receptors are important sites for the unique action ofCLOZ, the present study points to a need for clinical trials comparing CMZ with CLOZ inschizophrenia and in particular, treatment-resistant schizophrenia, especially given therisk for agranulocytosis with CLOZ (AU)

Selective pair recognition memory impairment with no response bias in schizophrenia.

Memory is one of the cognitive functions most affected in schizophrenia, but the severity of deficits varies from one task to another. In particular, greater impairments have been reported for pair recognition than item recognition. However, decision biases and how they could affect memory dysfunction in schizophrenia have received scant attention. In this study, 26 people with schizophrenia and 28 healthy controls were administrated an association item recognition task. During encoding, participants studied pairs of visual objects, and they had to memorise objects and their pairing. In a subsequent retrieval task, participants performed an item recognition test (old/new items) and a pair recognition test (intact/rearranged pairs). Results showed that both groups were better at recognizing items than pairs, with lower performance for pair recognition, but not for item recognition, in people with schizophrenia. Analyses of response biases revealed that patients had a conservative response bias for items but not for pairs. The study also provides evidence that associative impairment may not result from decisional bias but rather from impairments in mnesic processes.

No association between the DRD3 Ser9Gly polymorphism and schizophrenia.

OBJECTIVE: To investigate the association between a Ser9Gly polymorphism of the dopamine D3 receptor gene (DRD3) and schizophrenia. METHODS: 408 schizophrenic patients and 172 control subjects were compared with regard to their DRD3 Ser9Gly genotypic and allelic frequencies. In addition, we carried out a family-based association study including 183 pedigrees (472 subjects) using the transmission disequilibrium test (TDT). RESULTS: No significant differences of genotype or homozygosity distribution were identified between patients and controls. When patients were stratified according to gender, response to treatment, age at onset, no significant differences were observed. Neither allele A (Ser), or G (Gly) were preferentially transmitted from parents to affected offspring. CONCLUSION: The hypothesis that the DRD3 Ser9Gly polymorphism plays a predisposing role in schizophrenia is not supported by this study.

Apomorphine effects on episodic memory in young healthy volunteers.

RATIONALE: Dopamine (DA) modulates working memory. However, the relation between DA systems and episodic (declarative) memory is less established. Frontal lobe DA function may be involved. We were interested in assessing whether apomorphine (Apo), a drug used extensively in clinical research as a probe of DA function, has an effect on episodic memory test performance in healthy volunteers. OBJECTIVE: To investigate the effect of a presynaptic dose of Apo on episodic memory tests and on other tests thought to be sensitive to frontal lobe functions. METHODS: Twenty healthy subjects were treated with Apo HCl (5 microg/kg sc) or placebo (10 subjects/group) in a randomized, double blind parallel group design and performance on a battery of cognitive tests was assessed. RESULTS: Apomorphine significantly impaired performance on tests of source recognition (d.f.=19, p=0.05) and item recognition memory (d.f.=19, p<0.05), and memory interference (d.f.=19, p<0.010). No significant change was found on other tests (Go/no-Go Test, Categorized Words, Stroop, Trail Making Test, and verbal fluency). CONCLUSION: Findings in this small sample of subjects suggest that dopaminergic transmission affects episodic memory functions.

Associative memory encoding and recognition in schizophrenia: an event-related fMRI study.

BACKGROUND: We used an event-related functional Magnetic Resonance Imaging (fMRI) approach to examine the neural basis of the selective associative memory deficit in schizophrenia. METHODS: Fifteen people with schizophrenia and 18 controls were scanned during a pair and item memory encoding and recognition task. During encoding, subjects studied items and pairs of visual objects. In a subsequent retrieval task, participants performed an item recognition memory test (old/new decisions) and an associative recognition test (intact/rearranged decisions). The fMRI analysis of the recognition data was restricted to correct items only and a random effects model was used. RESULTS: At the behavioral level, both groups performed equally well on item recognition, whereas people with schizophrenia demonstrated lower performance on associative recognition relative to the control group. At the brain level, the comparison between associative and item encoding revealed greater activity in the control group in the left prefrontal cortex and cingulate gyrus relative to the schizophrenia group. During recognition, greater left dorsolateral prefrontal and right inferior prefrontal activations were observed in the control group relative to the schizophrenia group. CONCLUSION: This fMRI study implicates the prefrontal cortex among other brain regions as the basis for the selective associative memory encoding and recognition deficit seen in schizophrenia.

Levomepromazine versus chlorpromazine in treatment-resistant schizophrenia: a double-blind randomized trial.

OBJECTIVE: We compared the effect of levomepromazine (LMP) with chlorpromazine (CPZ) in treatment-resistant schizophrenia (TRS). METHODS: We carried out a double-blind, parallel group study (n = 19/arm) with balanced randomization in blocks of 4 and stratification by sex. Subjects entered a 30-week trial, of which phases I-III were open: phase I (wk 0-6) baseline; phase II (wk 7-9) stepwise transition to haloperidol (HAL), 30 mg/d, plus benztropine (BT), 4 mg/d; phase III (wk 10-15) HAL, 40-60 mg/d, plus BT, 4-6 mg/d; phase IV (wk 16-20) stepwise transition to LMP or CPZ (500 mg/d) following randomization; phase V (wk 21-28) stepwise increase of LMP or CPZ (600-1000 mg/d, dose reduction permitted) to establish optimum dose; and phase VI (wk 29-30) optimized dose maintained. Criteria for TRS were based on those established by Kane et al in 1988. The criterion for a response to treatment was a reduction of 25% or more in total Brief Psychiatric Rating Scale score. RESULTS: Both LMP (p = 0.007) and CPZ (p = 0.030) improved TRS relative to baseline. Although there was no significant difference between the 2 groups in treatment response at study end point, hierarchical linear modelling of longitudinal outcome revealed a significant (p = 0.006) advantage of LMP over CPZ for the BPRS total score. Ten of 19 participants on LMP and 8 of 19 on CPZ met the criterion for treatment response, and 9 of the 18 responders did so on 200-700 mg/d phenothiazine. The mean dose of responders was 710 (standard deviation [SD] 265) mg/d (LMP) and 722 (SD 272) mg/d (CPZ). Akathisia was associated with a nonresponse to phenothiazines (p = 0.010). BPRS scores increased significantly on HAL (p = 0.006). Two of 19 participants on LMP and 5 of 19 on CPZ withdrew early from the study. CONCLUSION: LMP and CPZ may be useful in the management of TRS. A modest advantage of LMP compared with CPZ was seen in longitudinal analysis. High doses of neuroleptics may contribute to TRS; reduction of neuroleptics to modest or moderate doses should be considered before categorizing a patient as treatment resistant.

Association study of the trinucleotide repeat polymorphism within SMARCA2 and schizophrenia.

BACKGROUND: Brahma (BRM) is a key component of the multisubunit SWI/SNF complex, a complex which uses the energy of ATP hydrolysis to remodel chromatin. BRM contains an N-terminal polyglutamine domain, encoded by a polymorphic trinucleotide (CAA/CAG) repeat, the only known polymorphism in the coding region of the gene (SMARCA2). We have examined the association of this polymorphism with schizophrenia in a family-based and case/control study. SMARCA2 was chosen as a candidate gene because of its specific role in developmental pathways, its high expression level in the brain and some evidence of its association with schizophrenia spectrum disorder from genome-wide linkage analysis. RESULTS: Family-based analysis with 281 complete and incomplete triads showed that there is no significant preferential transmission of any of the alleles to the affected offspring. Also, in the case/control analysis, similar allele and genotype distributions were observed between affected cases (n = 289) and unaffected controls (n = 273) in each of three Caucasian populations studied: French Canadian, Tunisian and other Caucasians of European origin. CONCLUSION: Results from our family-based and case-control association study suggest that there is no association between the trinucleotide repeat polymorphism within SMARCA2 and schizophrenia.

Adjunctive topiramate in ultradian cycling bipolar disorder: case report with 3-year follow-up.

A patient with a treatment-refractory bipolar disorder with ultradian cycling responded to adjunctive topiramate. Response was maintained during 3-year follow-up.

Increased prevalence of schizophrenia spectrum disorders in relatives of neuroleptic-nonresponsive schizophrenic patients.

OBJECTIVE: It is suggested that schizophrenic patients who respond to neuroleptic medication and those who do not might differ with respect to their pathogenesis. In particular, it has been proposed that genetic factors may contribute to treatment response and/or outcome. In order to test this hypothesis, we compared the pattern of familial aggregation of schizophrenia related disorders in schizophrenic patients who are either responders (R) or nonresponders (NR) to typical neuroleptics. METHOD: R (n=36) or NR (n=35) patients to typical neuroleptics and healthy controls (n=63) were recruited. At least one key informant relative of each proband was interviewed blind as to the status of the proband using the Family Interview for Genetic Studies. Morbid risk for schizophrenia and cluster A personality disorders and family loading score for schizophrenia were examined in first- and second-degree relatives of these probands. RESULTS: First-degree relatives of NR patients were at a significantly higher risk for schizophrenia (MR=8.84), compared, respectively, to relatives of controls (MR=1.52) or relatives of R patients (MR=2.45). The same pattern was observed in second-degree relatives. Family loading score for schizophrenia in first- and second-degree relatives was significantly higher in NR compared to R patients. CONCLUSIONS: Schizophrenic patients who do not respond to typical neuroleptics may suffer from a more familial form of schizophrenia compared to patients who are responders.

Cognitive and clinical moderators of recognition memory in schizophrenia: a meta-analysis.

Recognition memory performance in schizophrenia has been shown to vary greatly across studies. To identify the conditions under which recognition memory is significantly impaired, we used a meta-analytic strategy to quantify the moderating effects of several cognitive and clinical variables. Eighty-four studies (from 1965 to July 2003) provided recognition memory data for both a schizophrenia and control group. The overall group comparison for recognition memory yielded a significant mean weighted effect size of d=0.76. Material specificity was the most significant cognitive variable found, with patients exhibiting greater impairment for figural than verbal recognition. A yes-no recognition format and auditory encoding also led to significantly greater effect sizes for recognition memory relative to forced-choice recognition tests and visual encoding, respectively. Furthermore, the effect size for recognition memory as measured by false alarm was smaller than the effect size as measured by hit rate or by d-prime and its related measures. Among clinical variables that were associated with higher effect sizes, chronicity was the most significant, but different trends linking poor performance to negative symptoms and general symptomatology were also observed. Thus, a recognition memory deficit moderated by both cognitive and clinical variables is clearly present in schizophrenia.

CAA insertion polymorphism in the 3'UTR of Nogo gene on 2p14 is not associated with schizophrenia.

The Nogo gene was putatively implicated in schizophrenia based on gene expression and genetic association data. In this study, we attempt to replicate the possible association of the CAA insertion and a nearby TATC deletion with schizophrenia in 204 complete and incomplete triads and in a sample of 462 unrelated cases and 153 controls, all of Caucasian origin. Our genotyping results indicated that neither the trinucleotide insertion polymorphism (CAAins; 43.4% vs. 41.8%, p>0.5) nor the polymorphism-TATC deletion (TATCdel; 49.8% vs. 49.3%, p>0.1) allele frequency is significantly different in patients compared to controls. The homozygous CAAins frequency is not significantly different between patients and controls either (18.0% vs. 15.0%, chi2=0.985, p>0.1). Furthermore, neither CAAins/TATCdel individually, nor the haplotype carrying both CAAins and TATCdel is preferentially transmitted to affected offspring.

Dopamine beta-hydroxylase (DBH) gene and schizophrenia phenotypic variability: a genetic association study.

Recently, two polymorphisms (DBH5'-Ins/del and DBH 444 g/a) of the Dopamine Beta Hydroxylase (DBH) gene were isolated, and one haplotype (Del-a) was found to be associated with low DBH activity and cocaine-induced paranoia. The purpose of this study is to test for association between these two polymorphisms and schizophrenia or its phenotypic variability with respect to neuroleptic therapeutic response and symptom profile. Allelic and haplotype distributions of these two polymorphisms were compared between two groups of schizophrenic patients (excellent neuroleptic-responders; R, n = 42 and non-responders; NR, n = 64), and one group of healthy volunteers (n = 120). The "Del" and "a" alleles were in positive linkage disequilibrium. No allelic or genotype differences in the distribution of these two polymorphisms were observed between patients and controls. However, The Del-a haplotype was significantly more common in NR patients, and the mean total BPRS score was significantly higher in the group of patients with the Del-a compared to those without the Del-a haplotype. These results suggest that the DBH gene is not a causative factor in schizophrenia but that it may be a modulator of psychotic symptoms, severity of the disorder and therapeutic response to neuroleptic drugs.

Nicotine and behavioral markers of risk for schizophrenia: a double-blind, placebo-controlled, cross-over study.

We investigated the effect of nicotine on three behavioral markers of risk for schizophrenia: sustained attention (using the Continuous Performance Task (CPT)), antisaccade performance, and smooth pursuit. Smooth pursuit was investigated in two conditions, one in which attention was enhanced (monitoring target changes) and one in which attention was not enhanced (no monitoring). Patients with schizophrenia (n = 15) and controls (n = 14) were given a 14-mg nicotine patch in a double-blind, placebo-controlled, crossover design and plasma nicotine concentrations were monitored. Nicotine concentrations were similar in both groups. A Group x Drug interaction (p <.02) on CPT hits indicated that nicotine improved sustained attention in patients but not in controls. Nicotine significantly decreased antisaccade errors (p <.01) in both groups. A Drug x Monitoring condition interaction (p <.01) on pursuit gain indicated that nicotine significantly increased pursuit gain in the no-monitoring condition in patients and controls equally, but did not improve pursuit in the monitoring condition. Thus, improvement in pursuit may have been mediated via an effect on attention rather than by an effect on oculomotor function per se. In patients, the magnitude of improvement in attention on nicotine was correlated with the improvement on eye movement tasks. Thus, nicotine improves performance on both attention and oculomotor markers of risk for schizophrenia, possibly via common mechanisms.

Neuropsychological impairments in neuroleptic-responder vs. -nonresponder schizophrenic patients and healthy volunteers.

To determine whether two groups of schizophrenic patients representing the two extremes of the neuroleptic response-spectrum (consistent responders vs. consistent nonresponders) differ with respect to their neuropsychological profile. Neuroleptic-responder (R; n=36) and -nonresponder (NR; n=39) schizophrenic patients were recruited according to a priori defined criteria of responsiveness to typical neuroleptics. Seven neuropsychological domains were assessed and compared between groups: attention-vigilance, abstraction-flexibility, spatial organization, visual-motor processing, visual memory, verbal abilities, and verbal memory and learning. All measures were standardized using the scores of 36 healthy volunteers. NR schizophrenic patients performed worse in all neuropsychological domains compared to normal controls and R schizophrenic patients. However, only performances on visual memory, verbal abilities, and verbal memory and learning were significantly poorer in NR compared to R patients. Only the latter domain significantly differentiated NR patients from the other two groups. R patients performed at an intermediate level in all domains. This report of differences in neuropsychological profile between neuroleptic-responder and -nonresponder schizophrenic patients adds to the growing evidence supporting the value of distinguishing schizophrenic patients on the basis of their therapeutic response to neuroleptics.