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Biomedical subjects

H Y Meltzer

Publications and source records attributed to H Y Meltzer.

At least 73 records · Page 4Linked to original sources
PubMed1999

The effects of clozapine, risperidone, and olanzapine on cognitive function in schizophrenia.

Cognitive function is markedly impaired in most patients with schizophrenia. Antecedents of this impairment are evident in childhood. The cognitive disability is nearly fully developed at the first episode of psychosis in most patients. The contribution of cognitive impairment to outcome in schizophrenia, especially work function, has been established. Preliminary results indicate that cognitive function, along with disorganization symptoms, discriminate schizophrenia patients who are able to work full-time from those who are not. Typical neuroleptic drugs lack the ability to improve the various domains of cognitive function impaired in schizophrenia. Atypical antipsychotic drugs pharmacologically related to clozapine-quetiapine, olanzapine, risperidone, sertindole, and ziprasidone--share the ability to produce fewer extrapyramidal symptoms than typical neuroleptic drugs and more potent antagonism of serotonin2a relative to dopamine2 receptors. However, they have a number of different clinical effects. We have identified all the studies of clozapine, olanzapine, and risperidone that provide data on their effects on cognition in schizophrenia. Data for each drug are reviewed separately in order to identify differences among them in their effects on cognition. Twelve studies that report cognitive effects of clozapine are reviewed. These studies provide (1) strong evidence that clozapine improves attention and verbal fluency and (2) moderate evidence that clozapine improves some types of executive function. However, results of the effects of clozapine on working memory and secondary verbal and spatial memory were inconclusive. Risperidone has relatively consistent positive effects on working memory, executive functioning, and attention, whereas improvement in verbal learning and memory was inconsistent. Preliminary evidence presented here suggests that olanzapine improves verbal learning and memory, verbal fluency, and executive function, but not attention, working memory, or visual learning and memory. Thus, atypical antipsychotic drugs as a group appear to be superior to typical neuroleptics with regard to cognitive function. However, available data suggest that these drugs produce significant differences in specific cognitive functions. These differences may be valuable adjunctive guides for their use in clinical practice if cognitive improvements reach clinical significance. The effects of the atypical antipsychotic drugs on cholinergic and 5-HT2a-mediated neurotransmission as the possible basis for their ability to improve cognition are discussed. It is suggested that the development of drugs for schizophrenia should focus on improving the key cognitive deficits in schizophrenia: executive function, verbal fluency, working memory, verbal and visual learning and memory, and attention.

Antipsychotic Agents↗
PubMed1999

Pindolol and mianserin augment the antidepressant activity of fluoxetine in hospitalized major depressed patients, including those with treatment resistance.

The aims of this study were to examine whether pindolol, a serotonin (5-hydroxytryptamine [5-HT])-1A receptor antagonist, and mianserin, a 5-HT2A/C and alpha2-adrenoceptor (alpha2-AR) antagonist, may augment the clinical efficacy of fluoxetine, a selective serotonin reuptake inhibitor, and shorten the latency of onset of antidepressive activity in the treatment of major and treatment-resistant depression (TRD). Ten days after admission to the hospital, 31 major depressed patients were randomly assigned using a double-blind, controlled design to receive fluoxetine 20 mg daily, fluoxetine 20 mg daily plus pindolol 7.5 mg daily, or fluoxetine 20 mg plus mianserin 30 mg daily for 5 weeks. The 17-item Hamilton Rating Scale for Depression (HAM-D) score was the primary outcome measure. Analysis of efficacy was conducted according to the intent-to-treat analysis principle considering the change from baseline to endpoint. It was found that fluoxetine plus pindolol and fluoxetine plus mianserin were significantly more effective than fluoxetine alone. Using an outcome measure of 50% reduction in the HAM-D, a 60% response rate was found in patients treated with either fluoxetine plus pindolol or fluoxetine plus mianserin compared with a 9% response rate in patients treated with fluoxetine alone. The HAM-D score 1 week after starting fluoxetine plus mianserin decreased more than 4 points and was significantly greater than that obtained by fluoxetine alone. The results suggest that pindolol and mianserin augment the efficacy of fluoxetine in the treatment of TRD and that mianserin, but not pindolol, may significantly shorten the latency of onset of antidepressive action when combined with fluoxetine.

Adult↗
PubMed1999

Placebo-controlled study of the D4/5-HT2A antagonist fananserin in the treatment of schizophrenia.

OBJECTIVE: The authors' objective was to assess the potential efficacy of fananserin (RP62203), a potent antagonist at the D4 and serotonin2A (5-HT2A) receptors, on symptoms of schizophrenia. METHOD: A double-blind, placebo-controlled study was conducted in 97 patients. Doses of fananserin reached 250 mg b.i.d. over 28 days, starting with an 8-day escalation. Most of the patients were men with paranoid schizophrenia; they were approximately 38 years old. The primary outcome measure was the total Positive and Negative Syndrome Scale score. The patients' mean score on the Positive and Negative Syndrome Scale at entry was 91.8 (SD=16.5). A low dropout rate was observed in both groups of patients (19 [30%] of those given fananserin and nine [27%] of those given placebo). RESULTS: The total Positive and Negative Syndrome Scale score of the patients given fananserin decreased at endpoint by a mean of 4.2 points (SD=15.4); the score of the patients given placebo decreased by 6.7 points (SD=19.6). No differences between treatments were found on secondary measures such as the Clinical Global Impression, Positive and Negative Syndrome Scale subscores or individual items, and Brief Psychiatric Rating Scale total score. The patients' extrapyramidal symptoms did not worsen during the trial, but the patients given fananserin had an increase in akathisia. The safety profile was good in both groups of patients. CONCLUSIONS: The results of this study do not support the prediction that a selective D4 antagonist associated with strong 5-HT2A antagonism will exhibit an antipsychotic effect.

Adolescent↗
PubMed1999

Outcome in schizophrenia: beyond symptom reduction.

Although some patients with schizophrenia may have a single episode and recover, the vast majority remain ill and unable to work for life. In the United States, patients with schizophrenia use 2.5% of the annual total health care allocations. The atypical antipsychotics, particularly when combined with psychosocial treatment, hold the promise of improving outcome and reducing the economic burden on society. Both clinical outcome and cost effectiveness are best evaluated in the context of a comprehensive assessment of a range of meaningful outcome measures studied in clinical situations. Evidence exists that the atypical antipsychotics not only reduce positive and negative symptoms and cause fewer side effects than conventional neuroleptics, but also lessen cognitive impairment, lead to a better quality of life, and have antidepressant effects, all of which should result in improved outcome in patients with schizophrenia. Increasing the availability of the atypical agents should be cost effective for society by restoring productivity in some patients with schizophrenia.

Adult↗
PubMed1999

Low-dose loxapine in the treatment of schizophrenia: is it more effective and more "atypical" than standard-dose loxapine?

Loxapine is chemically related to clozapine and shares with it and other atypical antipsychotic drugs relatively greater affinity for serotonin (5-HT)2A than for dopamine D2 receptors. However, as is the case for risperidone, the occupancy of 5-HT2A and D2 receptors can range from partial to full, depending upon the dose. It was, therefore, of interest to determine whether loxapine at low doses (< 50 mg/day) might be at least as or more effective and more tolerable than usual clinical doses (> or = 60 mg/day). We retrospectively examined data from 75 patients treated with loxapine and found psychopathology data from 10 and 12 patients treated with low-dose or standard-dose loxapine, respectively. No data were available on the other 53 patients, 28 of whom were initially treated with low-dose and 25 with standard-dose loxapine. For those treated for at least 6 weeks, there was evidence of equivalent efficacy for both low- and standard-dose loxapine with regard to improvement in Brief Psychiatric Rating Scale (BPRS) and Global Assessment Scale scores. There were 6 patients with a history of neuroleptic resistance among the 22 completers. Four of the low-dose group (40%) and 8 of the standard-dose group (67%) had at least a 20% decrease in BPRS total scores. Further study of the dose-response curve for loxapine and its usefulness in treating neuroleptic-resistant schizophrenia is indicated.

Adult↗
PubMed1999

Suicide and schizophrenia: clozapine and the InterSePT study. International Clozaril/Leponex Suicide Prevention Trial.

Suicide is one of the most serious of schizophrenic symptoms and claims the life of 9% to 13% of patients. The annual rate of suicide in schizophrenic patients is reported to be in the range of 0.4% to 0.8%, a rate that has remained constant despite the introduction of antipsychotic therapy and attendant case-management systems. The risk of suicide is not significantly different in neuroleptic-resistant or -responsive schizophrenic patients. A study of 421 schizophrenic patients reported no significant difference in the incidence of lifetime and current episodes of suicidality in treatment-resistant and -responsive patients. A number of studies with clozapine, an atypical antipsychotic, have demonstrated an 80% to 85% reduction in suicide in neuroleptic-resistant patients. This is accompanied by a decrease in depression and psychopathology and improved cognition. Clozapine's modulation of serotonergic, noradrenergic, cholinergic, and dopamine function may be the biological basis for the reduction in suicide. Weekly contact with patients, for white blood cell monitoring, has also been put forward as one explanation. To further confirm suicide risk reduction as a benefit of clozapine therapy, the International Clozaril/Leponex Suicide Prevention Trial (InterSePT) is currently being conducted. This large, prospective treatment study will compare the rate of suicide attempts and completions in schizophrenic patients at high risk of suicide randomly assigned to receive clozapine or olanzapine. The bias of weekly visits will be excluded. Results should be available in 2001.

Agranulocytosis↗
PubMed1999

R(+)-8-OH-DPAT, a serotonin(1A) receptor agonist, potentiated S(-)-sulpiride-induced dopamine release in rat medial prefrontal cortex and nucleus accumbens but not striatum.

The serotonin (5-HT)(2A/2C) receptor antagonist ritanserin has been reported to potentiate the dopamine (DA) D(2/3) receptor antagonist raclopride-induced DA release in medial prefrontal cortex (mPFC) and nucleus accumbens (NAC) but not striatum (STR). Because of reciprocal interactions between 5-HT(2A) and 5-HT(1A) receptors, we tested the hypothesis that 5-HT(1A) receptor agonism also potentiates D(2/3) receptor antagonist-induced DA release using a combination of the 5-HT(1A) receptor agonist R(+)-8-hydroxy-2-(di-n-propylamino)-tetralin [R(+)-8-OH-DPAT] and the D(2/3) receptor antagonist S(-)-sulpiride (SUL). R(+)-8-OH-DPAT (0.05 mg/kg s.c.) potentiated low but not high dose SUL (1, 3 but not 10 or 25 mg/kg s.c.)-induced DA release in NAC, but had no effect in STR at all doses tested (1, 3, 10, and 25 mg/kg s.c.). However, R(+)-8-OH-DPAT (0.05 mg/kg s.c.) alone had no effect on basal, potentiated SUL (10 and 25 mg/kg s.c.)-induced DA release in mPFC; the effect of low dose SUL (1 and 3 mg/kg s.c.) was not tested because it alone had no effect on DA release. This potentiation was abolished by pretreatment with the 5-HT(1A) receptor antagonist WAY100635 (0.05 mg/kg s.c.), which alone had no effect on DA release. These results suggest that 5-HT(1A) receptor agonism facilitates DA release in mPFC and NAC but not STR in combination with D(2) receptor antagonism.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1999

Effects of antipsychotic drugs on extracellular dopamine levels in rat medial prefrontal cortex and nucleus accumbens.

The present study was designed to compare the effects of typical and atypical antipsychotic drugs on extracellular dopamine (DA) levels in the medial prefrontal cortex (mPFC) and the nucleus accumbens (NAC), using in vivo microdialysis with dual probe implantation in awake, freely moving rats. Amperozide (2 and 10 mg/kg), clozapine (5 and 20 mg/kg), and olanzapine (10 mg/kg), all of which are atypical antipsychotics, produced greater increases in extracellular DA levels in the mPFC than in the NAC. Olanzapine (1 mg/kg), risperidone (0.1 and 1 mg/kg), also an atypical antipsychotic, and S-(-)-sulpiride (25 mg/kg), a typical antipsychotic, produced comparable increases in extracellular DA levels in the mPFC and the NAC. S-(-)-sulpiride (10 mg/kg) and haloperidol (0.1 and 1 mg/kg), another typical antipsychotic, significantly increased extracellular DA levels in the NAC but not in the mPFC. The effects of the six antipsychotic drugs to increase extracellular DA levels in the mPFC relative to those in the NAC was positively correlated with the difference between their pKi values for serotonin (5-hydroxytryptamine, 5-HT2A) and DA-D2 receptors and was inversely correlated to their pKi values for D2 or D3 receptors, but was not for 5-HT2A receptors alone. These results are consistent with the hypothesis that the ability of antipsychotic drugs to produce a greater increase in prefrontal compared with NAC extracellular DA levels may be related, in part, to weak D2 and D3 receptor affinity relative to 5-HT2A receptor antagonism.

Animals↗
PubMed1998

Differential expression of synaptosome-associated protein 25 kDa [SNAP-25] in hippocampi of neonatal mice following exposure to human influenza virus in utero.

We investigated the role of maternal exposure to human influenza virus [HI] in C57BL/6 mice on day 9 of pregnancy on the hippocampal expression of SNAP-25 in postnatal day 0 neonates, and compared them to sham-infected pups. The expression of SNAP-25 in infected neonates varied along the septotemporal axis of hippocampus and in various anatomic layers. Quantitative densitometric analysis of specific immunogold silver-enhanced SNAP-25 immunoreactivity [IR] showed increases of 40-347% over control in all septal-dorsal hippocampal layers except for the subplate layer. In mid septo-temporal hippocampus, SNAP-25 IR increased by 10-114% over control in all layers, except for the hippocampal plate, but the extent of this increase was smaller than in the dorsal-septal area. Finally,in temporal-ventral levels, SNAP-25 expression was reduced in all infected layers by 21-33% below control except for mild increases of 8.8 and 10% in subplate and hippocampal plate layers. Additionally, the infected SNAP-25 maximal density bin shifted to lower values dorsally and to higher values medially, with ventral maximal bins remaining unchanged when compared to controls. The differential expression of SNAP-25 in the hippocampi of infected neonates indicates a variable degree of vulnerability across the septo-temporal axis of hippocampus. It is surmised that while viral infection may induce excitotoxicity in the ventral hippocampus, it may cause reactive synapto-genesis in the medial and dorsal sectors of the developing brains of postnatal day 0 neonates.

Animals↗
PubMed1998

Medical-claims databases in the design of a health-outcomes comparison of quetiapine ('Seroquel') and usual-care antipsychotic medication.

Treating schizophrenia is expensive. Preventing rehospitalization of patients with schizophrenia provides an attractive opportunity for cost savings, especially for patients with 'revolving-door' or multiple-episode schizophrenia. Reducing the occurrence of extrapyramidal symptoms and other adverse events associated with standard antipsychotic agents may increase compliance and reduce the rate of rehospitalization of patients with schizophrenia. Quetiapine ('Seroquel', ICI 204,636, Zeneca Pharmaceuticals) is a new dibenzothiazepine antipsychotic agent with a low propensity for extrapyramidal symptoms. We describe here a unique methodology to compare quetiapine with usual-care medications in real-world treatment settings. The trial objective is to determine if therapy with this new atypical antipsychotic agent can reduce the rate of rehospitalization and, therefore, treatment costs. Using two secondary medical-claims databases, we defined the minimal threshold for revolving-door status as 1.0 admission per year; this definition allows our trial to focus on the subpopulation of schizophrenic patients with the greatest potential for cost savings by either the new atypical antipsychotic quetiapine or usual-care therapy. We describe here the approach used in our trial.

Adolescent↗
PubMed1998

Effect of antipsychotic drugs on extracellular serotonin levels in rat medial prefrontal cortex and nucleus accumbens.

Amperozide, clozapine, olanzapine and risperidone are more potent serotonin (5-hydroxytryptamine, 5-HT)2A receptor antagonists than dopamine D2-like receptor antagonists. Haloperidol and S(-)-sulpiride are potent or selective dopamine D2-like receptor antagonists and lack 5-HT2A receptor antagonist properties. We studied the effect of these five proven antipsychotic drugs and one putative (amperozide) antipsychotic drug on extracellular 5-HT levels in the medial prefrontal cortex and the nucleus accumbens of awake, freely-moving rats, using in vivo microdialysis with dual probe implantation. Risperidone (1 mg/kg) and clozapine (20 mg/kg) significantly increased extracellular 5-HT levels in the medial prefrontal cortex and the nucleus accumbens, respectively. Amperozide (2 and 10 mg/kg) significantly increased extracellular 5-HT levels in both regions. Olanzapine (1 and 10 mg/kg), S(-)-sulpiride (10 and 25 mg/kg), haloperidol (0.1 and 1 mg/kg) and the selective 5-HT2A receptor antagonist MDL-100,907 (1 mg/kg) had no significant effect on extracellular 5-HT levels in either region. Thus, the ability to increase extracellular 5-HT levels in the medial prefrontal cortex and the nucleus accumbens by these antipsychotic drugs is not directly related to their affinity for 5-HT2A receptors since olanzapine and MDL-100,907 had no significant effect on extracellular 5-HT levels. A variety of mechanisms other than those involving 5-HT2A receptors, e.g., reuptake inhibition (amperozide) and blockade of alpha2-adrenoceptors (clozapine), may contribute to the ability to increase extracellular 5-HT levels in the brain. The increase in extracellular 5-HT levels in the medial prefrontal cortex or nucleus accumbens following amperozide, clozapine, or risperidone administration may not be related to the effect on psychotic symptoms but could be related to effects on other types of psychopathology such as depression, negative symptoms, or cognition.

Animals↗
PubMed1998

Differential effects of chronic imipramine and fluoxetine on basal and amphetamine-induced extracellular dopamine levels in rat nucleus accumbens.

The effect of chronic treatment with the tricyclic antidepressant drug, imipramine (10 mg/kg per day), the selective serotonin (5-HT) reuptake inhibitor, fluoxetine hydrochloride (10 mg/kg per day), and vehicle, in drinking water for 24-28 days followed by 3-5 days withdrawal, on extracellular dopamine levels was studied in rat nucleus accumbens by in vivo microdialysis. Basal extracellular dopamine levels in the nucleus accumbens were increased after chronic imipramine (12.7 +/- 1.5 fmol/20 microl per 30 min, P = 0.019), and moderately decreased after chronic fluoxetine (6.5 +/- 0.6, P = 0.047), as compared to the vehicle controls (9.1 +/- 0.7), determined by one-way analysis of variance (ANOVA). Repeated measure ANOVA indicated that the D-amphetamine sulfate (0.5 mg/kg, s.c.)-induced increase in extracellular dopamine levels in the nucleus accumbens was potentiated after chronic imipramine (P = 0.002), but unchanged after chronic fluoxetine (P = 0.83). The difference in the effect of amphetamine could be influenced by the significant differences in basal levels. However, these results were also confirmed by analysis of the net area under the curve (net-AUC) for a 180-min period (six samples): for chronic imipramine (337 +/- 45 fmol/180 min, P = 0.005) and chronic fluoxetine (249 +/- 38, P = 0.57), as compared to the vehicle controls (178 +/- 29), determined by one-way ANOVA. We suggest that the effect of treatment with these agents on mesolimbic dopamine is unlikely to be involved in their shared antidepressant action, but may be relevant to other aspects of the therapeutic profile of these two drugs, e.g. the switch into mania which is more common after treatment with imipramine than fluoxetine and exacerbation of positive symptoms in patients with schizophrenia or schizoaffective disorder.

Amphetamine↗
PubMed1998

Serotonin 5-HT2C agonists selectively inhibit morphine-induced dopamine efflux in the nucleus accumbens.

In vivo microdialysis was used to compare the effects of serotonergic drugs on morphine- and cocaine-induced increases in extracellular dopamine (DA) concentrations in the rat nucleus accumbens (NAc). Systemic administration of the 5-HT2A/2C agonist, 1-(2,5-dimethoxy-4-iodophenyl)-2-aminopropane (DOI) (2.5 mg/kg, s.c. ) prevented the increase in extracellular DA in the NAc produced by morphine (5 mg/kg, i.p.). In contrast, this dose of DOI had no effect on the ability of cocaine (10 mg/kg, i.p.) to increase extracellular DA concentrations in the NAc. A 5-HT2C selective agonist, 6-chloro-2-[1-piperazinyl]-pyrazine (MK-212, 5 mg/kg, s.c.) also inhibited morphine-induced increases in extracellular DA concentrations in the NAc. Pretreatment of rats with the selective 5-HT2A antagonist, amperozide, had no effect on morphine-induced elevation of NAc DA concentrations. In order to determine if inhibition of the firing of 5-HT neurons contributes to the serotonin agonist-mediated inhibition of morphine-induced accumbens DA release, rats were pretreated with the 5-HT1A agonist, 8-OHDPAT. At a dose of 100 microg/kg (sc), 8-OHDPAT did not interfere with morphine's ability to increase DA concentrations in the NAc. These results suggest that the activation of 5-HT2C receptors selectively inhibits morphine-induced DA release in the NAc in a manner which is independent of the inhibition of 5-HT neurons.

8-Hydroxy-2-(di-n-propylamino)tetralin↗
PubMed1998

Effects of desmethylclozapine on Fos protein expression in the forebrain: in vivo biological activity of the clozapine metabolite.

Several products of the hepatic metabolism of clozapine are found in high concentrations in the plasma of schizophrenic patients treated with this atypical antipsychotic drug. One of these metabolites, N-desmethylclozapine, has substantially different affinities for dopamine and serotonin metabolites than does the parent compound. However, it is not known if this metabolite is active in vivo. We examined the effect of acute administration of desmethylclozapine to rats on forebrain Fos protein expression. Clozapine induces expression of this immediate-early gene in a distinct regional pattern in the brain. Desmethylclozapine significantly increased Fos protein expression in the medial prefrontal cortex and nucleus accumbens, but not in the dorsolateral striatum, thus mirroring the effects of the parent compound. These data indicate that the desmethyl metabolite of clozapine has in vivo biological activity.

Animals↗
PubMed1998

Serotonin subtype 2 receptor genes and clinical response to clozapine in schizophrenia patients.

Using a pharmacogenetic approach in 185 schizophrenics who have been prospectively assessed for clozapine response, we have examined the hypothesis that polymorphisms in the 5-HT2A (HTR2A), and 5-HT2C (HTR2C) genes are involved in its variable response. A-1438 A-->G polymorphism in the putative promoter and a silent T-->C 102 substitution in HTR2A were in almost complete linkage disequilibrium, and neither was associated with response (T-->C. 102 allele: chi 2 = 0.02; 1 df, p = .90; genotype: chi 2 = 0.02, 2 df, p = .99). A his452tyr HTR2A polymorphism was found to be associated with clozapine response (his452tyr allele: chi 2 = 6.43, 1 df, p = .01 [p = .04, Bonferroni corrected]; genotype: chi 2 = 6.54, 2 df, p = .04 [p = .16, Bonferroni corrected]). No HTR2A haplotype was associated with response. Interethnic differences were observed in the frequencies of the cys23ser HTR2C polymorphism. This polymorphism was not significantly associated with response in either of the ethnic groups (Caucasian and African American genotype: chi 2 = 3.46, 2 df, p = .18; chi 2 = .31, 2 df, p = .86, respectively). Although replication is required, the overall results suggest that the his452tyr HTR2A polymorphism may be involved in clozapine response.

Adult↗
PubMed1998

Selective increases in phosphoinositide signaling activity and G protein levels in postmortem brain from subjects with schizophrenia or alcohol dependence.

Comparisons of the activity of the G protein-mediated phosphoinositide signal transduction system and of G protein levels were made in two regions of frontal cortex from eight schizophrenic, alcohol-dependent, and control subjects. G protein-mediated phosphoinositide hydrolysis was measured by stimulating cortical membranes incubated with [3H]phosphatidylinositol with 0.3-10 microM guanosine 5'-O-(3-thio)triphosphate (GTPgammaS). In frontal cortex areas 8/9, GTPgammaS-induced phosphoinositide hydrolysis was 50% greater in schizophrenic than control or alcohol-dependent subjects, whereas there were no differences among these groups of subjects in the response to GTPgammaS in frontal cortex area 10. Agonists for dopaminergic, cholinergic, purinergic, serotonergic, histaminergic, and glutamatergic receptors coupled to the phosphoinositide signaling system increased [3H]phosphatidylinositol hydrolysis in a GTPgammaS-dependent manner. Responses to most agonists were similar in all three subject groups in both cortical regions, with the largest difference being a 40% greater response to dopaminergic receptor stimulation in frontal cortex 8/9 from schizophrenic subjects. Measurements of the levels of phospholipase C-beta, and of alpha-subunits of Gq, Go, Gi1, Gi2, and Gs, made by immunoblot analyses revealed no differences among the groups of subjects except for increased G alpha(o) in schizophrenic subjects and increased G alpha(o) and G alpha(i1) in alcohol-dependent subjects. These results demonstrate that schizophrenia is associated with increased activity of the phosphoinositide signal transduction system and increased levels of G alpha(o), whereas the phosphoinositide system was unaltered in alcohol dependence, but G alpha(o) and G alpha(i1) were increased.

Adult↗