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Background Long-acting injectable antipsychotics (LAIs) may be a suitable therapeutic option for those patients in earlier stages of psychosis to avoid relapses and disease progression. Despite that, there is a lack of evidence in the literature regarding the use of LAIs in this profile of patients. Methods This is a retrospective cohort analysis to assess the efficacy, tolerability, and pattern of use of palmitate paliperidone long-acting injectable (PPLAI) formulations (1- and 3-month doses) compared to oral paliperidone/risperidone in patients with a nonaffective first episode of psychosis (FEP) over 12 months of follow-up. Relevant sociodemographic and clinical information were assessed, as well as main clinical scales: Positive and Negative Syndrome Scale, Personal and Social Performance Scale, and Clinical Global Impression Scale Improvement and Severity measures. Results The study included 48 patients, 16 per arm, who were aged 20–50 years and had an FEP. Significant improvements were registered for all treatment groups. Despite that, patients receiving PPLAI 1- and 3-month formulations obtained greater improvements than those in the oral group in the main domains assessed (P <.001). We found no statistically significant differences in hospitalizations between groups. Side effects were presented in 24% of patients. A trend towards reducing antipsychotic doses was observed in 43.8% of patients to achieve the minimum effective dose and avoid the occurrence of side effects. Conclusions To our knowledge, this is the first study assessing the use of palmitate paliperidone long-acting formulations versus oral risperidone or paliperidone in FEP. Treatment with PPLAI formulations seems to be an effective therapeutic choice at earlier stages of the disease. [ABSTRACT FROM AUTHOR]

Rationale: Regulator of G-protein signaling (RGS) proteins, RGS4 and RGS10, may be involved in the pathophysiology of schizophrenia. RGS4 has attracted special interest since the reports of genetic association between SNPs in RGS4 and schizophrenia. However, there is no information about the subcellular distribution of RGS4 and RGS10 proteins in psychiatric disorders. Objectives: Plasma membrane RGS4 and cytosolic RGS10 protein immunoreactivity in prefrontal cortex from schizophrenic subjects ( n = 25), non-diagnosed suicides ( n = 13), and control subjects ( n = 35), matched by age, gender, and postmortem delay, was analyzed by western blot. A second group of depressed subjects ( n = 25) and control subjects ( n = 25) was evaluated. The effect of the antipsychotic or antidepressant treatments was also assessed. Results: No significant differences in plasma membrane RGS4 and cytosolic RGS10 protein expression were observed between schizophrenic subjects, non-diagnosed suicides, and control subjects. However, RGS4 immunoreactivity was significantly higher (Δ = 33 ± 10 %, p < 0.05) in the antipsychotic-treated subgroup ( n = 12) than in the antipsychotic-free subgroup ( n = 13). Immunodensities of plasma membrane RGS4 and cytosolic RGS10 proteins did not differ between depressed and matched control subjects. Conclusions: Expression of RGS4 and RGS10 proteins at their predominant subcellular location was studied in the postmortem brain of subjects with psychiatric disorders. The results suggest unaltered membrane RGS4 and cytosolic RGS10 proteins levels in schizophrenia and major depression. Antipsychotic treatment seems to increase membrane RGS4 immunoreactivity. Further studies are needed to elucidate RGS4 and RGS10 functional status. [ABSTRACT FROM AUTHOR]

The atypical analgesic tramadol has strong structural similarities to the antidepressant venlafaxine and is a mixed noradrenaline (NA) and serotonin (5-HT) uptake inhibitor. Because tramadol has been found active in the forced swim test, a common predictor of antidepressant efficacy, we therefore examined the effects of chronic tramadol on various pre- and post-synaptic monoamine measures. Male Wistar rats (150-200 g) received tramadol (20 mg/kg i.p.) or vehicle for 21 days and were sacrificed 24 h after the last dose. Quantitative autoradiography revealed that specific frontocortical [3H]dihydroalprenolol and [3H]ketanserin binding was lower in the chronic tramadol group than controls (beta: 37+/-8 and 217+/-56 fmol/mg; 5-HT2A: 23+/-3 and 44+/-7 fmol/mg, respectively, p < 0.05). Chronic tramadol had no effect on the magnitude of electrically stimulated noradrenaline (NA) efflux or uptake in locus coeruleus (LC) slices. Although dexmedetomidine (10 nM) decreased LC NA efflux equally (by approximately 60%) in chronic tramadol and vehicle groups, desipramine (50 nM) increased LC NA efflux more in vehicle (to 164+/-7%) than tramadol-treated rats (144+/-6%; p < 0.05). Chronic tramadol had no effect on dorsal raphé (DRN) or median raphé (MRN) 5-HT efflux. However, 5-HT uptake in tramadol-treated rats was slower (p < 0.05) in MRN and nearly so (p = 0.055) in DRN. The selective 5-HT1A agonist 8-OH-DPAT reduced 5-HT efflux in both DRN and MRN. Its effect in DRN was greater in rats given chronic tramadol than in vehicle controls (54+/-2 versus 32+/-6% reduction in 5-HT efflux, respectively). In conclusion, we suggest that tramadol has many of the pre- and postsynaptic neurochemical features of a conventional antidepressant, as might be predicted from its pharmacology. [ABSTRACT FROM AUTHOR]

Peripheral administration of an amino acid load lacking tyrosine and its precursor, phenylalanine, causes a lowering of central tyrosine levels. The aim of the present study was to examine the effects of tyrosine depletion on extracellular noradrenaline using microdialysis. Extracellular noradrenaline was measured in hippocampus of the anaesthetized rat under both baseline conditions (with reuptake inhibitor, desipramine, in the perfusion medium) and following administration of the alpha2-adrenoreceptor antagonist, idazoxan. The tyrosine free amino acid load did not alter either baseline noradrenaline or the twofold rise in noradrenaline evoked by idazoxan compared with saline controls. In contrast, the catecholamine synthesis inhibitor, alpha-methyl-p-tyrosine, caused a marked reduction in baseline extracellular noradrenaline and abolished the rise induced by idazoxan. In conclusion, the present data indicate that under the conditions used, a tyrosine-free amino acid mixture may not be an effective means to interfere with central noradrenaline function. This contrasts with recent findings demonstrating that the tyrosine-depletion approach can be used to decrease presynaptic dopamine function. [ABSTRACT FROM AUTHOR]

Peripheral administration of an amino acid load lacking tyrosine and its precursor, phenylalanine, causes a lowering of central tyrosine levels. The aim of the present study was to examine the effects of tyrosine depletion on extracellular noradrenaline using microdialysis. Extracellular noradrenaline was measured in hippocampus of the anaesthetized rat under both baseline conditions (with reuptake inhibitor, desipramine, in the perfusion medium) and following administration of the a2 -adrenoreceptor antagonist, idazoxan. The tyrosine free amino acid load did not alter either baseline noradrenaline or the twofold rise in noradrenaline evoked by idazoxan compared with saline controls. In contrast, the catecholamine synthesis inhibitor, a-methyl-p-tyrosine, caused a marked reduction in baseline extracellular noradrenaline and abolished the rise induced by idazoxan. In conclusion, the present data indicate that under the conditions used, a tyrosine-free amino acid mixture may not be an effective means to interfere with central noradrenaline function. This contrasts with recent findings demonstrating that the tyrosine-depletion approach can be used to decrease presynaptic dopamine function. [ABSTRACT FROM AUTHOR]

Background: Current glioma grading schemes are limited by subjective histological criteria. Imidazoline I(2) receptors are principally expressed on glial cells.Objective: To investigate the feasibility of using the measurement of imidazoline I(2) receptor expression to differentiate glial tumours from other types of brain tumours and for grading the different gliomas.Methods: The specific binding of [(3)H]idazoxan to imidazoline I(2) receptors was measured in homogenates from human gliomas of different grades.Results: The density of imidazoline I(2) receptors was significantly greater in the three types of malignant glial tumours than in postmortem control brain or non-glial tumours. The increase in density correlated with the malignancy grade of the gliomas. No significant differences in affinity values were observed.Conclusion: These results suggest that the density of imidazoline I(2) receptors may be a useful radioligand parameter for the differentiation of glial tumours from other types of brain tumours and for grading the different gliomas. [ABSTRACT FROM AUTHOR]

Background: Current glioma grading schemes are limited by subjective histological criteria. Imidazoline I2 receptors are principally expressed on glial cells. Objective: To investigate the feasibility of using the measurement of imidazoline I2 receptor expression to differentiate glial tumours from other types of brain tumours and for grading the different gliomas. Methods: The specific binding of [³H]idazoxan to imidazoline I2 receptors was measured in homogenates from human gliomas of different grades. Results: The density of imidazoline I2 receptors was significantly greater in the three types of malignant glial tumours than in postmortem control brain or non-glial tumours. The increase in density correlated with the malignancy grade of the gliomas. No significant differences in affinity values were observed. Conclusion: These results suggest that the density of imidazoline I2 receptors may be a useful radioligand parameter for the differentiation of glial tumours from other types of brain tumours and for grading the different gliomas. [ABSTRACT FROM AUTHOR]