Preliminary data from a 4-year mirror-image and multicentre study of patients initiating paliperidone palmitate 6-monthly long-acting injectable antipsychotic: the Paliperidone 2 per Year study.

Background: Paliperidone palmitate 6-monthly (PP6M) is the first long-acting antipsychotic injectable (LAI) to allow for only two medication administrations per year, though there is presently limited insight into its effectiveness and potential added value in real clinical practice conditions. Objectives: To present our ongoing study and draw its preliminary data on patient characteristics initiating PP6M and adherence during the first year of treatment. Methods: The paliperidone 2 per year (P2Y) study is a 4-year, multicentre, prospective mirror-image pragmatic study taking place at over 20 different sites in Europe. The mirror period covers 2 years either side of the PP6M LAI initiation. Retrospective data for the previous 2 years are collected for each patient from the electronic health records. Prospective data are recorded at baseline, 6, 12, 18 and 24 months of drug administration and also cover information on concomitant psychiatric medication, relapses, hospital admissions, side effects, discontinuation and its reasons. Meanwhile, here we present preliminary data from the P2Y study at basal and 6-month period (first and second PP6M administration). Results: At the point of PP6M initiation, the most frequent diagnosis was schizophrenia (69%), the clinical global impression scale mean score was 3.5 (moderately markedly ill) and the rate of previous hospital admissions per patient and year was 0.21. PP6M was initiated after a median of 3-4 years on previous treatment: 146 (73%) from paliperidone palmitate 3-monthly, 37 (19%) from paliperidone palmitate 1-monthly and 17 (9%) from other antipsychotics. The mean dose of the first PP6M was 1098.9 mg. The retention rate at 6 months and 1 year of treatment on PP6M in our cohort was 94%. Conclusion: Patient and clinician preference for LAIs with longer dosing intervals was the main reason for PP6M initiation/switching resulting in high treatment persistence. Future data are needed to evaluate the full impact of PP6M in clinical practice.

External Validation of SAFE Score to Predict Atrial Fibrillation Diagnosis after Ischemic Stroke: A Retrospective Multicenter Study.

Introduction: The screening for atrial fibrillation (AF) scale (SAFE score) was recently developed to provide a prediction of the diagnosis of AF after an ischemic stroke. It includes 7 items: age ≥ 65 years, bronchopathy, thyroid disease, cortical location of stroke, intracranial large vessel occlusion, NT-ProBNP ≥250 pg/mL, and left atrial enlargement. In the internal validation, a good performance was obtained, with an AUC = 0.88 (95% CI 0.84-0.91) and sensitivity and specificity of 83% and 80%, respectively, for scores ≥ 5. The aim of this study is the external validation of the SAFE score in a multicenter cohort. Methods: A retrospective multicenter study, including consecutive patients with ischemic stroke or transient ischemic attack between 2020 and 2022 with at least 24 hours of cardiac monitoring. Patients with previous AF or AF diagnosed on admission ECG were excluded. Results: Overall, 395 patients were recruited for analysis. The SAFE score obtained an AUC = 0.822 (95% CI 0.778-0.866) with a sensitivity of 87.2%, a specificity of 65.4%, a positive predictive value of 44.1%, and a negative predictive value of 94.3% for a SAFE score ≥ 5, with no significant gender differences. Calibration analysis in the external cohort showed an absence of significant differences between the observed values and those predicted by the model (Hosmer-Lemeshow's test 0.089). Conclusions: The SAFE score showed adequate discriminative ability and calibration, so its external validation is justified. Further validations in other external cohorts or specific subpopulations of stroke patients might be required.

Cumulative Clinical Experience of the Use of Paliperidone Palmitate 3-Monthly Long-Acting Injection in the Treatment of Schizophrenia: A Critical Appraisal.

Paliperidone palmitate 3-monthly (PP3M), an approved maintenance treatment for patients with schizophrenia, was the first long-acting antipsychotic injectable (LAI) to require only four administrations per year. Here, we aimed to review the available evidence about its use in the management of schizophrenia to date and highlight key study findings in order to provide a balanced overview of current experience in clinical practice. For that purpose, an extensive search of available literature from PubMed, Embase, and Web of Science was conducted in March 2023. Emerging data from real-world studies appear to signal that the benefits of the use of PP3M may well extent beyond the obvious convenience for patients and resource efficiency for services and may be actually associated with improved effectiveness and patient satisfaction. Large naturalistic studies from Australia, Europe and the US comparing treatment continuation between newer LAIs and/or oral antipsychotics showed that patients treated with PP3M had higher compliance rates and a longer period of continuous use. The risk of relapse, re-hospitalization and number of bed days was also lower with PP3M compared to PP1M and other LAIs as demonstrated by several cohort studies. Furthermore, patients treated with PP3M were using lower doses of benzodiazepines and concomitant oral antipsychotics compared with other LAIs. What is more, PP3M appears to positively impact patients' satisfaction and quality of life, facilitating long-term goals. In fact, recent studies recorded better quality-adjusted life years and decreased stigma, with improved social acceptability and promotion of rehabilitation for patients transitioning to PP3M. The rates of general satisfaction rates with PP3M were also higher among psychiatrists and caregivers who reported overall less concerns. In conclusion, clinical exposure and a growing body of evidence thus far, reinforce the use of PP3M in an effort to enhance patient outcomes alongside individual experience and treatment persistence.

Upregulation of Heat-Shock Protein (hsp)-27 in a Patient with Heterozygous SPG11 c.1951C>T and SYNJ1 c.2614G>T Mutations Causing Clinical Spastic Paraplegia.

We report a 49-year-old patient suffering from spastic paraplegia with a novel heterozygous mutation and analyzed the levels of heat shock proteins (hsp)-27, dopamine (DA), and its metabolites in their cerebrospinal fluid (CSF). The hsp27 protein concentration in the patient's CSF was assayed by an ELISA kit, while DA levels and its metabolites in the CSF, 3,4-dihydroxyphenylacetic acid (DOPAC), Cys-DA, and Cys-DOPA were measured by HPLC. Whole exome sequencing demonstrated SPG-11 c.1951C>T and novel SYNJ1 c.2614G>T mutations, both heterozygous recessive. The patient's DA and DOPAC levels in their CSF were significantly decreased (53.0 ± 6.92 and 473.3 ± 72.19, p < 0.05, respectively) while no differences were found in their Cys-DA. Nonetheless, Cys-DA/DOPAC ratio (0.213 ± 0.024, p < 0.05) and hsp27 levels (1073.0 ± 136.4, p < 0.05) were significantly higher. To the best of our knowledge, the c.2614G>T SYNJ1 mutation has not been previously reported. Our patient does not produce fully functional spatacsin and synaptojanin-1 proteins. In this line, our results showed decreased DA and DOPAC levels in the patient's CSF, indicating loss of DAergic neurons. Many factors have been described as being responsible for the increased cys-DA/DOPAC ratio, such as MAO inhibition and decreased antioxidant activity in DAergic neurons which would increase catecholquinones and consequently cysteinyl-catechols. In conclusion, haploinsufficiency of spatacsin and synaptojanin-1 proteins might be the underlying cause of neurodegeneration produced by protein trafficking defects, DA vesicle trafficking/recycling processes, autophagy dysfunction, and cell death leading to hsp27 upregulation as a cellular mechanism of protection and/or to balance impaired protein trafficking.

Case report: Endovascular embolization of a cerebral pseudoaneurysm caused by SARS-CoV2 infection.

Background: Severe COVID-19 has been shown to produce convulsions, encephalitis, Guillain-Barré syndrome, or cerebrovascular disease. However, only 4 case reports described subarachnoid or brain hemorrhage caused by ruptured cerebral aneurysms or pseudoaneurysms in patients with COVID-19. Cerebral pseudoaneurysms represent <1% of all intracranial aneurysms and have been related to radiation therapy, vasculitis, rupture of true saccular aneurysms, arteriovenous malformations, and infections by bacteria and viruses, such as Epstein-Bar and Herpes virus. Case presentation: A 28-year-old Caucasian woman, with no medical history of interest and completely vaccinated against SARS-CoV-2, was admitted to Neurology due to progressive tetraparesis with areflexia, a cough, and a fever of 38°C. SARS-CoV2 PCR was positive while lumbar puncture, blood tests, and electromyogram showed criteria for Guillain-Barré syndrome. Despite the treatment, the patient developed dyspnea and tetraplegia requiring invasive mechanical ventilation. There was motor neurological improvement but a decreased level of consciousness was observed on day 13. A brain CT scan demonstrated an acute haematoma and cerebral arteriography showed a 4-mm pseudoaneurysm located in a branch of the left middle cerebral artery. Given the high risk of rebleeding, endovascular treatment was decided upon. Therefore, complete embolization of the pseudoaneurysm was carried out by using the synthetic glue N-butyl-cyanocrylate. Two days later, the patient was clinically and neurologically recovered and was discharged. Lastly, a new angiography showed no evidence of the pseudoaneurysm 3-weeks later. Conclusions: We report, for the first time, a patient suffering a severe immune reaction caused by SARS-CoV2 infection and developing a cerebral pseudoaneurysm treated with endovascular embolization without complications.

Case Report: Identification of a Heterozygous XPA c.553C>T Mutation Causing Neurological Impairment in a Case of Xeroderma Pigmentosum Complementation Group A.

We aimed to determine if an adolescent patient presenting with neurological impairment has xeroderma pigmentosum (XP). For this purpose, whole-exome sequencing was performed to assess mutations in XP genes. Dermal fibroblasts were established from a skin biopsy and XPA expression determined by immunoblotting. Nucleotide excision repair (NER) capacity was measured by detection of unscheduled DNA synthesis (UDS) in UVC-irradiated patient fibroblasts. Genetic analysis revealed two recessive mutations in XPA, one known c.682C>T, p.Arg228Ter, and the other c.553C>T, p.Gln185Ter, only two cases were reported. XPA protein was virtually undetectable in lysates from patient-derived fibroblast. The patient had significantly lower UV-induced UDS (3.03 ± 1.95%, p < 0.0001) compared with healthy controls (C5RO = 100 ± 12.2; C1UMN = 118 ± 5.87), indicating significant NER impairment. In conclusion, measurement of NER capacity is beneficial for the diagnosis of XP and in understanding the functional impact of novel mutations in XP genes. Our findings highlight the importance of neurologists considering XP in their differential diagnosis when evaluating patients with atypical neurodegeneration.

Evaluation of Risk Factors Associated to Prescription of Benzodiazepines and its Patterns in a Cohort of Patients from Mental Health: A Real World Study in Spain.

Purpose: we aimed 1) to evaluate the risk factors associated to the benzodiazepines intake; 2) to assess the impact about the use of long acting injectables antipsychotics (LAIs); 3) to assess the risk in severe and affective disorders and 4) to identify the prescription patterns of use in mental health in a cohort of patients from Spain. Methods: 735 outpatients from Mental Health were included. Demographic and clinical data were collected. In order to compare the use of benzodiazepines we calculated the daily dose equivalents (mg/day) to diazepam as standard. Results: The most commonly prescribed benzodiazepine was clonazepam (33%) and the mean daily dose of diazepam equivalents was 24.9 mg. It was higher in affective disorders (40.35 ± 3.36) and lower in patients using LAIs antipsychotics (17.50 ± 1.39; p = 0.001). Multivariate analysis showed that to be women (OR = 1.559, 95% CI = 1.059-2.295, p = 0.024), the use of drugs (OR = 1.671, 95% CI = 1.127-2.477, p = 0.011) and suffering any affective disorder (OR = 1.542, 95% CI = 1.355-1.826, p = 0.040) increased the risk of benzodiazepine intake. In contrast, the use of LAIs antipsychotics significantly reduced it versus oral antipsychotics (OR = 5.226, 95% CI = 3.185-8.575, p = 0.001). Conclusions: benzodiazepines are widely prescribed, mainly clonazepam followed by lorazepam and diazepam. Most of patients used at least one benzodiazepine and the mean daily intake was 25 mg diazepam equivalents. Therefore, benzodiazepines are extensively prescribed and used at higher doses than desirable. These, findings could be useful for clinicians and their practice.

Off-label use of second-generation antipsychotics in borderline personality disorder: a comparative real-world study among oral and long-acting injectables in Spain.

The aim of the present study was to evaluate the use of oral vs. long-acting injectables (LAIs) antipsychotics, as well as, to compare the effectiveness of different LAI antipsychotics [aripiprazole-1-month, paliperidone-1-month (PP1M), paliperidone-3-month (PP3M) and risperidone long-acting injectable (RLAI)] in patients diagnosed with borderline personality disorder (BPD), by evaluating the following clinical outcomes: (1) the number of hospital admissions; (2) the number of documented suicidal behaviour/attempts; and (3) the use of concomitant treatments, including benzodiazepines, oral antipsychotics and biperiden. We included a total of 116 patients diagnosed with BPD and treated with antipsychotic medication: 50 using a LAI antipsychotic formulation and 66 using the equivalent main oral antipsychotic. Patients treated with LAIs showed a decreased ratio of visits to emergency compared with the oral treatment group, and between LAIs, PP3M vs. aripiprazole-1-month group. Furthermore, patients treated with LAIs used lower number and dose of concomitant antipsychotics compared with patients treated with oral antipsychotics. Moreover, PP1M and PP3M used lower daily dose of diazepam equivalents compared with the aripiprazole-1-month and RLAI treatment groups. In conclusion, the use of LAIs may play a role in the management of BPD.

Evaluation of long-acting injectable antipsychotics with the corresponding oral formulation in a cohort of patients with schizophrenia: a real-world study in Spain.

To date, only a few studies compared some long-acting injectables (LAIs) antipsychotics showing similar symptom improvement, relapse rates and adherence to treatment. We evaluated the use of LAIs antipsychotics [aripiprazole-1-month (A1M); paliperidone-1-month and 3-month (PP1M and PP3M) and biweekly (2w)-LAIs] and their corresponding oral formulations through (1) the number of hospital re-admissions, (2) the number of documented suicidal behaviour/attempts and (3) the use of concomitant benzodiazepines, oral antipsychotics and biperiden. A total of 277 patients, ≥18 years old, were included if were treated with the corresponding oral or LAI antipsychotic during at least 12 months and were previously diagnosed with schizophrenia. Our results showed that LAIs associated significantly lower suicidal behaviour, reduced the number of hospital admissions, lower diazepam and haloperidol equivalents and mean daily dose of biperiden intake versus oral antipsychotics. Furthermore, significant differences were found between LAIs. Specifically, PP3M was associated to lower hospital admissions versus A1M; PP1M and PP3M lower doses of diazepam equivalents versus 2w-LAIs and finally, PP1M lower antipsychotic intake versus 2w-LAIs. In conclusion, LAIs improved clinical outcomes by reducing the need for concomitant treatments and hospital admissions over oral antipsychotics. PP1M and PP3M showed better outcomes versus A1M and biweekly LAIs.

Long-Acting Injectable Antipsychotics: Analysis of Prescription Patterns and Patient Characteristics in Mental Health from a Spanish Real-World Study.

BACKGROUND AND OBJECTIVE: Long-acting injectable antipsychotics (LAIs) have been widely studied in schizophrenia and evidence suggests that they could be also used for the treatment of bipolar and schizoaffective disorders. Nonetheless, there are no studies evaluating their role in other psychiatric disorders. We aimed to evaluate the use of the newest monthly and 3-monthly LAIs-aripiprazole once monthly, paliperidone 1- and 3-monthly (PP1M, PP3M)-against the 2-weekly LAIs, using the following clinical outcomes: (1) the number of hospital re-admissions, (2) the number of documented suicidal behaviors/attempts, and (3) the use of concomitant treatments, including benzodiazepines, oral antipsychotics, and biperiden. METHODS: A total of 431 patients were included who were treated with the corresponding LAI over at least 12 months and were previously diagnosed with a psychiatric disorder. Statistical analyses were performed using an ANCOVA model, Student's t test, and the Pearson's r test. RESULTS: Our results showed significantly decreased re-admissions using PP3M versus the bi-weekly LAIs and aripiprazole once monthly, while no significant differences were found in suicidal behavior. Furthermore, we found a significantly lower intake of benzodiazepines in PP1M and PP3M groups versus the bi-weekly and aripiprazole once-monthly groups. In addition, patients treated with PP1M and PP3M used a significantly lower dose of haloperidol equivalents versus the bi-weekly LAIs group. Finally, significantly higher doses of biperiden were used by the bi-weekly LAIs group. CONCLUSION: In conclusion, paliperidone LAIs reduced hospital re-admissions and, as aripiprazole once monthly, lowered concomitant psychiatric medication versus the bi-weekly LAIs. Further research and analysis of subgroups are needed; however, these findings might be useful for clinicians.

Switching from clozapine to paliperidone palmitate-3-monthly improved obesity, hyperglycemia and dyslipidemia lowering antipsychotic dose equivalents in a treatment-resistant schizophrenia cohort.

Clozapine, an antipsychotic developed in 1958, is considered the gold standard and the treatment of choice in treatment-resistant schizophrenia despite its side effects and despite 40-70% of these patients not responding to clozapine. In the last decade, new antipsychotics, such as paliperidone palmitate (PP), have emerged as well as its long acting-injectable (LAI) formulations, available as PP-1-monthly (PP1M) and the newest PP-3-montlhy (PP3M). Despite paliperidone having shown a similar efficacy as others antipsychotics for the treatment of schizophrenia, and that PP3M has been shown to reduce relapses compared to oral formulations, no study has been carried out in treatment-resistant schizophrenia. The aim of our study was to carry out an exploratory evaluation of endocrine and hepatic profiles as well as the concomitant treatments associated to PP3M vs. clozapine, the gold standard, in patients with treatment-resistant schizophrenia. We designed a retrospective study. A total number of 33 patients previously diagnosed as schizophrenics treatment-resistant, who were prescribed clozapine followed by PP1M and PP3M when available, were selected. Demographic data, BMI, hepatic enzymes (glutamic oxaloacetic transaminase, glutamate-pyruvate transaminase and gamma-glutamyl transferase (GGT)], thyroid function (thyroid stimulating hormone), blood platelets and both white and red blood cells as well as the use of concomitant antipsychotics, benzodiazepines and biperiden were compared under treatment with clozapine and PP3M. Antipsychotics and benzodiazepines dosages were compared using by the defined daily dose (DDD) method and haloperidol or diazepam dose equivalents. All statistical analyses were performed using the paired Student t-test for repeated measures. Our data showed that patients under treatment with PP3M showed a significant decrease in BMI (P < 0.01), glucose (P < 0.01), cholesterol (P < 0.05) and triglycerides (P < 0.01) when compared with basal values under treatment with clozapine. Hepatic cholestasis enzyme, GGT, were significantly elevated (P < 0.05) under treatment with clozapine when compared to PP3M. Switching clozapine to PP3M led to a significant lower pharmacological exposure to antipsychotics, by both the DDD (P < 0.05) and haloperidol dose equivalents (P < 0.001) methods without increasing the dose of benzodiazepines while biperiden was more used under PP3M. Finally, antipsychotic monotherapy was higher and less polypharmacy was used with PP3M. In conclusion, our findings suggest that switching clozapine to PP3M improved endocrine and hepatic profile with a lower total exposure to antipsychotics. More studies are needed to truly establish the role of PP3M in treatment-resistant schizophrenia and should be compared against clozapine by using clinical trials.

Methamphetamine withdrawal induces activation of CRF neurons in the brain stress system in parallel with an increased activity of cardiac sympathetic pathways.

Methamphetamine (METH) addiction is a major public health problem in some countries. There is evidence to suggest that METH use is associated with increased risk of developing cardiovascular problems. Here, we investigated the effects of chronic METH administration and withdrawal on the activation of the brain stress system and cardiac sympathetic pathways. Mice were treated with METH (2 mg/kg, i.p.) for 10 days and left to spontaneous withdraw for 7 days. The number of corticotrophin-releasing factor (CRF), c-Fos, and CRF/c-Fos neurons was measured by immunohistochemistry in the paraventricular nucleus of the hypothalamus (PVN) and the oval region of the bed nucleus of stria terminalis (ovBNST), two regions associated with cardiac sympathetic control. In parallel, levels of catechol-o-methyl-transferase (COMT), tyrosine hydroxylase (TH), and heat shock protein 27 (Hsp27) were measured in the heart. In the brain, chronic-METH treatment enhanced the number of c-Fos neurons and the CRF neurons with c-Fos signal (CRF+/c-Fos+) in PVN and ovBNST. METH withdrawal increased the number of CRF+ neurons. In the heart, METH administration induced an increase in soluble (S)-COMT and membrane-bound (MB)-COMT without changes in phospho (p)-TH, Hsp27, or pHsp27. Similarly, METH withdrawal increased the expression of S- and MB-COMT. In contrast to chronic treatment, METH withdrawal enhanced levels of (p)TH and (p)Hsp27 in the heart. Overall, our results demonstrate that chronic METH administration and withdrawal activate the brain CRF systems associated with the heart sympathetic control and point towards a METH withdrawal induced activation of sympathetic pathways in the heart. Our findings provide further insight in the mechanism underlining the cardiovascular risk associated with METH use and proposes targets for its treatment.

Role of CRF1 receptor in post-incisional plasma extravasation and nociceptive responses in mice.

The corticotropin-releasing factor (CRF) is involved in a number of physiological functions including pain perception. The purpose of this study was to evaluate the role of CRF1 receptor in the long-lasting post-surgical changes in somatic nociceptive thresholds and in local inflammatory responses, using genetically engineered mice lacking functional CRF1 receptor. Animals underwent a plantar incision under anaesthesia with remifentanil (80µg/kg s.c.) and sevoflurane. Mechanical thresholds (von Frey) and plasma extravasation (Evan's blue) were evaluated at different time points. On postoperative day 20, mechanical thresholds had returned to baseline in CD1 mice (3.07±6.21%), while B6,129CRHtklee mice presented significant hyperalgesia, which was similar in wild-type (WT) (-29.81±8.89%) and CRF1 receptor knockout (KO) (-37.10±10.75%) mice, showing strain differences. The administration of naloxone (1mg/kg, s.c.) on postoperative day 21 produced hyperalgesia revealing surgery-induced latent pain sensitization. The extent of hyperalgesia was greater in KO versus WT mice, suggesting a role of CRF1 receptors in the upward modulation of endogenous opioid release. Furthermore, two days after surgery, plasma extravasation returned to baseline in WT mice but remained elevated in KO mice. In non-manipulated B6,129CRHtklee KO mice we observed an increase in the number of writhes (41.25±11.36) versus WT (23.80±4.71), while in the tail immersion test no differences could be detected. Our results show that CRF/CRF1 receptors seem to be a protective role in latent pain sensitization induced by surgery and in the local inflammatory response to injury.

Methamphetamine abstinence induces changes in µ-opioid receptor, oxytocin and CRF systems: Association with an anxiogenic phenotype.

The major challenge in treating methamphetamine addicts is the maintenance of a drug free-state since they experience negative emotional symptoms during abstinence, which may trigger relapse. The neuronal mechanisms underlying long-term withdrawal and relapse are currently not well-understood. There is evidence suggesting a role of the oxytocin (OTR), µ-opioid receptor (MOPr), dopamine D2 receptor (D2R), corticotropin-releasing factor (CRF) systems and the hypothalamic-pituitary-adrenal (HPA)-axis in the different stages of methamphetamine addiction. In this study, we aimed to characterize the behavioral effects of methamphetamine withdrawal in mice and to assess the modulation of the OTR, MOPr, D2R, CRF and HPA-axis following chronic methamphetamine administration and withdrawal. Ten-day methamphetamine administration (2 mg/kg) increased OTR binding in the amygdala, whilst 7 days of withdrawal induced an upregulation of this receptor in the lateral septum. Chronic methamphetamine treatment increased plasma OT levels that returned to control levels following withdrawal. In addition, methamphetamine administration and withdrawal increased striatal MOPr binding, as well as c-Fos(+)/CRF(+) neuronal expression in the amygdala, whereas an increase in plasma corticosterone levels was observed following METH administration, but not withdrawal. No differences were observed in the D2R binding following METH administration and withdrawal. The alterations in the OTR, MOPr and CRF systems occurred concomitantly with the emergence of anxiety-related symptoms and the development of psychomotor sensitization during withdrawal. Collectively, our findings indicate that chronic methamphetamine use and abstinence can induce brain-region specific neuroadaptations of the OTR, MOPr and CRF systems, which may, at least, partly explain the withdrawal-related anxiogenic effects.

The oxytocin analogue carbetocin prevents priming-induced reinstatement of morphine-seeking: Involvement of dopaminergic, noradrenergic and MOPr systems.

Relapse to illicit drug-seeking following abstinence is a major challenge for the treatment of addiction as no effective pharmacotherapy is available. We have recently shown that activating the central oxytocinergic system prevents emotional impairment and stress-induced reinstatement associated with opioid withdrawal. Here, we investigated whether the oxytocin analogue carbetocin (CBT) is able to reverse morphine-primed reinstatement of conditioned-place preference (CPP) in mice. The mechanism underlining the behavioural effect of CBT was investigated by assessing the involvement of the striatal noradrenergic and dopaminergic systems in CBT reversal of priming- and stress-induced reinstatement of opioid CPP. In addition, given recent evidence suggesting the presence of oxytocin receptor (OTR)-µ-opioid receptor (MOPr) interactions in the brain, we further explored these interactions by carrying out OTR autoradiographic binding in brain of mice lacking MOPr. CBT administration prevented priming-induced reinstatement of morphine CPP. While an acute effect of CBT in enhancing dopamine turnover was observed following stress- and priming-induced reinstatement, CBT significantly decreased striatal noradrenaline turnover only following priming-induced reinstatement. Moreover, a significant brain region- specific increase in OTR binding was observed in MOPr knockout mice, indicating the presence of a possible OTR-MOPr interaction, which may be involved in the modulation of relapse. These results support the oxytocinergic system as a promising target for the prevention of relapse to opioid use and highlight the differential involvement of monoaminergic systems on the effects of OTR stimulation in preventing stress- and priming-induced reinstatement of opioid CPP behaviour.

CP-154,526 Modifies CREB Phosphorylation and Thioredoxin-1 Expression in the Dentate Gyrus following Morphine-Induced Conditioned Place Preference.

Corticotropin-releasing factor (CRF) acts as neuro-regulator of the behavioral and emotional integration of environmental and endogenous stimuli associated with drug dependence. Thioredoxin-1 (Trx-1) is a functional protein controlling the redox status of several proteins, which is involved in addictive processes. In the present study, we have evaluated the role of CRF1 receptor (CRF1R) in the rewarding properties of morphine by using the conditioned place preference (CPP) paradigm. We also investigate the effects of the CRF1R antagonist, CP-154,526, on the morphine CPP-induced activation of CRF neurons, CREB phosphorylation and Trx expression in paraventricular nucleus (PVN) and dentate gyrus (DG) of the mice brain. CP-154,526 abolished the acquisition of morphine CPP and the increase of CRF/pCREB positive neurons in PVN. Moreover, this CRF1R antagonist prevented morphine-induced CRF-immunoreactive fibers in DG, as well as the increase in pCREB expression in both the PVN and DG. In addition, morphine exposure induced an increase in Trx-1 expression in DG without any alterations in PVN. We also observed that the majority of pCREB positive neurons in DG co-expressed Trx-1, suggesting that Trx-1 could activate CREB in the DG, a brain region involved in memory consolidation. Altogether, these results support the idea that CRF1R antagonist blocked Trx-1 expression and pCREB/Trx-1 co-localization, indicating a critical role of CRF, through CRF1R, in molecular changes involved in morphine associated behaviors.

Sex differences between CRF1 receptor deficient mice following naloxone-precipitated morphine withdrawal in a conditioned place aversion paradigm: implication of HPA axis.

BACKGROUND: Extinction period of positive affective memory of drug taking and negative affective memory of drug withdrawal, as well as the different response of men and women might be important for the clinical treatment of drug addiction. We investigate the role of corticotropin releasing factor receptor type one (CRF1R) and the different response of male and female mice in the expression and extinction of the aversive memory. METHODOLOGY/PRINCIPAL FINDING: We used genetically engineered male and female mice lacking functional CRF1R. The animals were rendered dependent on morphine by intraperitoneally injection of increasing doses of morphine (10-60 mg/kg). Negative state associated with naloxone (1 mg/kg s.c.)-precipitated morphine withdrawal was examined by using conditioned place aversion (CPA) paradigm. No sex differences for CPA expression were found in wild-type (n = 29) or CRF1R knockout (KO) mice (n = 29). However, CRF1R KO mice presented less aversion score than wild-type mice, suggesting that CRF1R KO mice were less responsive than wild-type to continuous associations between drug administration and environmental stimuli. In addition, CPA extinction was delayed in wild-type and CRF1R KO male mice compared with females of both genotypes. The genetic disruption of the CRF1R pathway decreased the period of extinction in males and females suggesting that CRF/CRF1R is implicated in the duration of aversive memory. Our results also showed that the increase in adrenocorticotropic hormone (ACTH) levels observed in wild-type (n = 11) mice after CPA expression, were attenuated in CRF1R KO mice (n = 10). In addition, ACTH returned to the baseline levels in males and females once CPA extinction was finished. CONCLUSION/SIGNIFICANCE: These results suggest that, at least, CPA expression is partially due to an increase in plasma ACTH levels, through activation of CRF1R, which can return when CPA extinction is finished.

Sympathetic activity induced by naloxone-precipitated morphine withdrawal is blocked in genetically engineered mice lacking functional CRF1 receptor.

There is large body evidence indicating that stress can lead to cardiovascular disease. However, the exact brain areas and the mechanisms involved remain to be revealed. Here, we performed a series of experiments to characterize the role of CRF1 receptor (CRF1R) in the stress response induced by naloxone-precipitated morphine withdrawal. The experiments were performed in the hypothalamic paraventricular nucleus (PVN) ventrolateral medulla (VLM), brain regions involved in the regulation of cardiovascular activity, and in the right ventricle by using genetically engineered mice lacking functional CRF1R levels (KO). Mice were treated with increasing doses of morphine and withdrawal was precipitated by naloxone administration. Noradrenaline (NA) turnover, c-Fos, expression, PKA and TH phosphorylated at serine 40, was evaluated by high-performance liquid chromatography (HPLC), immunohistochemistry and immunoblotting. Morphine withdrawal induced an enhancement of NA turnover in PVN in parallel with an increase in TH neurons expressing c-Fos in VLM in wild-type mice. In addition we have demonstrated an increase in NA turnover, TH phosphorylated at serine 40 and PKA levels in heart. The main finding of the present study was that NA turnover, TH positive neurons that express c-Fos, TH phosphorylated at serine 40 and PKA expression observed during morphine withdrawal were significantly inhibited in CRF1R KO mice. Our results demonstrate that CRF/CRF1R activation may contribute to the adaptive changes induced by naloxone-precipitated withdrawal in the heart and in the brain areas which modulate the cardiac sympathetic function and suggest that CRF/CRF1R pathways could be contributing to cardiovascular disease associated to opioid addiction.

Corticotropin-releasing factor (CRF) receptor-1 is involved in cardiac noradrenergic activity observed during naloxone-precipitated morphine withdrawal.

BACKGROUND AND PURPOSE: The negative affective states of withdrawal involve the recruitment of brain and peripheral stress circuitry [noradrenergic activity, induction of the hypothalamic-pituitary-adrenocortical (HPA) axis and activation of heat shock proteins (Hsps)]. Corticotropin-releasing factor (CRF) pathways are important mediators in the negative symptoms of opioid withdrawal. We performed a series of experiments to characterize the role of the CRF1 receptor in the response of stress systems to morphine withdrawal and its effect in the heart using genetically engineered mice lacking functional CRF1 receptors. EXPERIMENTAL APPROACH: Wild-type and CRF1 receptor-knockout mice were treated with increasing doses of morphine. Precipitated withdrawal was induced by naloxone. Plasma adrenocorticotropic hormone (ACTH) and corticosterone levels, the expression of myocardial Hsp27, Hsp27 phosphorylated at Ser8², membrane (MB)- COMT, soluble (S)-COMT protein and NA turnover were evaluated by RIA, immunoblotting and HPLC. KEY RESULTS: During morphine withdrawal we observed an enhancement of NA turnover in parallel with an increase in mean arterial blood pressure (MAP) and heart rate (HR) in wild-type mice. In addition, naloxone-precipitated morphine withdrawal induced an activation of HPA axis and Hsp27. The principal finding of the present study was that plasma ACTH and corticosterone levels, MB-COMT, S-COMT, NA turnover, and Hsp27 expression and activation observed during morphine withdrawal were significantly inhibited in the CRF1 receptor-knockout mice. CONCLUSION AND IMPLICATIONS: Our results demonstrate that CRF/CRF1 receptor activation may contribute to stress-induced cardiovascular dysfunction after naloxone-precipitated morphine withdrawal and suggest that CRF/CRF1 receptor pathways could contribute to cardiovascular disease associated with opioid addiction.