Long-Term, Targeted Delivery of GDNF from Encapsulated Cells Is Neuroprotective and Reduces Seizures in the Pilocarpine Model of Epilepsy.

Neurotrophic factors are candidates for treating epilepsy, but their development has been hampered by difficulties in achieving stable and targeted delivery of efficacious concentrations within the desired brain region. We have developed an encapsulated cell technology that overcomes these obstacles by providing a targeted, continuous, de novo synthesized source of high levels of neurotrophic molecules from human clonal ARPE-19 cells encapsulated into hollow fiber membranes. Here we illustrate the potential of this approach for delivering glial cell line-derived neurotrophic factor (GDNF) directly to the hippocampus of epileptic rats. In vivo studies demonstrated that bilateral intrahippocampal implants continued to secrete GDNF that produced high hippocampal GDNF tissue levels in a long-term manner. Identical implants robustly reduced seizure frequency in the pilocarpine model. Seizures were reduced rapidly, and this effect increased in magnitude over 3 months, ultimately leading to a reduction of seizures by 93%. This effect persisted even after device removal, suggesting potential disease-modifying benefits. Importantly, seizure reduction was associated with normalized changes in anxiety and improved cognitive performance. Immunohistochemical analyses revealed that the neurological benefits of GDNF were associated with the normalization of anatomical alterations accompanying chronic epilepsy, including hippocampal atrophy, cell degeneration, loss of parvalbumin-positive interneurons, and abnormal neurogenesis. These effects were associated with the activation of GDNF receptors. All in all, these results support the concept that the implantation of encapsulated GDNF-secreting cells can deliver GDNF in a sustained, targeted, and efficacious manner, paving the way for continuing preclinical evaluation and eventual clinical translation of this approach for epilepsy.SIGNIFICANCE STATEMENT Epilepsy is one of the most common neurological conditions, affecting millions of individuals of all ages. These patients experience debilitating seizures that frequently increase over time and can associate with significant cognitive decline and psychiatric disorders that are generally poorly controlled by pharmacotherapy. We have developed a clinically validated, implantable cell encapsulation system that delivers high and consistent levels of GDNF directly to the brain. In epileptic animals, this system produced a progressive and permanent reduction (>90%) in seizure frequency. These benefits were accompanied by improvements in cognitive and anxiolytic behavior and the normalization of changes in CNS anatomy that underlie chronic epilepsy. Together, these data suggest a novel means of tackling the frequently intractable neurological consequences of this devastating disorder.

Cytokine-, Neurotrophin-, and Motor Rehabilitation-Induced Plasticity in Parkinson's Disease.

Neuroinflammation and cytokine-dependent neurotoxicity appear to be major contributors to the neuropathology in Parkinson's disease (PD). While pharmacological advancements have been a mainstay in the treatment of PD for decades, it is becoming increasingly clear that nonpharmacological approaches including traditional and nontraditional forms of exercise and physical rehabilitation can be critical adjunctive or even primary treatment avenues. Here, we provide an overview of preclinical and clinical research detailing the biological role of proinflammatory molecules in PD and how motor rehabilitation can be used to therapeutically modulate neuroinflammation, restore neural plasticity, and improve motor function in PD.

Glucocorticoid receptors modulate dendritic spine plasticity and microglia activity in an animal model of Alzheimer's disease.

Chronic exposure to high circulating levels of glucocorticoids (GCs) may be a key risk factor for Alzheimer's Disease (AD) development and progression. In addition, hyper-activation of glucocorticoid receptors (GRs) induces brain alterations comparable to those produced by AD. In transgenic mouse models of AD, GCs increase the production of the most important and typical hallmarks of this dementia such as: Aß40, Aß42 and tau protein (both the total tau and its hyperphosphorylated isoforms). Moreover, GCs in brain are pivotal regulators of dendritic spine turnover and microglia activity, two phenomena strongly altered in AD. Although it is well-established that GCs primes the neuroinflammatory response in the brain to some stimuli, it is unknown whether or how GRs modulates dendritic spine plasticity and microglia activity in AD. In this study, we evaluated, using combined Golgi Cox and immunofluorescence techniques, the role of GR agonists and antagonists on dendritic spine plasticity and microglia activation in hippocampus of 3xTg-AD mice. We found that dexamethasone, an agonist of GRs, was able to significantly reduce dendritic spine density and induced proliferation and activation of microglia in CA1 region of hippocampus of 3xTg-AD mice at 6 and 10 months of age. On the contrary, the treatment with mifepristone, an antagonist of GRs, strongly enhanced dendritic spine density, decreased microglia density and improved the behavioural performance of 3xTg-AD mice. Additionally, primary microglial cells in vitro were directly activated by dexamethasone. Together, these data demonstrate that stress exacerbates AD and promotes a rapid progression of the pathology acting on both neurons and glial cells, supporting an important pro-inflammatory role of GC within CNS in AD. Consequently, these results further strengthen the need to test clinical interventions that correct GCs dysregulation as promising therapeutic strategy to delay the onset and slow down the progression of AD.

Widespread Striatal Delivery of GDNF from Encapsulated Cells Prevents the Anatomical and Functional Consequences of Excitotoxicity.

Methods: Human ARPE-19 cells engineered to secrete high levels of the glial cell line-derived neurotrophic factor (GDNF) were encapsulated into hollow fiber membranes. The devices were implanted into the rat striatum 1 week prior to striatal quinolinic acid injections. Animals were evaluated using a battery of validated motor tests, and histology was performed to determine the extent of GDNF diffusion and associated prevention of neuronal cell loss and behavioral deficits. Results: Encapsulated cell-based delivery of GDNF produced widespread distribution of GDNF throughout the entire implanted striatum. Stereological estimates of striatal neuron number and volume of lesion size revealed that GDNF delivery resulted in near complete neuroprotection. Conclusions: Delivery of neurotrophic molecules such as GDNF using encapsulated cells has reached a technological point where clinical evaluation is justified. Because GDNF has been effective in animal models of Parkinson's disease, stroke, epilepsy, and Huntington's disease, among other debilitating neurodegenerative diseases, encapsulated cell-based delivery of GDNF might represent one innovative means of slowing the neural degeneration seen in a myriad of currently untreatable neurological diseases.

Eltoprazine prevents levodopa-induced dyskinesias by reducing striatal glutamate and direct pathway activity.

BACKGROUND: Preclinical and clinical evidence that the serotonergic system plays a major role in levodopa-induced dyskinesias has been provided. Selective serotonin (5-hydroxytryptamine; 5-HT) 5-HT1A or 5-HT1B receptor agonists, and, very recently, the mixed 5-HT1A /5-HT1B receptor agonist, eltoprazine, proved effective in inhibiting L-dopa-induced dyskinesias in experimental animals and parkinsonian patients. Here, we investigate the mechanisms underlying this effect. METHODS: Microdialysis was employed in 6-hydroxydopamine-hemilesioned rats chronically treated with L-dopa alone or in combination with eltoprazine. Gamma-aminobutyric acid (GABA) and glutamate levels were monitored on L-dopa in the dopamine-depleted striatum and ipsilateral SNr. Motor activity on the rotarod was assessed, both off and on L-dopa. Western blot was used to quantify ex vivo striatal levels of phosphorylated extracellular signal-regulated kinase 1 and 2. Striatal and nigral amino acid levels, as well as striatal dopamine levels, were also monitored in L-dopa-primed dyskinetic rats acutely challenged with L-dopa and eltoprazine. RESULTS: Eltoprazine attenuated the development and expression of dyskinesias, preserving motor coordination on the rotarod. Eltoprazine prevented the rise of nigral amino acids and striatal glutamate levels, as well as the increase in striatal phosphorylated extracellular signal-regulated kinase 1 and 2, associated with dyskinesias. However, eltoprazine did not affect the L-dopa-induced increase in striatal dopamine. CONCLUSIONS: Eltoprazine inhibits the sensitization of striatonigral medium-sized GABA spiny neurons (the direct pathway) to L-dopa and their overactivation associated with dyskinesias appearance. Activation of 5-HT1A and 5-HT1B receptors regulating striatal glutamate transmission, but not striatal ectopic dopamine release, might underlie the symptomatic effect of eltoprazine.

Modeling fall propensity in Parkinson's disease: deficits in the attentional control of complex movements in rats with cortical-cholinergic and striatal-dopaminergic deafferentation.

Cognitive symptoms, complex movement deficits, and increased propensity for falls are interrelated and levodopa-unresponsive symptoms in patients with Parkinson's disease (PD). We developed a test system for the assessment of fall propensity in rats and tested the hypothesis that interactions between loss of cortical cholinergic and striatal dopaminergic afferents increase fall propensity. Rats were trained to traverse stationary and rotating rods, placed horizontally or at inclines, and while exposed to distractors. Rats also performed an operant Sustained Attention Task (SAT). Partial cortical cholinergic and/or caudate dopaminergic deafferentation were produced by bilateral infusions of 192 IgG-saporin (SAP) into the basal forebrain and/or 6-hydroxydopamine (6-OHDA) into the caudate nucleus, respectively, modeling the lesions seen in early PD. Rats with dual cholinergic-dopaminergic lesions (DL) fell more frequently than SAP or 6-OHDA rats. Falls in DL rats were associated with incomplete rebalancing after slips and low traversal speed. Ladder rung walking and pasta handling performance did not indicate sensorimotor deficits. SAT performance was impaired in DL and SAP rats; however, SAT performance and falls were correlated only in DL rats. Furthermore, in DL rats, but not in rats with only dopaminergic lesions, the placement and size of dopaminergic lesion correlated significantly with fall rates. The results support the hypothesis that after dual cholinergic-dopaminergic lesions, attentional resources can no longer be recruited to compensate for diminished striatal control of complex movement, thereby "unmasking" impaired striatal control of complex movements and yielding falls.

Cholinergic control over attention in rats prone to attribute incentive salience to reward cues.

Some rats [sign-trackers (STs)] are especially prone to attribute incentive salience to reward cues, relative to others [goal-trackers (GTs)]. Thus, reward cues are more likely to promote maladaptive reward-seeking behavior in STs than GTs. Here, we asked whether STs and GTs differ on another trait that can contribute to poor restraint over behavior evoked by reward cues. We report that, relative to GTs, STs have poor control over attentional performance, due in part to insufficient cholinergic stimulation of cortical circuitry. We found that, relative to GTs, STs showed poor performance on a sustained attention task (SAT). Furthermore, their performance fluctuated rapidly between periods of good to near-chance performance. This finding was reproduced using a separate cohort of rats. As demonstrated earlier, performance on the SAT was associated with increases in extracellular levels of cortical acetylcholine (ACh); however, SAT performance-associated increases in ACh levels were significantly attenuated in STs relative to GTs. Consistent with the view that the modulatory effects of ACh involve stimulation of α4ß2* nicotinic ACh receptors (nAChRs), systemic administration of the partial nAChR agonist ABT-089 improved SAT performance in STs and abolished the difference between SAT-associated ACh levels in STs and GTs. Neither the nonselective nAChR agonist nicotine nor the psychostimulant amphetamine improved SAT performance. These findings suggest that individuals who have a propensity to attribute high-incentive salience to reward cues also exhibit relatively poor attentional control. A combination of these traits may render individuals especially vulnerable to disorders, such as obesity and addiction.

Ecocebo: How the interaction between environment and drug effects may improve pharmacotherapy outcomes.

This narrative review describes the research on the effects of the association between environmental context and medications, suggesting the benefit of specific design interventions in adjunction to pharmacotherapy. The literature on Evidence-Based Design (EBD) studies and Neuro-Architecture show how contact with light, nature, and specific physical features of urban and interior architecture may enhance the effects of analgesic, anxiolytics, and antidepressant drugs. This interaction mirrors those already known between psychedelics, drugs of abuse, and setting. Considering that the physical feature of space is a component of the complex placebo configuration, the aim is to highlight those elements of built or natural space that may help to improve drug response in terms of efficacy, tolerability, safety, and compliance. Ecocebo, the integration of design approaches such as EBD and Neuro-Architecture may thus contribute to a more efficient, cost-sensitive, and sustainable pharmacotherapy.

Time to pay attention: attentional performance time-stamped prefrontal cholinergic activation, diurnality, and performance.

Although the impairments in cognitive performance that result from shifting or disrupting daily rhythms have been demonstrated, the neuronal mechanisms that optimize fixed-time daily performance are poorly understood. We previously demonstrated that daily practice of a sustained attention task (SAT) evokes a diurnal activity pattern in rats. Here, we report that SAT practice at a fixed time produced practice time-stamped increases in prefrontal cholinergic neurotransmission that persisted after SAT practice was terminated and in a different environment. SAT time-stamped cholinergic activation occurred regardless of whether the SAT was practiced during the light or dark phase or in constant-light conditions. In contrast, prior daily practice of an operant schedule of reinforcement, albeit generating more rewards and lever presses per session than the SAT, neither activated the cholinergic system nor affected the animals' nocturnal activity pattern. Likewise, food-restricted animals exhibited strong food anticipatory activity (FAA) and attenuated activity during the dark phase but FAA was not associated with increases in prefrontal cholinergic activity. Removal of cholinergic neurons impaired SAT performance and facilitated the reemergence of nocturnality. Shifting SAT practice away from a fixed time resulted in significantly lower performance. In conclusion, these experiments demonstrated that fixed-time, daily practice of a task assessing attention generates a precisely practice time-stamped activation of the cortical cholinergic input system. Time-stamped cholinergic activation benefits fixed-time performance and, if practiced during the light phase, contributes to a diurnal activity pattern.

Where Dopaminergic and Cholinergic Systems Interact: A Gateway for Tuning Neurodegenerative Disorders.

Historically, many investigations into neurodegenerative diseases have focused on alterations in specific neuronal populations such as, for example, the loss of midbrain dopaminergic neurons in Parkinson's disease (PD) and loss of cholinergic transmission in Alzheimer's disease (AD). However, it has become increasingly clear that mammalian brain activities, from executive and motor functioning to memory and emotional responses, are strictly regulated by the integrity of multiple interdependent neuronal circuits. Among subcortical structures, the dopaminergic nigrostriatal and mesolimbic pathways as well as cholinergic innervation from basal forebrain and brainstem, play pivotal roles in orchestrating cognitive and non-cognitive symptoms in PD and AD. Understanding the functional interactions of these circuits and the consequent neurological changes that occur during degeneration provides new opportunities to understand the fundamental inter-workings of the human brain as well as develop new potential treatments for patients with dysfunctional neuronal circuits. Here, excerpted from a session of the European Behavioral Pharmacology Society meeting (Braga, Portugal, August 2019), we provide an update on our recent work in behavioral and cellular neuroscience that primarily focuses on interactions between cholinergic and dopaminergic systems in PD models, as well as stress in AD. These brief discussions include descriptions of (1) striatal cholinergic interneurons (CINs) and PD, (2) dopaminergic and cholinergic modulation of impulse control, and (3) the use of an implantable cell-based system for drug delivery directly the into brain and (4) the mechanisms through which day life stress, a risk factor for AD, damage protein and RNA homeostasis leading to AD neuronal malfunction.

Implication of sestrin3 in epilepsy and its comorbidities.

Epilepsy is a serious neurological disorder affecting about 1% of the population worldwide. Epilepsy may arise as a result of acquired brain injury, or as a consequence of genetic predisposition. To date, genome-wide association studies and exome sequencing approaches have provided limited insights into the mechanisms of acquired brain injury. We have previously reported a pro-epileptic gene network, which is conserved across species, encoding inflammatory processes and positively regulated by sestrin3 (SESN3). In this study, we investigated the phenotype of SESN3 knock-out rats in terms of susceptibility to seizures and observed a significant delay in status epilepticus onset in SESN3 knock-out compared to control rats. This finding confirms previous in vitro and in vivo evidence indicating that SESN3 may favour occurrence and/or severity of seizures. We also analysed the phenotype of SESN3 knock-out rats for common comorbidities of epilepsy, i.e., anxiety, depression and cognitive impairment. SESN3 knock-out rats proved less anxious compared to control rats in a selection of behavioural tests. Taken together, the present results suggest that SESN3 may regulate mechanisms involved in the pathogenesis of epilepsy and its comorbidities.

From the Gut to the Brain and Back: Therapeutic Approaches for the Treatment of Network Dysfunction in Parkinson's Disease.

Parkinson's disease (PD) is a complex, multisystem, progressive, degenerative disorder characterized by severe, debilitating motor dysfunction, cognitive impairments, and mood disorders. Although preclinical research has traditionally focused on the motor deficits resulting from the loss of nigrostriatal dopaminergic neurons, up to two thirds of PD patients present separate and distinct behavioral changes. Loss of basal forebrain cholinergic neurons occurs as early as the loss of dopaminergic cells and contributes to the cognitive decline in PD. In addition, attentional deficits can limit posture control and movement efficacy caused by dopaminergic cell loss. Complicating the picture further is intracellular α-synuclein accumulation beginning in the enteric nervous system and diffusing to the substantia nigra through the dorsal motor neurons of the vagus nerve. It seems that α-synuclein's role is that of mediating dopamine synthesis, storage, and release, and its function has not been completely understood. Treating a complex, multistage network disorder, such as PD, likely requires a multipronged approach. Here, we describe a few approaches that could be used alone or perhaps in combination to achieve a greater mosaic of behavioral benefit. These include (1) using encapsulated, genetically modified cells as delivery vehicles for administering neuroprotective trophic factors, such as GDNF, in a direct and sustained means to the brain; (2) immunotherapeutic interventions, such as vaccination or the use of monoclonal antibodies against aggregated, pathological α-synuclein; (3) the continuous infusion of levodopa-carbidopa through an intestinal gel pad to attenuate the loss of dopaminergic function and manage the motor and non-motor complications in PD patients; and (4) specific rehabilitation treatment programs for drug-refractory motor complications.

The metaplastic effects of ketamine on sucrose renewal and contextual memory reconsolidation in rats.

Metaplastic effects of the NMDARs blocker ketamine at the neural and behavioural levels have been described as potential mechanisms underlying the beneficial effects in treatment-resistant depression. However, ketamine effects on addictive behaviours are still unexplored. In the present study, we investigated the effects of ketamine given under a "metaplasticity-inducing dose regimen" on sucrose-related renewal and contextual memory reconsolidation in rats. After a molecular analysis of ketamine modulation of GluN2B, GluA1 and mGluR5 receptors levels in nucleus accumbens, hippocampus and amygdala, two behavioural models were used to investigate ketamine effects: i) context-induced renewal of sucrose-seeking, and ii) sucrose memory reconsolidation. Ketamine was administrated 24 h before the renewal test or the retrieval. At the molecular level, ketamine i) decreased GluN2B, GluA1 and mGluR5 receptors in hippocampus, ii) decreased GluA1 and mGluR5 but increased GluN2B in nucleus accumbens and iii) increased GluN2B and mGluR5 in amygdala. At the behavioural level, ketamine given prior to renewal significantly inhibited responding compared to vehicle, while no significant effects were observed on reconsolidation of contextual memory. In conclusion, the molecular analysis of ketamine metaplastic effects in key brain areas suggest a possible involvement of glutamatergic receptors in the inhibition of sucrose renewal but not of contextual memory reconsolidation. The inhibition of renewal could be correlated to hippocampal and accumbal decreased levels of GluA1 and mGluR5, whereas, the lack of effect on contextual memory reconsolidation could be correlated to decreased GluN2B expression in hippocampus, landmark of destabilization-insensitive state.

Long-term, stable, targeted biodelivery and efficacy of GDNF from encapsulated cells in the rat and Goettingen miniature pig brain.

Delivering glial cell line-derived neurotrophic factor (GDNF) to the brain is a potential treatment for Parkinson's Disease (PD). Here we use an implantable encapsulated cell technology that uses modified human clonal ARPE-19 â€‹cells to deliver of GDNF to the brain. In vivo studies demonstrated sustained delivery of GDNF to the rat striatum over 6 months. Anatomical benefits and behavioral efficacy were shown in 6-OHDA lesioned rats where nigral dopaminergic neurons were preserved in neuroprotection studies and dopaminergic fibers were restored in neurorecovery studies. When larger, clinical-sized devices were implanted for 3 months into the putamen of Göttingen minipigs, GDNF was widely distributed throughout the putamen and caudate producing a significant upregulation of tyrosine hydroxylase immunohistochemistry. These results are the first to provide clear evidence that implantation of encapsulated GDNF-secreting cells deliver efficacious and biologically relevant amounts of GDNF in a sustained and targeted manner that is scalable to treat the large putamen in patients with Parkinson's disease.

Cell-laden alginate hydrogels for the treatment of diabetes.

INTRODUCTION: Diabetes mellitus is an ever-increasing medical condition that currently suffers 1 of 11 adults who may have lifelong commitment with insulin injections. Cell-laden hydrogels releasing insulin may provide the ultimate means of correcting diabetes. Here, we provide insights of this cell-based approach including latest preclinical and clinical progress both from academia and industry. AREA COVERED: The present article focuses on reviewing latest advances in cell-laden hydrogels both from the technological and biological perspective. The most relevant clinical results including clinical trials are also discussed. EXPERT OPINION: Current progress in technological issues (stem cells, devices, biomaterials) have contributed cell encapsulation science to have a very relevant progress in the field of diabetes treatment.

Reconsolidation of sucrose instrumental memory in rats: The role of retrieval context.

Memory reconsolidation enables the update of a previously consolidated memory trace after its reactivation. Although Pavlovian memory reconsolidation has been widely demonstrated, instrumental memory reconsolidation is still debated. The most critical issue on instrumental memory reconsolidation findings have mainly been linked to the presence of specific boundary conditions for reactivation, for instance contextual parameters. In this study, we investigated the role of the spatial context on molecular markers of sucrose instrumental memory reactivation. Following withdrawal, rats previously conditioned to sucrose self-administration underwent either instrumental memory retrieval or no-retrieval in the conditioned context (Context A, AA condition) or in a modified version of the conditioned context (Context B, AB condition). Two hours later, the level of GluA1 and GluN2B receptors, Zif268 and phosphorylated-rpS6 (rpS6P) was measured in key brain areas for memory reactivation. Retrieval in Context A significantly increased GluA1Rs and GluN2BRs in amygdala compared to no-retrieval, indicating that memory successfully reactivated and destabilized. Moreover, Zif268 level was significantly increased after retrieval in Context A in the nucleus accumbens shell, central and basolateral amygdala but not in the hippocampus, while retrieval in Context B significantly increased Zif268 level in all brain areas. On the other hand, rpS6P level was increased in the nucleus accumbens shell and central amygdala, but decreased in the hippocampus, after retrieval in Context A, while retrieval in Context B did not change rpS6P level in brain areas, except for a small but significant decrease in hippocampus. While the increase of Zif268 level indicated that memory reactivation has been triggered in both the conditions, the lack of change in rpS6P levels after retrieval in Context B - in particular in the central amygdala - suggests that the reconsolidation process could not occur after memory reactivation in a context different from the conditioned one.

Opposite environmental regulation of heroin and amphetamine self-administration in the rat.

RATIONALE: The circumstances of drug taking are thought to play a role in drug abuse but the evidence of it is anecdotal. Previous studies have shown that the intravenous self-administration of cocaine is facilitated in rats non-residing in the test chambers relative to rats that live in the test chambers at all times. We investigated here whether environmental context could exert its modulatory influence on heroin and amphetamine self-administration as well. MATERIALS AND METHODS: Independent groups of rats were given the possibility to self-administer different doses of heroin or amphetamine (12.5, 25.0, or 50.0 microg/kg). Some animals were housed in the self-administration chambers (resident groups) whereas other rats were transported to the self-administration chambers only for the test sessions (non-resident groups). RESULTS: Amphetamine-reinforcing effects were more pronounced in non-resident rats than in resident rats, as previously reported for cocaine. Quite unexpectedly, the opposite was found for heroin. Because of this surprising dissociation, some of the rats trained to self-administer amphetamine were later given the opportunity to self-administer heroin. Also in this case, resident rats took more heroin than non-resident rats. CONCLUSIONS: These findings suggest an unforeseen dissociation between opioid and psychostimulant reward and demonstrate that even in the laboratory rat some contexts are associated with the propensity to self-administer more opioid than psychostimulant drugs and vice versa, thus indicating that drug taking is influenced not only by economical or cultural factors but also can be modulated at a much more basic level by the setting in which drugs are experienced.

Seizure-Suppressant and Neuroprotective Effects of Encapsulated BDNF-Producing Cells in a Rat Model of Temporal Lobe Epilepsy.

Brain-derived neurotrophic factor (BDNF) may represent a therapeutic for chronic epilepsy, but evaluating its potential is complicated by difficulties in its delivery to the brain. Here, we describe the effects on epileptic seizures of encapsulated cell biodelivery (ECB) devices filled with genetically modified human cells engineered to release BDNF. These devices, implanted into the hippocampus of pilocarpine-treated rats, highly decreased the frequency of spontaneous seizures by more than 80%. These benefits were associated with improved cognitive performance, as epileptic rats treated with BDNF performed significantly better on a novel object recognition test. Importantly, long-term BDNF delivery did not alter normal behaviors such as general activity or sleep/wake patterns. Detailed immunohistochemical analyses revealed that the neurological benefits of BDNF were associated with several anatomical changes, including reduction in degenerating cells and normalization of hippocampal volume, neuronal counts (including parvalbumin-positive interneurons), and neurogenesis. In conclusion, the present data suggest that BDNF, when continuously released in the epileptic hippocampus, reduces the frequency of generalized seizures, improves cognitive performance, and reverts many histological alterations associated with chronic epilepsy. Thus, ECB device-mediated long-term supplementation of BDNF in the epileptic tissue may represent a valid therapeutic strategy against epilepsy and some of its co-morbidities.

Personalized Needles for Microinjections in the Rodent Brain.

Microinjections have been used for a long time for the delivery of drugs or toxins within specific brain areas and, more recently, they have been used to deliver gene or cell therapy products. Unfortunately, current microinjection techniques use steel or glass needles that are suboptimal for multiple reasons: in particular, steel needles may cause tissue damage, and glass needles may bend when lowered deeply into the brain, missing the target region. In this article, we describe a protocol to prepare and use quartz needles that combine a number of useful features. These needles do not produce detectable tissue damage and, being very rigid, ensure reliable delivery in the desired brain region even when using deep coordinates. Moreover, it is possible to personalize the design of the needle by making multiple holes of the desired diameter. Multiple holes facilitate the injection of large amounts of solution within a larger area, whereas large holes facilitate the injection of cells. In addition, these quartz needles can be cleaned and re-used, such that the procedure becomes cost-effective.

Modulatory effect of environmental context and drug history on heroin-induced psychomotor activity and fos protein expression in the rat brain.

The goal of the present study was to investigate the role of environmental context and drug history in modulating the effects of heroin on locomotor activity and Fos protein expression in the neocortex and striatal complex of the rat. It was found that (1) repeated i.p. administrations of a relatively low dose of heroin (1 mg/kg, i.p.) induced psychomotor sensitization only when the treatment was administered in a relatively 'novel' environment (ie, a unique test environment distinct from the home cage) but not when the same treatment was administered in the home cage; (2) environmental novelty facilitated heroin-induced Fos expression in the caudate, particularly in its most caudal regions; (3) environmental context also modulated heroin-induced Fos expression in the nucleus accumbens and in the neocortex; (4) repeated exposures to heroin dramatically altered its effects on Fos expression in the caudate and in the neocortex; and (5) Fos protein levels in the postero-dorsal caudate, in the shell of the nucleus accumbens, and in the barrel field cortex predicted most of the variance in heroin-induced activity scores, as shown by multiple regression analysis. The present report demonstrates that environment and drug history powerfully interact in shaping the neurobehavioral response to heroin, as previously shown for amphetamine and cocaine. Thus, a full understanding of the mechanisms responsible for the neurobehavioral adaptations produced by addictive drugs will also require taking into due consideration the environment in which drugs are experienced.