Psychopharmacology
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Randomized Controlled Trial
Pharmacological modulation of the neural basis underlying inhibition of return (IOR) in the human 5-HT2A agonist and NMDA antagonist model of psychosis.
Attentional deficits are common symptoms in schizophrenia. Recent evidence suggests that schizophrenic patients show abnormalities in spatial orienting of attention, particularly a deficit of inhibition of return (IOR). IOR is mostly thought to reflect an automatic, inhibitory mechanism protecting the organism from redirecting attention to previously scanned, insignificant locations. Pharmacologic challenges with hallucinogens have been used as models for psychosis. ⋯ The discrepancy between the behavioral and functional imaging outcome indicates that pharmacological fMRI might be a sensitive tool to detect drug-modulated blood oxygenation level-dependent signal changes in the absence of behavioral abnormalities. Our findings might help to further clarify the contradictory findings of IOR in schizophrenic patients and might, thus, shed more light on possible differential pathomechanisms of schizophrenic symptoms.
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Randomized Controlled Trial Multicenter Study Comparative Study
Efficacy and safety of bifeprunox in patients with an acute exacerbation of schizophrenia: results from a randomized, double-blind, placebo-controlled, multicenter, dose-finding study.
Bifeprunox is a partial dopamine agonist with a unique receptor-binding profile and potential antipsychotic properties. ⋯ These data suggest that 20 mg of bifeprunox may be efficacious in improving symptoms in patients with an acute exacerbation of schizophrenia. Bifeprunox appeared to be safe and well tolerated by patients in this 6-week study.
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There is important preclinical evidence of the long-lasting neurotoxic and selective effects of ecstasy (MDMA) on serotonin systems in nonhuman primates. In humans, long-term recreational use of ecstasy has been mainly associated with memory impairment. ⋯ Our findings provide evidence of mild long-term cognitive deficits among ecstasy polydrug users. Both ecstasy use and the dynamic interaction between ecstasy and cannabis effects may account for these deficits. No significant P3 alterations were found in ecstasy users.
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An endocannabinoid signaling system has not been identified in hamsters. ⋯ Endocannabinoids engage functional CB1 receptors in hamster brain to suppress anxiety-like behavior and undergo enzymatic hydrolysis catalyzed by FAAH. Our results further suggest that neither unconditioned nor conditioned social defeat in the Syrian hamster is dependent upon cannabinoid CB1 receptor activation.
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Bombesin (BB)-like peptides have been shown to affect neuroendocrine and neural functions related to the stress response and the modulation of conditioned fear. In line with this view, central administration of gastrin-releasing peptide (GRP; a mammalian analogue of BB) or its receptor antagonist (D-Tpi6, Leu13 psi[CH2NH]-Leu14) BB(6-14) (RC-3095) modulates conditioned fear. ⋯ It appears that manipulation of GRP at the BLA may influence the expression of learned fear and that these effects preferentially influence contextual versus cue-dependent emotional responses.