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The effects of transcranial magnetic stimulation (TMS), natalizumab (nata), dimethyl fumarate (DMF) and dexamethasone (DEX) on clinical score and oxidative stress produced by a single dose of myelin oligodendrocyte glycoprotein (MOG) in tail of Dark Agouti rats was studied. TMS (60 Hz and 0.7 mT), nata (5 mg/kg), DMF (15 mg/kg) and DEX (300 μg/kg) was applied for 21 after the administration of MOG (150 μg). We estimated clinical score, as well as lipid peroxides, carbonylated proteins and reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio content in brain, spinal cord and blood. MOG triggered significant increase in clinical score and in the levels of lipid peroxides and carbonylated proteins levels, but reduced GSH/GSSG ratio in brain, spinal cord and blood. Both TMS and clinical treatments, although TMS more significantly, decreased the changes caused by MOG administration. These results support the antioxidant and neuroprotective action of TMS, as well as an activity higher than other clinical treatments.

Olfactory glomeruli are the first synaptic site of the olfactory system and are formed by the convergence of axons of the same type of sensory neurons onto the olfactory bulbs of the brain. Although the anatomical organization of glomeruli is conserved across species, their particular role in olfactory processing remains uncertain. We studied the composition and maintenance of glomeruli by means of a genetic model, mI7-IRES-tauGFP knock-in young mice, where the cytoskeleton of sensory neurons expressing the mI7 olfactory receptor is tagged with green fluorescent protein. Animals were continuously exposed to heptaldehyde, a cognate ligand of the mI7 receptor, from postnatal days 5–10. We hypothesized that continuous odorant exposure will induce changes in glomerular morphology, and that this can be recovered if the normal odorant environment is reestablished within the early postnatal period. We assessed changes in the distribution of mI7 axons in glomerular morphology, as well as possible changes in the number of the mI7 olfactory sensory neurons. Following odorant exposure the well-defined convergence of mI7 fibers into a single glomerulus was disrupted, producing numerous neighboring glomeruli partially innervated by mI7 fibers. After the normal odor environment was reestablished the number of glomeruli partially innervated by mI7 fibers decreased significantly. Moreover, we found that multiple supernumerary mI7 glomeruli were formed. Our results confirm the significant role of sensory input in glomerular formation and maintenance. Additionally, we show that the developing olfactory system actively maintains glomerular morphology, suggesting the importance of this for olfactory processing.

Although not discernible at first glance, sleep is a highly active and regulated brain state. Although we spend practically one third of our lifetimes in this stage, its importance is often taken for granted. Sleep loss can lead to disease, error and economic loss. Our understanding of how sleep is achieved has greatly advanced in recent years, and with that, the management of sleep disorders has improved. There is still room for improvement and recently many new compounds have reached clinical trials with a few being approved for commercial use. Areas covered: In this review, the authors make the case of sleep disorders as a matter of public health. The mechanisms of sleep transition are discussed emphasizing the wake and sleep promoting interaction of different brain regions. Finally, advances in pharmacotherapy are examined in the context of chronic insomnia and narcolepsy. Expert opinion: The orexinergic system is an example of a breakthrough in sleep medicine that has catalyzed drug development. Nevertheless, sleep is a topic still with many unanswered questions. That being said, the melanin-concentrating hormone system is becoming increasingly relevant and we speculate it will be the next target of sleep medication.

Experimental autoimmune encephalomyelitis (EAE) reproduces a multiple sclerosis (MS)-like experimental model. The main objective was to evaluate the effect of extremely low-frequency electromagnetic fields (EL-EMF) application, like a paradigm of transcranial magnetic stimulation (TMS) in the development of EAE. Rats were injected with a single dose of 150 μg of myelin oligodendrocyte glycoprotein (MOG, fragment 35-55) to produce experimental MS. To assess the effect of TMS application in EAE, the rats were treated with TMS (60 Hz and 0.7 mT) for 2 h in the morning, once a day, 5 days a week, during 3 weeks. TMS was applied to the head. The effect of TMS on EAE was evaluated as motor symptoms and, oxidative and cell damage. The data showed that MOG induced motor symptoms as tail paralysis and limb paresis/paralysis, oxidative stress and cell death similar to MS when compared with control animals. Importantly, TMS application attenuated motor symptoms, oxidative and cell damage, whereas it increased antioxidant system. Our findings suggest that: (i) MOG reproduces an experimental model of MS characterised by oxidative and cell damage; and (ii) TMS application decreases oxidative stress and cell death induced by MOG.

The objective of the present study was to assess the benefits of 1-week repetitive transcranial magnetic stimulation (rTMS) in patients with chronic low back pain (LBP). The visual analogue scale (VAS), Short Form McGill pain questionnaire (SF-MPQ), and Short Form 36 Health Survey were used to evaluate the effect of this treatment. Eighty-two patients diagnosed with LBP were divided randomly into three groups: rTMS-treated group, sham group, and physical therapy-treated group. We observed a significant reduction in VAS and SF-MPQ scores in the rTMS-treated group, but not in the sham group. Moreover, patients who received rTMS had a lower mean pain score than patients treated with physical therapy. Our study suggests that rTMS produces safe, significant, and long-term relief in patients with LBP without evident side effects. This study shows for the first time that long-term repeated sessions of rTMS decrease pain perception of LBP. Bioelectromagnetics. 37:527-535, 2016. © 2016 Wiley Periodicals, Inc.

In the last decades, different transcranial magnetic stimulation protocols have been developed as a therapeutic tool against neurodegenerative and psychiatric diseases, although the biochemical, molecular and cellular mechanisms underlying these effects are not well known. Recent data show that those magnetic stimulation protocols showing beneficial effects could trigger an anti-oxidant action that would favour, at least partially, their therapeutic effect. We have aimed to review the molecular effects related to oxidative damage induced by this therapeutic strategy, as well as from them addressing a broader definition of the anti-oxidant concept.

Parkinson's disease is a neurodegenerative disease which often presents hyposmia (80-90% of the cases). We characterized the olfactory behavior in the model of 6-hydroxydopamine of Parkinson's disease. Mice were trained to discriminate between two odorants in a radial maze. One of the odorants was associated with water as a reward. 6-hydroxydopamine was injected directly into the dorsal striatum; after complete striatal denervation, olfactory performance was evaluated in a radial maze. In the first evaluation, experimental mice performed as control mice. After the first evaluation, the narine of the contralateral side to the striatal injection was closed and mice were evaluated again. The experimental group completely lost the capacity to discriminate between the odorant associated with the reward (heptaldehyde) and the unconditioned odorant (2-heptanone). We propose that the olfactory deficit was caused by dopaminergic denervation to the olfactory tubercle and nucleus accumbens.

Chromaffin cell transplants have been explored since the early 1980s as a promising alternative in different pathological states, mainly Parkinson's disease and chronic pain. Advances are significant since transplants have been performed in humans. The general mechanism of these transplants relies in the capacity of chromaffin cells to act as mini-pumps that release amines and peptides. Different strategies are being used to improve the efficacy of transplants. However, a remaining hurdle is to determine the viability across time and the interaction with the microenvironment of the graft. We analyzed previous and current results finding that although there is a lot of positive evidence, there is also a lack of molecular studies that support behavioral results. The present review gives an update on recent advances of chromaffin cell transplants and their future in the clinic.

In the present study, the effect of chromaffin cell transplant in the spinal cord was evaluated on formalin-induced mechanical secondary allodynia in the rat. Chromaffin cells were transplanted into the lumbar subarachnoid space before or after formalin injection. Subcutaneous formalin injection (50 μl, 1%) produced long-lasting secondary allodynia in the ipsilateral and contralateral hind paws. Once secondary allodynia was established, treatment with chromaffin cells produced a significant reduction in the nociceptive behavior in both hind paws. The antiallodynic effect was time-dependent since it was observed 15 days after chromaffin cell transplants but not before. On the other hand, pre-treatment with chromaffin cells prevented the expression of secondary allodynia in both hind paws in the rat. Antiallodynic effect of chromaffin cells was reverted with the non-selective opioid receptor antagonist naltrexone and the non-selective α 2 -adrenoceptor antagonist rauwolscine. Clusters of viable chromaffin cells labeled with anti-tyrosine hydroxylase antibodies were observed in the retrieved transplants 15 days after transplant. These results establish the analgesic efficacy of intrathecal chromaffin cells on formalin-induced secondary allodynia. Our data suggest that chromaffin cells release neuroactive substances including opioid peptides and adrenergic amines that reduce secondary allodynia in rats through activation of their receptors.

Orexins (hypocretins) are peptide neurotransmitters produced by a small group of neurons located exclusively in the lateral hypothalamus (LH). Orexins modulate arousal, and as a result, have profound effects on feeding behavior and the sleep-wake cycle. Loss of orexin producing neurons leads to a narcoleptic phenotype, characterized by sudden transitions from vigilance to rapid eye movement (REM) sleep (direct transition to REM, DREM) observed in electroencephalogram (EEG) and electromyogram (EMG) recordings. In this study, we demonstrate that mice lacking the basic helix-loop-helix transcription factor O/E3 (also known as ebf2) have a decrease in orexin-producing cells in the LH, in addition to a severely impaired orexinergic innervation of the pons. These changes in the orexinergic circuit of O/E3-null animals induce a narcoleptic phenotype, similar to the one arising in orexin-deficient and orexin-ataxin-3 mice. Taken together, our results suggest that O/E3 plays a central role during the establishment of a functional orexinergic circuit by controlling the expression of essential hypothalamic neurotransmitter and the correct development of the nerve fibers arising from the hypothalamus. This is the first report regarding the narcolepsy-cataplexy syndrome in O/E3-null mice, which adds the importance of transcription factors in the regulation of neural subpopulations that control the sleep-wake cycle.

The loss of dopaminergic neurons in the substantia nigra compacta followed by striatal dopamine depletion is a hallmark of Parkinson's disease. After dopamine depletion, dopaminergic D2receptor (D2R)-class supersensitivity develops in striatal neurons. The supersensitivity results in an enhanced modulation of Ca2+currents by D2R-class receptors. However, the relative contribution of D2R, D3R, and D4R types to the supersensitivity, as well as the mechanisms involved, have not been elucidated. In this study, whole cell voltage-clamp recordings were performed to study Ca2+current modulation in acutely dissociated striatal neurons obtained from rodents with unilateral 6-hydroxydopamine lesions in the substantia nigra compacta. Selective antagonists for D2R, D3R, and D4R types were used to identify whether the modulation by one of these receptors experiences a selective change after dopaminergic denervation. It was found that D3R-mediated modulation was particularly enhanced. Increased modulation targeted CaV2.1 (P/Q) Ca2+channels via the depletion of phosphatidylinositol 4,5-bisphosphate, an intracellular signaling cascade hard to detect in control neurons and hypothesized as being amplified by dopamine depletion. An imbalance in the striatal expression of D3R and its splice variant, D3nf, accompanied enhanced D3R activity. Because CaV2.1 Ca2+channels mediate synaptic GABA release from the terminals of striatal neurons, reinforcement of their inhibition by D3R may explain in part the profound decrease in synaptic strength in the connections among striatal projection neurons observed in the dopamine-depleted striatum.

Sleep deprivation (SD) produces numerous deleterious changes in brain cells, including apoptosis. It has been demonstrated that growth hormone (GH) stimulates cell growth and counteracts apoptosis, although this anti-apoptotic effect has not been tested against SD. To determine the protective effect of GH administration on cell proliferation and survival in the dentate gyrus (DG) of the hippocampus after sleep deprivation; we injected Wistar adult rats with a low dose of recombinant human GH (rhGH 5 ng/kg) per seven days and then we gently sleep deprived the animals for 48 consecutive hours. 5-Bromodeoxiuridine (BrdU) was administered to assess cell proliferation after the GH treatment and NeuN was used as marker of cell fate. Our results indicate that GH produced a three fold increase in the number of BrdU positive cells within the DG [Control = 1044 ± 106.38 cells, rhGH = 2952 ± 99.84 cells, P

Neuronal synchronization in basal ganglia circuits plays a key role in the encoding of movement, procedural memory storage and habit formation. Striatal dopamine (DA) depletion during Parkinsonism causes abnormal synchronization in corticobasal ganglia loops resulting in motor dysfunction. However, the dynamics of the striatal microcircuit underlying abnormal synchronization in Parkinsonism is poorly understood. Here we used targeted whole-cell recordings, calcium imaging allowing the recording from dozens of cells simultaneously and analytical approaches, to describe the striking alterations in network dynamics that the striatal microcircuit undergoes following DA depletion in a rat model of Parkinson disease (PD): In addition to a significant enhancement of basal neuronal activity frequent periods of spontaneous synchronization were observed. Multidimensional reduction techniques of vectorized network dynamics revealed that increased synchronization resulted from a dominant network state that absorbed most spontaneously active cells. Abnormal synchronous activity can be virtually abolished by glutamatergic antagonists, while blockade of GABAergic transmission facilitates the engagement of striatal cell assemblies in the dominant state. Finally, a dopaminergic receptor agonist was capable of uncoupling neurons from the dominant state. Abnormal synchronization and “locking” into a dominant state may represent the basic neuronal mechanism that underlies movement disorders at the microcircuit level.

We studied the effects of transcranial magnetic stimulation (TMS, 60 Hz and 0.7 mT for 4 h/day for 14 days) on oxidative and cell damage caused by olfactory bulbectomy (OBX) in Wistar rats. The levels of lipid peroxidation products and caspase-3 were enhanced by OBX, whereas it prompted a reduction in reduced glutathione (GSH) content and antioxidative enzymes activities. The treatment with TMS reverted towards normality the biomarkers indicative of oxidative stress and apoptosis. In conclusion, our data show that TMS induced a protection against cell and oxidative damage induced by OBX, as well as they support the hypothesis that oxidative stress may play an important role in depression.

We evaluated the effects of nicotine on cell and oxidative damage caused by olfactory bulbectomy (OBX). The rats were divided into seven groups as follows: i) control; ii) vehicle (6% ethanol); iii) treated with nicotine; iv) sham operated; v) olfactory bulbectomy (OBX); vi) OBX + vehicle; and vii) OBX + Nic. The OBX was performed using the trepanation of frontal bone. The olfactory bulbs were cut and removed without damage to the frontal cortex. Two weeks after surgery nicotine was administered chronically once daily for 14 days, intraperitoneally (i.p.) in doses of 1.5 mg/kg, two weeks after surgery. OBX caused an increase in lipid peroxidation products and caspase-3 but prompted a reduction in reduced glutathione (GSH) content and antioxidative enzyme activity. All these changes were reverted by treatment of nicotine (14 days). In conclusions: i) OBX induces oxidative stress and cell death by apoptosis; and ii) nicotine presents antidepressant and antioxidant effect. All these findings suggest that nicotine would be a therapeutic tool for depression, although more studies are needed in this area to define the appropriate treatment regime.

In this study, we compared the depression-like symptoms induced by olfactory bulbectomy (OBX) in the two inbred Wistar and Long Evans rat strains. We also analyzed the self-regulated oral intake of nicotine in these strains and the effect of nicotine on the depression-like symptoms of olfactory bulbectomy. Furthermore, we compared the antidepressant-like effects of nicotine on Wistar rats to those of transcranial magnetic stimulation (TMS), which has emerged as a therapeutic alternative for depression management. Our results show that Wistar rats develop depression-like symptoms, demonstrated by the forced swim test (FST), 4 weeks after OBX. However, in bulbectomized Long Evans rats these symptoms cannot be assessed due to a higher degree of variability of the swimming behavior of this strain. These results suggest that there are some innate differences in susceptibility to stress between these two rat strains. In Wistar rats, voluntary oral nicotine intake (1.2 mg/(kg day) for 14 days) as well as nicotine administered as a single daily i.p. injection (1.5 mg/(kg day) for 14 days) decrease the depression-like symptoms of OBX. Daily transcranial magnetic stimulation (60 Hz and 0.7 mT for 2h/day for 14 days) also decreases depression-like symptoms but is less effective than nicotine. In conclusion, our results support the idea that there are possible innate differences for depression susceptibility and that nicotine and TMS may be useful in the treatment of this syndrome.

Very few neurons in the telencephalon have been shown to express functional postsynaptic nicotinic acetylcholine receptors (nAChRs), among them, the noradrenergic and dopaminergic neurons. However, there is no evidence for postsynaptic nAChRs on serotonergic neurons. In this study, we asked if functional nAChRs are present in serotonergic (5-HT) and nonserotonergic (non-5-HT) neurons of the dorsal raphe nucleus (DRN). In rat midbrain slices, field stimulation at the tegmental pedunculopontine (PPT) nucleus evoked postsynaptic currents (eEPSCs) with different components in DRN neurons. After blocking the glutamatergic and GABAergic components, the remaining eEPSCs were blocked by mecamylamine and reduced by either the selective alpha7 nAChR antagonist methyllycaconitine (MLA) or the selective alpha4beta2 nAChR antagonist dihydro-beta-eritroidine (DHbetaE). Simultaneous addition of MLA and DHbetaE blocked all eEPSCs. Integrity of the PPT-DRN pathway was assessed by both anterograde biocytin tracing and antidromic stimulation from the DRN. Inward currents evoked by the direct application of acetylcholine (ACh), in the presence of atropine and tetrodotoxin, consisted of two kinetically different currents: one was blocked by MLA and the other by DHbetaE; in both 5-HT and non-5-HT DR neurons. Analysis of spontaneous (sEPSCs) and evoked (eEPSCs) synaptic events led to the conclusion that nAChRs were located at the postsynaptic membrane. The possible implications of these newly described nAChRs in various physiological processes and behavioral events, such as the wake-sleep cycle, are discussed.

Few studies have evaluated the impact of smoking cessation on objective measures of sleep. The present study assessed the long-term effects of tobacco smoking abstinence on sleep and depression. A total of 15 chronic smokers with Hamilton Rating Scale for Depression (HAM-D) scores of less than 9 were evaluated. Subjects were screened for baseline data when they were smoking chronically. They underwent a 5-week psychological treatment for tobacco smoking, after which their depressive symptoms and sleep architecture were evaluated at 1, 2, 4, 6, 9, and 12 months of abstinence. We report the results of the seven patients who completed 1 year of evaluations and of those patients who achieved only partial abstinence. Polysomnographic recordings were taken, level of depression was measured with the HAM-D, and urinary cotinine levels also were evaluated. HAM-D scores were analyzed with and without sleep items. Nicotine abstinence reduced latency to rapid eye movement (REM) sleep and increased HAM-D scores, suggesting that chronic smokers have depressive symptoms that may be controlled by nicotine administration.

An investigation was conducted on the effect of transcranial magnetic field stimulation (TMS) on the free radical production and neuronal cell loss produced by 3-nitropropionic acid in rats. The effects of 3-nitropropionic acid were evaluated by examining the following changes in: the quantity of hydroperoxides and total radical-trapping antioxidant potential (TRAP), lipid peroxidation products, protein carbonyl groups, reduced glutathione (GSH) content, glutathione peroxidase (GSH-Px), catalase and succinate dehydrogenase (SDH) activities; total nitrite and cell death [morphological changes, quantification of neuronal loss and lactate dehydrogenase (LDH) levels]. Our results reveal that 3-nitropropionic acid induces oxidative and nitrosative stress in the striatum, prompts cell loss and also shows that TMS prevents the harmful effects induced by the acid. In conclusion, the results show the ability of TMS to modify neuronal response to 3-nitropropionic acid.

In this paper, the effect of nicotine on the oxidative changes produced by 3-nitropropionic acid (20 mg/kg i.p./day for 4 days) in striatal and cortical synaptosomes of Wistar rats was studied. The effects of 3-nitropropionic acid were evaluated as changes in the quantity of protein carbonyl groups, lipid peroxidation products, superoxide distumase activity and reduced succinate dehydrogenase activity. All changes were prevented by the pre-injection of nicotine (1.5 mg/kg i.p./day), beginning 4 days before and continuing for 4 days after the first injection of 3-nitropropionic acid. These findings indicate that: (i) 3-nitropropionic acid induces a state of oxidative stress in cortical and striatal synaptosomes and (ii) nicotine prevents oxidative stress induced by 3-nitropropinonic acid. In conclusion, the results show the ability of nicotine to modify neural response to 3-nitropropionic acid with the protective mechanism likely involving the antioxidative processes of nicotine.

Yawning, a phylogenetic behavior, present in reptiles, birds and mammals, has been studied for several decades, but to date its physiological function is still unknown. The role of stress as well as several peptides and the hypothalamus has been studied in relation to its regulation. To date however, no studies has been carried out to determine the role of the adrenal glands. Therefore, yawning behavior was studied in adrenalectomized rats, who then received dexamethasone replacement. The results show that rats whose adrenal glands were removed stopped both spontaneous and apomorphine-induced yawning, while dexamethasone reverted this effect. The results are discussed in terms of the possible role of corticosterone on yawning behavior.

Neurogenesis continues at least in two regions of the mammalian adult brain, the subventricular zone (SVZ) and the subgranular zone in hippocampal dentate gyrus. Neurogenesis in these regions is subjected to physiological regulation and can be modified by pharmacological and pathological events. Here we report the induction of neurogenesis in the SVZ and the differentiation after nigrostriatal pathway lesion along with transcranial magnetic field stimulation (TMFS) in adult rats. Significant numbers of proliferating cells demonstrated by bromodeoxyuridine-positive reaction colocalized with the neuronal marker NeuN were detected bilaterally in the SVZ, and several of these cells also expressed tyrosine hydroxylase. Transplanted chromaffin cells into lesioned animals also induced bilateral appearance of subependymal cells. These results show for the first time that unilateral lesion, transplant, and/or TMFS induce neurogenesis in the SVZ of rats and also that TMFS prevents the motor alterations induced by the lesion.

Transcranial magnetic stimulation (TMS) is a non-invasive technique used recently to treat different neuropsychiatric and neurodegenerative disorders. Despite its proven value, the mechanisms through which TMS exerts its beneficial action on neuronal function remain unclear. Recent studies have shown that its beneficial effects may be at least partly due to a neuroprotective effect on oxidative and cell damage. This study shows that TMS can modulate the Nrf2 transcriptor factor in a Huntington's disease-like rat model induced by 3-nitropropionic acid (3-NP). Western blot analysis demonstrated that 3-NP caused a reduction in Nrf2 in both cytoplasm and nucleus, while TMS applied to 3-NP-treated rats triggered an increase in cytoplasm and nucleus Nrf2 levels. It was therefore concluded that TMS modulates Nrf2 expression and translocation and that these mechanisms may partly explain the neuroprotective effect of TMS, as well as its antioxidant and cell protection capacity.

Prism adaptation is a form of visuomotor learning in which the visual and motor systems need to be adjusted because a visual perturbation is produced by horizontally displacing prisms. Despite being known for over two centuries, the neuronal substrates of this phenomenon are not yet completely understood. In this article the possible role of the basal ganglia in this kind of learning was analysed through a study of Huntington's and Parkinson's disease patients. A throwing technique requiring the use of open loop feedback was used. The variables analysed were visuomotor performance, adaptation rate and magnitude, and the after-effect. The results clearly showed that both Huntington's and Parkinson's disease groups learned at the same rate as control subjects. In addition, despite having a disturbed visuomotor performance, both experimental groups showed the same adaptation magnitude as the control group. Finally, the after-effect, which is measured after removing the prisms, is reduced in both patients groups. This reduction leads to a disruption in the normal adaptation-after-effect correlation found in normal volunteers. These results suggest that basal ganglia are not involved in this type of open-looped visuomotor learning. The large number of patients studied as well as the similarity of the findings between both populations support this hypothesis. By contrast, there is an impairment in the after-effect on both basal ganglia patient populations. This impairment may be the result of the deterioration of the perceptual recalibration process involved in visuomotor learning.

Clinical studies suggest that depression facilitates alcohol abuse. Depressed individuals also have increased rates of smoking, and it has been suggested that nicotine may improve depression. It is therefore possible that nicotine may reduce alcohol use in depression. To investigate this potential relationship, we evaluated alcohol intake in an animal model of depression, which consists of administering clomipramine (CLI), a preferential serotonin reuptake inhibitor, to neonatal rats. This pharmacological manipulation produces adult depression-like behaviors, such as reduced aggressiveness, decreased pleasure seeking, diminished sexual activity, increased locomotor activity and increased REM sleep. In this study, we found that CLI rats exhibited significantly higher locomotor activity, lower aggressiveness and higher alcohol intake than control rats. Chronic administration of a low dose of nicotine (0.25 mg/kg/day) or a sham operation did not modify these behaviors. However, chronic administration of nicotine at a higher dose (1.5 mg/kg/day) significantly increased aggressive behavior and reduced alcohol intake in CLI rats. The effect of nicotine on alcohol intake lasted at least 1 month after cessation of nicotine administration. These results indicate that nicotine reverted some depression signs and reduced alcohol self-administration in the CLI model of depression.

The results reported herein address the question of synaptogenesis between adrenal chromaffin cells and striatal neurons. The release of dopamine from chromaffin cells in the presence of striatal neurons was also examined. Co-culture of newborn rat chromaffin cells and striatal neurons at 1:1 ratio was made. Cultures were examined morphologically using immunocytochemistry and ultrastructural techniques (transmission electron microscopy), while quantitation of dopamine in the culture media by HPLC-ECD was also determined. Neurite outgrowth from chromaffin cells was enhanced in the presence of striatal neurons and numerous synaptic-like contacts between these two cell types were observed. Higher concentration of dopamine was also present in the co-culture medium as compared with those containing only chromaffin cells. The development of synapses between these two types of cells may give support to the functionality of transplants in human cases of Parkinson disease (PD).

The application of nerve growth factor (NGF) to primary adrenal medulla chromaffin cell cultures induces phenotypic changes characterized mainly by the presence of neurites. A similar effect has been seen when these cells are stimulated by extremely low frequency magnetic fields (ELFMF). In this study, newborn rat chromaffin cells were cultured and subjected to NGF or ELFMF in order to compare their histological and ultrastructural characteristics. Cells cultured in the presence of NGF developed cytoplasmic projections and their distal ends showed growth cones as well as filopodia. With scanning and transmission electron microscopy, an increased submembranous electron density was observed in the nuclei of cells as well as irregular, wavy neuritic projections with a moderate number of varicosities, as well as the prevalence of intermediate filaments among the cytoskeleton components. Cells stimulated with ELFMF presented straighter neuritic extensions with a greater number of varicosities. With the transmission electron microscope, numerous neurotubules were observed, both in the cell soma and in their neuritic extensions. In both groups, growth cones were clearly identified by their ultrastructural characteristics. The differences seen in the cytoskeleton of cells stimulated with NGF or ELFMF suggest differential stimulation mechanisms possibly determining the biochemical, electrophysiological, and morphological characteristics in both types of cell cultures. J. Neurosci. Res. 53:569–582, 1998. © 1998 Wiley-Liss, Inc.

Previous experiments have demonstrated that auditory (AS) and/or somatosensory (SS) stimulation can increase the duration of REM sleep periods in rats, cats and humans. The objectives of this study were to determine whether repeated AS stimulation causes habituation to the stimulus and whether any additive effects could be obtained with the simultaneous application of AS and SS. Three experimental procedures were used in this study. In experiment 1, animals were recorded for 4 consecutive days with AS, followed by a post-stimulus session. In experiment 2, they were recorded for 24 hours with AS applied at each REM period, followed by a subsequent 24-hours-post-stimulus recording. In experiment 3, animals underwent AS, SS stimulation, or simultaneous application of both in a random fashion at each REM period. The results of all experiments confirm previous findings showing that auditory or somatosensory stimuli significantly increase REM sleep period duration. In addition, AS--applied with different presentations during REM and throughout the sleep-wake cycle--are capable of increasing REM duration regardless of the manner in which they were presented. However, the effects of the stimuli were not additive. It is worth noting that although REM duration increased, REM period frequency decreased, resulting in no net change of total REM sleep through time. Furthermore, no changes were observed in other sleep-wake variables. These experiments clearly demonstrate that repeated auditory stimulation does not cause habituation, and there are no evident side effects on the sleep-wake cycle. These results confirm that the mechanisms involved in REM generation and maintenance can be modulated by sensory modalities.

The role of repeated nicotine administration on sleep and major depression was studied. Six non-smoking normal volunteers (NV) and six non-smoking major depressed patients (MD) with a Hamilton Rating Scale for Depression > 18 served as subjects. All subjects underwent the following sleep procedures: acclimatization, control night, four nicotine nights (17.5 mg, transdermal patches) and one withdrawal night (WN). Nicotine increased REM sleep time in both groups and also on the WN. Hamilton scores showed an average reduction of 43.9% in the depressed patients. These findings suggest that nicotine receptor activation may be important in major depression and shows for the first time that nicotine patches may be useful in the treatment of depression.

Major depression is characterized by a diminished activity of the brain serotonergic system as well as by the flattening of plasma cortisol levels. Nicotine improves mood in patients with major depression and in experimentally depressed animals by increasing brain serotonin (5-HT), noradrenaline and dopamine levels. The present study was directed to determine if flattening plasma glucocorticoid levels changes nicotine's stimulatory effects upon 5-HT DRN neurons. The experiments were performed in brain slices obtained from rats previously (14 days) adrenalectomised and implanted subcutaneously with one pellet containing 75mg of corticosterone (Adx+CSR rats). Whole cell voltage and current clamp techniques were used to study the activity of immunocitochemically identified 5-HT DRN neurons. Administration of nicotine (1μM) in sham-operated animals produced stimulatory effects in all 5-HT DRN neurons studied. In Adx+CSR rats however, nicotine inhibited 75% of 5-HT DRN neurons and increased the potassium-dependent inward rectifying current. The inhibitory effect of nicotine upon 5-HT DRN neurons was dependent on serotonin release inside the DRN, since it was converted into a stimulatory response by the selective antagonist of 5-HT1A receptors N-[2-[4-(2-methoxyphenyl)-1-piperazinyl]ethyl]-N-(2-pyridyl)cyclohexanecarboxamide (WAY100635, 25nM). Adx+CSR rats also presented an increased function of 5-HT1A autoreceptors, since, in these rats, serotonin (1-10μM) produced a higher increase in the potassium dependent inward rectifying current in comparison with sham-operated animals. Serotonin release inside DRN was mediated by α4β2 nicotinic acetylcholine receptors since the selective antagonist of these receptors dihydro-β-erytroidine hydrobromide (DHβE, 100nM) blocked the inhibitory effects of nicotine 5-HT DRN neurons. These data indicate that, in the experimental model of adrenalectomised rats implanted with corticosterone pellets, nicotine increases the function of 5-HT1A receptors of 5-HT DRN neurons.

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra pars compacta (SNc) and its projections. Reports show a lower incidence of PD in smokers compared to nonsmokers. Nicotine reduce motor symptoms of patients already diagnosed with PD. However, the mechanisms underlying the effects of nicotine in the dopamine (DA) depleted striatum remain elusive. This study evaluates the effects of chronic nicotine administration on PD motor symptoms in an attempt to mimic the chronic self-administration of nicotine in smokers. To achieve this, we used the 6-OHDA hemiparkinson rat model evaluating the amphetamine/apomorphine induced circling behavior, in rats whose daily water intake included nicotine. We found that chronic nicotine reduced amphetamine (AMPH) induced circling behavior by 40%, whereas apomorphine (APO) increased this behavior by 230%. High-performance liquid chromatography (HPLC) revealed that AMPH produced a 50% decrease of DA release in the intact hemisphere, while on the striatum of the lesioned side, receptor binding assays showed an increased affinity to D1 receptors and a concurrent decrease in D2 receptors. c-Fos activity showed through double labeling, that cell types involved in nicotine action were low threshold (LTS) and fast spiking (FS) inter-neurons, which increased in the DA-depleted striatum. We also observed an increase in the activity of D1 medium spiny neurons (D1 MSN), a striatal population with a major role in motor control. Our results show that chronic nicotine does not specifically protect against degeneration, but rather modifies DA receptor dynamics, suggesting that it could be used as a therapeutic element in PD pathology.

It is accepted that sensory experience instructs the remodelling of neuronal circuits during postnatal development, after their specification has occurred. The story is less clear with regard to the role of experience during the initial formation of neuronal circuits, whether prenatal or postnatal, since this process is now supposed to be primarily influenced by genetic determinants and spontaneous neuronal firing. Here we evaluated this last issue by examining the effect that postnatal chronic exposure to cognate odorants has on the formation of I7 and M72 glomeruli, iterated olfactory circuits that are formed before and after birth, respectively. We took advantage of double knock-in mice whose I7 and M72 primary afferents express green fluorescent protein and β-galactosidase, correspondingly. Our results revealed that postnatal odorant chronic exposure led to the formation of permanent supernumerary I7 and M72 glomeruli in a dose and time dependent manner. Glomeruli in exposed mice were formed within the same regions of olfactory bulb and occupy small space volumes compared to the corresponding single circuits in non-exposed mice. We suggest that local reorganization of the primary afferents could participate in the process of formation of supernumerary glomeruli. Overall, our results support that sensory experience indeed instructs the permanent formation of specific glomeruli in the mouse olfactory bulb by means of constructivist processes.

Narcolepsy is a sleep disorder characterized by excessive daytime sleepiness, inadvertent transitions from wakefulness to rapid eye movement sleep (so called "sleep-onset REMS period") and cataplexy (sudden bilateral skeletal muscle weakness during waking without impairment of consciousness). This disorder has been recently linked to a loss of hypocretin (HCRT) neurons making narcolepsy a neurodegenerative disease. Neuronal replacement could be used to reverse the symptoms of narcolepsy. Towards this end, we have recently reported that HCRT neurons from rat pups can survive when grafted into the pons of adult rats. Here, we investigate the time-course of survival of grafted HCRT neurons into the pons of adult rats. The HCRT neurons are present only in the lateral hypothalamus, and therefore suspension of cells from this region was derived from 8- to 10-day-old rat pups (donor), and grafted into the pons of adult (60 days old) host rats. Control rats received a transplant that consisted of cells from the cerebellum where no HCRT neurons are present. All adult host rats were sacrificed 1, 3, 6, 9, 12, 24, or 36 days after grafting. Immunohistochemistry was used to identify and count the presence of the HCRT grafted neurons in the target area. The tally of HCRT neurons present in the graft zone 1 day post-grafting was considered to be the baseline. From day 3 to 36 post-transplant there was a steady decline in the number of HCRT neurons. We also noted that on day 36, the HCRT neurons that survived in the pons had morphological features that were similar to mature HCRT neurons in the adult lateral hypothalamus, suggesting that these neurons might be functionally active. Control rats that received grafts of cerebellar tissue did not show HCRT neurons in the target area. These results demonstrate that there is a progressive decline in the number of transplanted neurons, but a significant percentage of HCRT neurons do survive until day 36. This study highlights the potential use of transplants as a therapeutical tool in order to treat narcolepsy.

1. Parkinson's disease (PD) is a neurodegenerative disorder caused by the loss of neurons in the substantia nigra pars compacta and a striatal deficiency of dopamine. PD typically affects people in late middle age and progresses slowly. In the early stages of the disease, treatment targeting the dopaminergic network is effective. However, with disease progression, transplantation is an option for repairing and replacing missing dopaminergic neurons. 2. In this review, we evaluate the tissue grafts and cellular therapies that have and are being considered. Clinical trials were originally derived from transplants of adrenal medullary chromaffin cells and embryonic nigral dopaminergic neurons in patients with PD. 3. Recently, novel molecular and cellular treatments are being utilized in animals and these include embryonic stem cells, fetal cells from pigs, or transfected cells. In spite of new molecular techniques and some 20 years of experience, the transplantation therapy for PD has today the same problems and results as the first reports which used neural fetal tissue or adrenal grafts.

Neurophysiological and biochemical mechanisms regulating REM sleep episodes were studied in behaving cats with chronic electrodes. Push-pull perfusion of the midbrain or pontine reticular formation (RF) by a protein synthesis inhibitor, chloramphenicol (CAP), reduced neuronal unit discharge, particularly discharge bursts, within the perfused area, and reduced the incidence of sustained REM periods. During transitions to "aborted" as compared to sustained REM episodes. RF unit discharge was reduced, under all conditions. In 72-hour sleep deprived cats, systemic injections of both atropine (ATR) and CAP attenuated REM rebound, but with different patterns. CAP reduced REM episode frequency. ATR reduced REM duration. ATR also reduced PGO wave frequency. Combined CAP and ATR treatment produced additive REM depressant effects. These data suggest that cholinergic mechanisms regulate PGO activity and maintenance of REM episodes and that protein synthesis-dependent mechanisms regulate RF unit discharge bursts, and REM triggering.

The present investigation sought to determine the effects of Anisomycin (A), Chloramphenicol (ChA), Vincristine (V), and Penicilline G on the sleep-wake cycle of rats. It was found that both high and low doses of anisomycin decreased rapid eye movement (REM) sleep, while only high doses of ChA and V produced such a decrease. Slow wave sleep (SWS) was unaffected by these drugs. Penicilline G, on the other hand, had no effect on the sleep-wake cycle. It was further shown that the reduction of REM sleep was the result of a decrease in the number of REM periods rather than in the duration of each individual period. These results suggest that protein synthesis may participate in the mechanisms that trigger REM sleep.

Delta(9)-tetrahydrocannabinol (Delta(9)-THC) and cannabidiol (CBD) are two major constituents of Cannabis sativa. Delta(9)-THC modulates sleep, but no clear evidence on the role of CBD is available. In order to determine the effects of CBD on sleep, it was administered intracerebroventricular (icv) in a dose of 10 microg/5 microl at the beginning of either the lights-on or the lights-off period. We found that CBD administered during the lights-on period increased wakefulness (W) and decreased rapid eye movement sleep (REMS). No changes on sleep were observed during the dark phase. Icv injections of CBD (10 microg/5microl) induced an enhancement of c-Fos expression in waking-related brain areas such as hypothalamus and dorsal raphe nucleus (DRD). Microdialysis in unanesthetized rats was carried out to characterize the effects of icv administration of CBD (10 microg/5 microl) on extracellular levels of dopamine (DA) within the nucleus accumbens. CBD induced an increase in DA release. Finally, in order to test if the waking properties of CBD could be blocked by the sleep-inducing endocannabinoid anandamide (ANA), animals received ANA (10 microg/2.5 microl, icv) followed 15 min later by CBD (10 microg/2.5 microl). Results showed that the waking properties of CBD were not blocked by ANA. In conclusion, we found that CBD modulates waking via activation of neurons in the hypothalamus and DRD. Both regions are apparently involved in the generation of alertness. Also, CBD increases DA levels as measured by microdialysis and HPLC procedures. Since CBD induces alertness, it might be of therapeutic value in sleep disorders such as excessive somnolence.

We describe the pre- and postoperative neuropsychological profiles of seven patients who received an autograft of adrenal medullary tissue to the caudate nucleus for the treatment of Parkinson9s Disease (PD). The preoperative neuropsychological evaluations revealed specific cognitive deficits of varying degree. The patients showed frontal lobe-type deficits with alterations in behavioral programming leading to difficulties in the organization of motor sequences and alternating programs. They also showed memory disorders and visuospatial and visuoperceptual deficiences such as a loss of figure-ground perspective and fragmentation. Postoperative evaluations, carried out 3 months after neurosurgery, revealed a significant amelioration of the frontal lobe-type symptoms and visuospatial deficits, as well as an improvement in memory tasks that require an active organization of the response. Immediate and delayed memory difficulties remained unchanged. These observations were compared to neuropsychological data obtained from neurologically intact subjects and from unoperated PD patients. The improvements of the operated PD patients resulted in performance levels close to normal values and clearly distinguishable from those of unoperated PD patients, and were unrelated to improved mood, increased alertness, or sustained attention. Auto-transplantation of adrenal medullary tissue to the caudate nucleus of PD patients showing a decreased effective response to l-dopa therapy can partially restore motor functions and frontal-type cognitive symptoms.

Background Previous work showed differences in the polysynaptic activation of GABAergic synapses during corticostriatal suprathreshold responses in direct and indirect striatal projection neurons (dSPNs and iSPNs). Here, we now show differences and similarities in the polysynaptic activation of cortical glutamatergic synapses on the same responses. Corticostriatal contacts have been extensively studied. However, several questions remain unanswered, e.g.: what are the differences and similarities in the responses to glutamate in dSPNs and iSPNs? Does glutamatergic synaptic activation exhibits a distribution of latencies over time in vitro? That would be a strong suggestion of polysynaptic cortical convergence. What is the role of kainate receptors in corticostriatal transmission? Current-clamp recordings were used to answer these questions. One hypothesis was: if prolonged synaptic activation distributed along time was present, then it would be mainly generated from the cortex, and not from the striatum. Results By isolating responses from AMPA-receptors out of the complex suprathreshold response of SPNs, it is shown that a single cortical stimulus induces early and late synaptic activation lasting hundreds of milliseconds. Prolonged responses depended on cortical stimulation because they could not be elicited using intrastriatal stimulation, even if GABAergic transmission was blocked. Thus, the results are not explained by differences in evoked inhibition. Moreover, inhibitory participation was larger after cortical than after intrastriatal stimulation. A strong activation of interneurons was obtained from the cortex, demonstrating that polysynaptic activation includes the striatum. Prolonged kainate (KA) receptor responses were also elicited from the cortex. Responses of dSPNs and iSPNs did not depend on the cortical area stimulated. In contrast to AMPA-receptors, responses from NMDA- and KA-receptors do not exhibit early and late responses, but generate slow responses that contribute to plateau depolarizations. Conclusions As it has been established in previous physiological studies in vivo, synaptic invasion over different latencies, spanning hundreds of milliseconds after a single stimulus strongly indicates convergent polysynaptic activation. Interconnected cortical neurons converging on the same SPNs may explain prolonged corticostriatal responses. Glutamate receptors participation in these responses is described as well as differences and similarities between dSPNs and iSPNs.