European Neuropsychopharmacology (v.20, #10)

Contents (OBC).

The economic impact of depression: Resistance or severity? by L. Fostick; A. Silberman; M. Beckman; B. Spivak; D. Amital (671-675).
Treatment-Resistant Depression (TRD) affects 60 to 70% of patients with Major Depressive Disorder (MDD). The economic impact of depression in general, and of TRD specifically, was found to be relatively high. As the course of depression can be defined both by the severity of the disease and by the resistance to treatment, the question of the unique contribution of MDD severity vs. resistance to the economic burden of depression is being raised. One hundred and seven unipolar MDD patients, all treated for at least 4 weeks, were enrolled in the study. Patients were assessed for their current MDD severity using the Hamilton Depression Rating Scale (HDRS) and past treatments, and for medical-related costs (number of blood and imaging tests, visits paid to physicians, psychiatric hospitalizations) and incapacity-related costs (number of working days lost) during the last episode. TRD and non-TRD patients were, respectively, 39.3% and 60.7% of the patients recruited for the study. TRD patients had more severe depression, and higher costs for imaging tests, physician visits, psychiatric hospitalizations, and number of working days lost. In addition, higher MDD severity was found to be associated with higher costs. Finally, when controlling for the shared variance of TRD and MDD severity, by using residual scores, TRD was associated with higher costs, but MDD severity was no longer related to costs. While both resistance and severity are associated with higher direct and indirect costs, our findings suggest that TRD may be the main factor in determining the economic burden of depression.
Keywords: Major Depressive Disorder (MDD); Treatment-Resistant Depression (TRD); Severity; Economic burden;

This study was designed to investigate the structural differences in the brains of first episode, drug-naïve patients with major depressive disorder and panic disorder versus healthy control subjects. High-resolution brain magnetic resonance images were performed on patients and health control subjects (age, sex and handedness matched). Structural magnetic resonance images of brain were estimated by optimized voxel-based morphometry of FSL (FMRIB Software Library). Patients had deficits of gray matter volumes over right anterior cingulate cortex, right medial frontal gyrus, left posterior cingulate cortex, right parahippocampal gyrus, limbic areas, occipital lingual gyrus and bilateral cerebellums when compared to controls. These results suggested that this group of patients has possible deficits of gray matter volumes over the default-mode network, fronto-cingulate and limbic structures. The decline of gray matter volumes might have started since the first episode.
Keywords: First episode; Major depressive disorder; Panic disorder; Gray matter; Default-mode network; Limbic;

Levodopa and 3-OMD levels in Parkinson patients treated with Duodopa by A. Antonini; G. Bondiolotti; F. Natuzzi; S.R. Bareggi (683-687).
We studied 19 patients (14 men, 5 women, Hoehn and Yahr (H&Y) ≥ 3) with advanced Parkinson's disease (PD) attending the Parkinson Institute, Milan, whose motor fluctuations and dyskinesia were not controlled by oral medications. After all oral PD medications had been withdrawn, they received a duodenal levodopa infusions (Duodopa, Solvay Pharmaceuticals) for 14 h/day through a transabdominal port; levodopa boluses were administered in the morning and during “off” periods. The patients were evaluated by means of the UPDRS in the morning (“off”) and 60–120 min after the infusion (“on”) at baseline and for a mean follow-up of 13.5 ± 12.5 months (up to 36 months in 10 patients:). Levodopa (l-DOPA) and its metabolites were determined by HPLC with electrochemical detection. l-DOPA concentrations tended to higher in the afternoon (2008 ± 345 vs 1713 ± 274 ng/mL) and correlated with the daily dose. O-methyldopa (OMD) levels correlated with l-DOPA levels, and the OMD/l-DOPA ratios were stable over the day. There was a relationship between decreasing UPDRS III scores and decreasing OMD/l-DOPA ratios. Dyskinesia (UPDRS IV, items 32–34) showed a clear improvement over time but there was no clear relationship with l-DOPA and OMD levels, or the OMD/l-DOPA ratio. The l-DOPA/dose ratio was stable over time, whereas OMD levels and the OMD/l-DOPA ratio decreased. It is conceivable that continuous infusion decreases metabolism possibly due to a reduction in methyl donor availability, as demonstrated by the increase in total homocysteine levels. Our results do not support the development of tolerance even after several months of continuous infusion, and indicate that pharmacodynamic factors play a role in afternoon off periods.
Keywords: Duodopa; Levodopa levels; OMD levels; Dyskinesia;

Association study of the GSK-3B gene with tardive dyskinesia in European Caucasians by Renan P. Souza; Gary Remington; Nabilah I. Chowdhury; Matthew K. Lau; Aristotle N. Voineskos; Jeffrey A. Lieberman; Herbert Y. Meltzer; James L. Kennedy (688-694).
There is solid evidence of a genetic predisposition to tardive dyskinesia (TD) although the pathophysiological mechanisms of TD are still unclear. Nevertheless, the dopamine overactivity hypothesis of the TD etiology receives support from both pharmacological and physiological evidence. Dopaminergic signaling modulates the glycogen synthase kinase 3B (GSK-3B), a kinase that may play a critical role in the pathogenesis of neurodegenerative diseases. GSK-3B is an essential element of the apoptotic signaling cascade induced by oxidative stress, which may be involved in TD pathogenesis. We investigated whether GSK-3B polymorphisms (rs11919783, rs6805251, rs7624540, rs6438552, rs4072520, rs9878473, rs6779828 and rs3755557) selected using tagging method were associated with TD manifestation and abnormal involuntary movement severity. We evaluated 215 schizophrenia subjects from whom 169 were European Caucasians. All eight evaluated variants had their minor allele carriers consistently showing lower risk to TD and lower Abnormal Involuntary Movement Scale. The rs6805251, rs6438552 and rs9878473 variants showed a trend for association with TD in European Caucasian subjects (permuted p  = 0.07). Furthermore, all tested markers showed p  ≤ 0.0007 after we incorporated age as covariate in the analysis of the abnormal involuntary movement severity. Our results suggest that GSK-3B polymorphism may play a role in the genetic vulnerability to TD manifestation in schizophrenia subjects with European Caucasian background further implicating polymorphisms in the dopamine D2-like receptor signaling in this context. These findings should be read with caution particularly before independent replication.
Keywords: AIMS; Glycogen synthase kinase; Movement disorders; Extrapyramidal symptoms; Pharmacogenetics; Genetics;

Acute quetiapine dose-dependently exacerbates anhedonia induced by withdrawal from escalating doses of d-amphetamine by Simon Zhornitsky; Stéphane Potvin; Emmanuel Stip; Pierre-Paul Rompré (695-703).
Recent clinical studies show that the atypical antipsychotic medication, quetiapine, may be beneficial in the treatment of substance abuse by alleviating the withdrawal-negative affect stage of addiction. Since the effect of quetiapine on central reward function is largely unknown we studied its effects on brain stimulation reward in animals under withdrawal from escalating doses of d-amphetamine. Male Sprague–Dawley rats were trained to produce an operant response to receive a short train of electrical stimulation to the lateral hypothalamus. Measures of reward threshold were determined with the curve-shift method in different groups of rats before, and during four days after treatment with escalating doses (1 to 10 mg/kg, i.p.) of d-amphetamine or its vehicle. At 24 h of withdrawal, the effects of two doses of quetiapine (2 and 10 mg/kg i.p.) were tested. Animals treated with d-amphetamine showed a 25% reward deficit at 24 h of withdrawal, an effect that decreased progressively over the next three days. Quetiapine attenuated reward in the vehicle-control animals, and amplified the anhedonia at the moderate, but not the low, dose in the animals under withdrawal. These results show that acute treatment with clinically relevant doses of quetiapine for the treatment of schizophrenia may exacerbate anhedonia induced by amphetamine withdrawal. Further research should investigate whether repeated treatment with quetiapine has the ability to reverse amphetamine withdrawal-induced anhedonia.
Keywords: Anhedonia; Amphetamine; Dopamine; Quetiapine; Reward; Tolerance;

The β3 adrenoceptor agonist, amibegron (SR58611A) counteracts stress-induced behavioral and neurochemical changes by Alessandra Tamburella; Vincenzo Micale; Gian Marco Leggio; Filippo Drago (704-713).
These experiments were made to study the mechanisms underlying the antidepressant-like effects of the β3 adrenoceptor agonist amibegron (SR58611A). To this purpose, the expression levels of the hippocampal cyclic adenosine monophosphate (cAMP)-response element binding protein (CREB), brain-derived neurotrophic factor (BDNF), B-cell lymphoma-2 (Bcl-2) and Bax proteins were assessed, by using western blot analysis, in rats tested in the forced swim test (FST). Under basal conditions (no previous exposure to stressors), different groups of male Wistar rats received acutely or repeatedly (once/day for 7 days) intraperitoneal (i.p.) injections of amibegron (1, 5 and 10 mg/kg), the tricyclic antidepressant (TCA) clomipramine (50 mg/kg), the selective serotonin reuptake inhibitor (SSRI) citalopram (15 mg/kg) or their vehicles. The influence of stress-related conditions was studied in rats subjected to acute (4 h) or repeated (4 h/day for 7 days) restraint stress, applied prior to the FST procedure. Compared to the control groups, both stressor procedures increased the immobility time in the FST and reduced hippocampal BDNF and Bcl-2/Bax ratio proteins expression, which were counteracted by amibegron (5 and 10 mg/kg) treatment. Opposite effects were found in the CREB expression, since it was lower after acute and higher after repeated stress procedure, respectively. Again, these effects were reversed by amibegron treatment. Different results were obtained in animals treated with clomipramine or citalopram. Hence, it is likely that the observed behavioral effects of amibegron could be due, at least in part, to its action on hippocampal expression of neurotrophic and/or anti-apoptotic factors, supporting the hypothesis that β3 adrenoceptors may be a therapeutic target for the treatment of stress-related disorders.
Keywords: β3 adrenoceptors; Restraint stress; Neurotrophic factors; Forced swim test; Amibegron;

Dysregulations in monoaminergic systems have been implicated in attention deficit/hyperactivity disorder. The spontaneous hypertensive rats (SHR) are used as an animal model for ADHD. Juvenile SHR rats exhibited low dopamine transporter (DAT) density, low vesicular monoamine transporter 2 (VMAT2) density and lower unstimulated dopamine (DA) release in comparison to their corresponding WKY controls. Chronic methylphenidate treatment of the young SHR rats was associated with lower DAT density and lower unstimulated basal dopamine release but with enhanced potassium- and amphetamine-induced dopamine release. These neurochemical alterations might be relevant to the pathophysiology and to the beneficial effect of methylphenidate in ADHD.
Keywords: Attention deficit hyperactivity disorder (ADHD); Spontaneous hypertensive rats (SHR); Wistar Kyoto rats (WKY); Dopamine transporter (DAT); Vesicular monoamine transporter 2 (VMAT2); Methylphenidate (MPH);

Reduced platelet G protein-coupled receptor kinase 2 in major depressive disorder: Antidepressant treatment-induced upregulation of GRK2 protein discriminates between responder and non-responder patients by Jesús A. García-Sevilla; María Álvaro-Bartolomé; Rebeca Díez-Alarcia; Alfredo Ramos-Miguel; Dolors Puigdemont; Víctor Pérez; Enric Alvarez; J. Javier Meana (721-730).
The homologous regulation of neurotransmitter receptors by G protein-coupled receptor kinases (GRKs) is important in the pathogenesis and treatment of major depressive disorder (MDD). Previous studies have reported that the basal status of GRK2 is different in brains (upregulation) and platelets (downregulation) of subjects with MDD. The principal aim of this study was to re-examine the status of platelet membrane GRK2 protein in patients with MDD, along with GRK3 (a close kinase homolog) and GRK5 (a kinase with different properties), before and after treatment with serotonin-selective reuptake inhibitor (SSRI) or serotonin noradrenaline reuptake inhibitor (SNRI) antidepressants. The main findings indicated that platelet GRK2 and p-Ser670 GRK2 were reduced (36–41%) in unmedicated MDD subjects, and that GRK2 content correlated inversely with the severity of depression (r  = − 0.51). Effective antidepressant treatments normalized platelet GRK2, and, notably, GRK2 upregulation discriminated between responder and non-responder patients. Other findings revealed a modest reduction of platelet GRK3 (23%) and no alteration of platelet GRK5 content. In untreated subjects with MDD, lymphocyte GRK2 and GRK5 mRNAs were unaltered but antidepressant treatment-induced upregulation of GRK2 mRNA expression. The reduced content of platelet GRK2 protein is a relevant target in MDD. Although this peripheral GRK2 defect does not mirror the canonical regulation of brain GRK2 in depressed suicides, it could well represent a disease state marker as well as a surrogate of response to effective antidepressant treatment.
Keywords: Major depressive disorder; Platelet GRK2/3/5 proteins; Lymphocyte GRK2/5 mRNAs; SSRIs; SNRIs;

Based on phenomenological similarities between anhedonia (reward deficits) associated with drug withdrawal and the negative symptoms of schizophrenia, we showed previously that the atypical antipsychotic clozapine attenuated reward deficits associated with psychostimulant withdrawal. Antagonism of α2 adrenergic and 5-HT2A receptors may contribute to these effects of clozapine. We investigated here whether blockade of α2 or 5-HT2A receptors by idazoxan and M100907, respectively, would reverse anhedonic aspects of psychostimulant withdrawal. Idazoxan treatment facilitated recovery from spontaneous nicotine, but not amphetamine, withdrawal by attenuating reward deficits and increase the number of somatic signs. Thus, α2 adrenoceptor blockade may have beneficial effects against nicotine withdrawal and may be involved in the effects of clozapine previously observed. M100907 worsened the anhedonia associated with nicotine and amphetamine withdrawal, suggesting that monotherapy with M100907 may exacerbate the expression of the negative symptoms of schizophrenia or nicotine withdrawal symptoms in people, including schizophrenia patients, attempting to quit smoking.
Keywords: DHβE; Brain reward thresholds; Somatic signs of withdrawal; Anhedonia;