Cell Cycle Activation and Spinal Cord Injury

Traumatic spinal cord injury (SCI) evokes a complex cascade of events with initial mechanical damage leading to secondary injury processes that contribute to further tissue loss and functional impairment. Growing evidence suggests that the cell cycle is activated following SCI. Up-regulation of cell cycle proteins after injury appears to contribute not only to apoptotic cell death of postmitotic cells, including neurons and oligodendrocytes, but also to post-traumatic gliosis and microglial activation. Inhibition of key cell cycle regulatory pathways reduces injury-induced cell death, as well as microglial and astroglial proliferation both in vitro and in vivo. Treatment with cell cycle inhibitors in rodent SCI models prevents neuronal cell death and reduces inflammation, as well as the surrounding glial scar, resulting in markedly reduced lesion volumes and improved motor recovery. Here we review the effects of SCI on cell cycle pathways, as well as the therapeutic potential and mechanism of action of cell cycle inhibitors for this disorder.     

Endogenous Repair after Spinal Cord Contusion Injuries in the Rat

Contusion injuries of the rat thoracic spinal cord were made using a standardized device developed for the Multicenter Animal Spinal Cord Injury Study (MASCIS). Lesions of different severity were studied for signs of endogenous repair at times up to 6 weeks following injury. Contusion injuries produced a typical picture of secondary damage resulting in the destruction of the cord center and the chronic sparing of a peripheral rim of fibers which varied in amount depending upon the injury magnitude. It was noted that the cavities often developed a dense cellular matrix that became partially filled with nerve fibers and associated Schwann cells. The amount of fiber and Schwann cell ingrowth was inversely related to the severity of injury and amount of peripheral fiber sparing. The source of the ingrowing fibers was not determined, but many of them clearly originated in the dorsal roots. In addition to signs of regeneration, we noted evidence for the proliferation of cells located in the ependymal zone surrounding the central canal at early times following contusion injuries. These cells may contribute to the development of cellular trabeculae that provide a scaffolding within the lesion cavity that provides the substrates for cellular infiltration and regeneration of axons. Together, these observations suggest that the endogenous reparative response to spinal contusion injury is substantial. Understanding the regulation and restrictions on the repair processes might lead to better ways in which to encourage spontaneous recovery after CNS injury.     

Neuronal Apoptosis and Necrosis Following Spinal Cord Ischemia in the Rat

We examined the characteristics of neuronal death induced by ischemia in the spinal cord. Spinal cord ischemia was induced in Long–Evans rats by occlusion of the descending aorta with a 2F Fogarty catheter for 20 min (model 1) or more limited aortic occlusion (15 min) coupled with blood volume reduction (model 2); rats were sacrificed 6 h–7 days later. The animals developed variable paraparesis in model 1 and reliable paraplegia in model 2. The extent of histopathological spinal cord damage, being maximal in the lumbar cord, correlated well with the severity of paraparesis. Two distinct types of spinal cord neuronal death were observed, consistent with necrosis and apoptosis. Neuronal necrosis was seen in gray matter laminae 3–7, characterized by the rapid (6 h) onset of eosinophilia on hematoxylin/eosin-stained sections, and gradual (1–7 days) development of eosinophilic ghosting. Although TUNEL positivity was present, disintegration of membranes and cytoplasmic organelles was seen under electron microscopy. Neuronal apoptosis was seen after 1–2 days in dorsal horn laminae 1–3, characterized by both TUNEL positivity and electron microscopic appearance of nuclear chromatin aggregation and the formation of apoptotic bodies. DNA extracted from the ischemic lumbar cord showed internucleosomal fragmentation (laddering) on gel electrophoresis. These data suggest that distinct spinal cord neuronal populations may undergo necrosis and apoptosis following transient ischemic insults.     

Chemokine Receptor CXCR3 in the Spinal Cord Contributes to Chronic Itch in Mice

Recent studies have shown that the chemokine receptor CXCR3 and its ligand CXCL10 in the dorsal root ganglion mediate itch in experimental allergic contact dermatitis(ACD). CXCR3 in the spinal cord also contributes to the maintenance of neuropathic pain. However,whether spinal CXCR3 is involved in acute or chronic itch remains unclear. Here, we report that Cxcr3~(-/-) mice showed normal scratching in acute itch models but reduced scratching in chronic itch models of dry skin and ACD. In contrast, both formalin-induced acute pain and complete Freund's adjuvant-induced chronic inflammatory pain were reduced in Cxcr3~(-/-) mice. In addition, the expression of CXCR3 and CXCL10 was increased in the spinal cord in the dry skin model induced by acetone and diethyl ether followed by water(AEW). Intrathecal injection of a CXCR3 antagonist alleviated AEW-induced itch. Furthermore, touch-elicited itch(alloknesis) after compound 48/80 or AEW treatment was suppressed in Cxcr3~(-/-) mice.Finally, AEW-induced astrocyte activation was inhibited in Cxcr3~(-/-)mice. Taken together, these data suggest that spinal CXCR3 mediates chronic itch and alloknesis, and targeting CXCR3 may provide effective treatment for chronic pruritus.     

Translocation Associated Membrane Protein 1 Contributes to Chronic Constriction Injury-Induced Neuropathic Pain in the Dorsal Root Ganglion and Spinal Cord in Rats

Neuropathic pain is a severe debilitating state caused by injury or dysfunction of somatosensory nervous system, and the clinical treatment is still challenging. Translocation associated membrane protein 1 (TRAM1), an adapter protein, participates in a variety of transduction pathways and mediates the biological functions such as cell proliferation, activation, and differentiation. However, whether TRAM1 is involved in the pathogenesis of neuropathic pain is still unclear. In our study, we reported the role of TRAM1 in the maintenance of neuropathic pain induced by chronic constriction injury (CCI) on rats. By western blot and staining, we found that TRAM1 increased in the dorsal root ganglion (DRG) neurons and spinal cord (SC) neurons after CCI. Being similar to IB4-, CGRP-positive expressed area, TRAM1 also expressed in the superficial laminae of the spinal cord dorsal horn (SCDH), suggesting it was related to the innervations of the primary afferents. Moreover, intrathecal injection of TRAM1 siRNA or Toll-like receptor 4 (TLR4) inhibitor induced low expression of TRAM1 in SC, which alleviated the pain response induced by CCI. The upregulation of p-NF-κB expression was reversed by TRAM1 siRNA in SC and DRG, and intrathecal injection of p-NF-κB inhibitor relieved neuropathic pain. All the data indicated that TRAM1 could take part in CCI-induced pain and might be a potential treatment for chronic neuropathic pain.     

Ultrastructural Changes in the Rat Phrenic Nucleus Developing within 2 h after Cervical Spinal Cord Hemisection

The present study was conducted to describe the ultrastructural changes which occur in the young adult rat phrenic nucleus within 2 h after an ipsilateral C2 spinal cord hemisection. The main objective was to determine if there is a temporal relationship between specific ultrastructural changes in the phrenic nucleus and a significant augmentation of crossed phrenic nerve activity which occurs as early as 2 h after hemisection. Phrenic motoneurons were identified at electron microscopic levels by retrograde HRP labeling. Ultrastructural features in the phrenic nucleus of control and experimental rats were qualitatively analyzed and then quantitated. At 2 h posthemisection, there was a significant increase in the mean percentage of phrenic dendrodendritic appositions. In the control rats, 4.73 ± 0.18% of phrenic dendrites were in apposition, and this percentage increased significantly to 8.58 ± 0.54% at 2 h after injury. Furthermore, the mean lengths of asymmetrical and symmetrical synaptic active zones increased significantly at 2 h posthemisection from control lengths of 0.372 ± 0.009 μm and 0.404 ± 0.007 μm to 0.410 ± 0.011 μm and 0.513 ± 0.032 μm, respectively, in experimental rats. The phrenic nucleus is therefore capable of morphological plasticity as early as 2 h after spinal cord hemisection and this plasticity coincides temporally with the physiological augmentation of crossed phrenic nerve activity at 2 h. The data further suggest that these morphological changes may be part of the substrate for the unmasking of ineffective synapses during the crossed phrenic phenomenon.     

Premotor Ramping of Thalamic Neuronal Activity Is Modulated by Nigral Inputs and Contributes to Control the Timing of Action Release

The ventromedial (VM)/ventro-anterior-lateral (VAL) motor thalamus is a key junction within the brain circuits sustaining normal and pathologic motor control functions and decision-making. In this area of thalamus, on one hand, the inhibitory nigro-thalamic pathway provides a main output from the basal ganglia, and, on the other hand, motor thalamo-cortical loops are involved in the maintenance of ramping preparatory activity before goal-directed movements. To better understand the nigral impact on thalamic activity, we recorded electrophysiological responses from VM/VAL neurons while male and female mice were performing a delayed right/left decision licking task. Analysis of correct (corr) and error trials revealed that thalamic ramping activity was stronger for premature licks (impulsive action) and weaker for trials with no licks [omission (omi)] compared with correct trials. Suppressing ramping activity through optogenetic activation of nigral terminals in the motor thalamus during the delay epoch of the task led to a reduced probability of impulsive action and an increased amount of omissions trials. We propose a parsimonious model explaining our data and conclude that a thalamic ramping mechanism contributes to the control of proper timing of action release and that inhibitory nigral inputs are sufficient to interrupt this mechanism and modulate the amount of motor impulsivity in this task.SIGNIFICANCE STATEMENT Coordinated neural activity in motor circuits is essential for correct movement preparation and execution, and even slight imbalances in neural processing can lead to failure in behavioral tasks or motor disorders. Here we focused on how failure to regulate the control of activity balance in the motor thalamus can be implicated in impulsive action release or omissions to act, through an activity ramping mechanism that is required for proper action release. Using optogenetic activation of inhibitory basal ganglia terminals in motor thalamus we show that basal ganglia input is well positioned to control this ramping activity and determine the timing of action initiation.     

Nitric Oxide Inhibits Neuronal Activity in the Supraoptic Nucleus of the Rat Hypothalamic Slices

The presence of abundant nitric oxide synthase (NOS) in magnocellular neurons of the rat hypothalamus suggests that nitric oxide (NO) may be involved in controlling the release of oxytocin and vasopressin. To test this possibility, we examined the effect of NO-related drugs on extracellular discharges of 124 supraoptic nucleus (SON) neurons from slices of rat hypothalamus in vitro. Twenty-three (43%) of 53 neurons were inhibited by sodium nitroprusside (SNP), a spontaneous releaser of NO, at 1–3 mM. This inhibition was prevented by preincubation of the slices with 1

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hemoglobin, an inactivator of NO (

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), whereas hemoglobin alone enhanced neuronal activity in seven (35%) of 20 neurons.

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-Arginine (1 mM), a precursor of NO, inhibited neuronal activity in five (36%) of 14 neurons, while

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-arginine (1 mM), the inactive counterpart of

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-arginine, was ineffective (

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). N-

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-nitro-

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-arginine methyl ester (

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-NAME, 10

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), an inhibitor of NOS, also enhanced neuronal activity in five (29%) of 17 neurons, while N-

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-nitro-

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-arginine methyl ester (DNAME, 10

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), the inactive enantiomer of

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-NAME, was without effect (

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). Together, our data show that NO exerts predominantly an inhibitory effect on SON neurons and may serve as a negative feedback loop in controlling release of oxytocin and vasopressin.     

Increased Expression of the Growth-associated Protein GAP-43 in the Myelin-free Rat Spinal Cord

In the normal central nervous system (CNS) the regional expression of the growth-associated protein GAP43 is complementary to the pattern of myelination. This has led us to suspect that myelin-associated neurite growth inhibitors might contribute to the suppression of GAP-43 expression by suppressing sprouting and plastic changes of synaptic terminals in myelinated CNS areas. In order to study the relationship between myelination and GAP-43 expression more directly, we experimentally prevented myelination of the lumbar spinal cord of rats through neonatal X-irradiation. The GAP-43 protein expression in myelin-free spinal cords was analysed by immunohistochemistry and immunoblotting and compared to age-matched normal spinal cords. We found that in the absence of myelination, GAP-43 expression is strongly increased in the spinal cord of 4-week-old rats. GAP-43 was most strongly expressed in descending fibre tracts, where expression in the normal spinal cord is very low. In grey matter the typical regional pattern of GAP-43 expression did not develop; instead GAP-43 expression was high in all regions of the spinal cord. The overall pattern of myelination and GAP-43 expression in the myelin-free cord resembled that of early postnatal stages. This indicates that the regional down-regulation of GAP-43 expression during normal postnatal development did not occur in the myelin-free areas. Our results support the hypothesis that neurite growth inhibitors from oligodendrocytes and CNS myelin suppress sprouting and plastic changes of synaptic terminals in the normal CNS and are thereby involved in regulating the stability of neural connections.     

Inhibition of Neuronal Activity in the Nucleus of the Optic Tract due to Electrical Stimulation of the Medial Terminal Nucleus in the Rat

Morphologically, a GABAergic connection between the medial terminal nucleus of the accessory optic system and the nucleus of the optic tract, two primary visual nuclei involved in the optokinetic reflex, has been demonstrated. In this study it was investigated if the medial terminal nucleus forms an inhibitory input to movement direction selective units in the nucleus of the optic tract. Neurons in the nucleus of the optic tract were visually stimulated with moving large random square patterns in their preferred and non-preferred direction, and their activity was recorded extracellularly. Concomitantly, bipolar electrical stimulation was applied to the medial terminal nucleus and its effect was studied on the visual responses of units in the nucleus of the optic tract. Units in the nucleus of the optic tract were strongly inhibited during electrical stimulation of the medial terminal nucleus. The role of GABA in mediating this inhibition was investigated by applying bicuculline, a GABA_A receptor antagonist, iontophoretically to the recorded units in the nucleus of the optic tract. However, although average spike rate levels of units in the nucleus of the optic tract increased with bicuculline, bicuculline did not reduce inhibition invoked by electrical stimulation of the medial terminal nucleus. A possible explanation for this observation is that this inhibition is GABA_B receptor mediated.     

Ultrastructure and Distribution of Corticothalamic Fiber Terminals From the Posterior Cingulate Cortex and the Presubiculum to the Anteroventral Thalamic Nucleus of the Rat

The ultrastructure of axon terminals in the anteroventral thalamic nucleus arising in the cingulate cortex and in the presubiculum was examined using the anterograde transport of wheat germ agglutinin conjugated to horseradish peroxidase in rats. Anterogradely labeled axonal arborizations arising from the posterior cingulate cortex were concentrated bilaterally in the ventral part of the anteroventral nucleus. In electron micrographs these thalamic terminals arising from the posterior cingulate cortex were consistently small, contained round vesicles, and established asymmetric contacts on distal dendritic processes. In contrast, the axonal arborizations arising from the presubiculum were concentrated ipsilaterally in the dorsal part of the anteroventral nucleus and comprised two identifiable populations of terminals. The smaller terminals, which contained densely packed round vesicles, established asymmetric synaptic contacts on distal dendritic processes and resembled the posterior cingulate cortex terminals described above. The other population of the presubiculum terminals consisted of medium-sized terminals. These contained loosely packed round vesicles and established asymmetric synaptic contacts on proximal dendritic processes. These results indicate that the posterior cingulate cortex and the presubiculum project differentially upon the anteroventral thalamic nucleus. They also indicate that although the posterior cingulate cortex gives rise to only one type of corticothalamic terminal, the presubiculum gives rise to two types of corticothalamic terminals. When taken together, these data suggest that these different limbic cortical areas might subserve distinct roles in the anteroventral thalamic nucleus function.     

Graded Histological and Locomotor Outcomes after Spinal Cord Contusion Using the NYU Weight-Drop Device versus Transection

Injury reproducibility is an important characteristic of experimental models of spinal cord injuries (SCI) because it limits the variability in locomotor and anatomical outcome measures. Recently, a more sensitive locomotor rating scale, the Basso, Beattie, and Bresnahan scale (BBB), was developed but had not been tested on rats with severe SCI complete transection. Rats had a 10-g rod dropped from heights of 6.25, 12.5, 25, and 50 mm onto the exposed cord at T10 using the NYU device. A subset of rats with 25 and 50 mm SCI had subsequent spinal cord transection (SCI + TX) and were compared to rats with transection only (TX) in order to ascertain the dependence of recovery on descending systems. After 7–9 weeks of locomotor testing, the percentage of white matter measured from myelin-stained cross sections through the lesion center was significantly different between all the groups with the exception of 12.5 vs 25 mm and 25 vs 50 mm groups. Locomotor recovery was greatest for the 6.25-mm group and least for the 50-mm group and was correlated positively to the amount of tissue sparing at the lesion center (p < 0.0001). BBB scale sensitivity was sufficient to discriminate significant locomotor differences between the most severe SCI (50 mm) and complete TX (p < 0.01). Transection following SCI resulted in a drop in locomotor scores and rats were unable to step or support weight with their hindlimbs (p < 0.01), suggesting that locomotor recovery depends on spared descending systems. The SCI + TX group had a significantly greater frequency of HL movements during open field testing than the TX group (p < 0.005). There was also a trend for the SCI + TX group to have higher locomotor scores than the TX group (p > 0.05). Thus, spared descending systems appear to modify segmental systems which produce greater behavioral improvements than isolated cord systems.     

The Ability of Human Schwann Cell Grafts to Promote Regeneration in the Transected Nude Rat Spinal Cord

Advances in the purification and expansion of Schwann cells (SCs) from adult human peripheral nerve, together with biomaterials development, have made the construction of unique grafts with defined properties possible. We have utilized PAN/PVC guidance channels to form solid human SC grafts which can be transplanted either with or without the channel. We studied the ability of grafts placed with and without channels to support regeneration and to influence functional recovery; characteristics of the graft and host/graft interface were also compared. The T9–T10 spinal cord of nude rats was resected and a graft was placed across the gap; methylprednisolone was delivered acutely to decrease secondary injury. Channels minimized the immigration of connective tissue into grafts but contributed to some necrotic tissue loss, especially in the distal spinal cord. Grafts without channels contained more myelinated axons (x= 2129 ± 785) vs (x = 1442 ± 514) and were larger in cross-sectional area (x = 1.53 ± 0.24 mm²) vs (x= 0.95 ± 0.86 mm²). The interfaces formed between the host spinal cord and the grafts placed without channels were highly interdigitated and resembled CNS–PNS transition zones; chondroitin sulfate proteoglycans was deposited there. Whereas several neuronal populations including propriospinal, sensory, motoneuronal, and brainstem neurons regenerated into human SC grafts, only propriospinal and sensory neurons were observed to reenter the host spinal cord. Using combinations of anterograde and retrograde tracers, we observed regeneration of propriospinal neurons up to 2.6 mm beyond grafts. We estimate that 1% of the fibers that enter grafts reenter the host spinal cord by 45 days after grafting. Following retrograde tracing from the distal spinal cord, more labeled neurons were unexpectedly found in the region of the dextran amine anterograde tracer injection site where a marked inflammatory reaction had occurred. Animals with bridging grafts obtained modestly higher scores during open field [(x = 8.2 ± 0.35) vs (x = 6.8 ± 0.42),P = 0.02] and inclined plane testing (x = 38.6 ± 0.542) vs (x= 36.3 ± 0.53),P = 0.006] than animals with similar grafts in distally capped channels. In summary, this study showed that in the nude rat given methylprednisolone in combination with human SC grafts, some regenerative growth occurred beyond the graft and a modest improvement in function was observed.     

Secondary Cell Death and the Inflammatory Reaction After Dorsal Hemisection of the Rat Spinal Cord

Local spinal cord lesions are often greatly enlarged by secondary damage, a process which leads to massive additional cell death. This process is poorly understood. In order to investigate which types of cells could play a role in increasing the size of the lesion, we have analysed the events occurring at rat spinal cord lesion sites from 1 h to 3 months after partial transection using cell type-specific markers. One hour after transection, the lesion site was small and corresponded to the zone of primary mechanical damage. Extravasation of blood and an opening of the blood – brain barrier occurred. Rapidly thereafter, at 3 and 6 h, an area of secondary cell death developed around the zone of the primary lesion. This secondary cell death, which was probably largely of the necrotic type, affected neurons, macroglia and microglial cells indiscriminately. It was virtually complete at 12 h. Recruitment of inflammatory cells followed a time course which lagged behind that of secondary cell death. Adhesion of neutrophils to the inside of blood vessels was observed at 3 h. They appeared in large numbers at 6 h at the site of the primary lesion, but not yet in the area of secondary cell death. They were numerous throughout the lesion site at 24 h and then disappeared rapidly. Proliferation and recruitment of macrophages and microglial cells became predominant 2 days after injury. Their density was highest within the lesion site between 4 and 8 days. Very few astrocytes were present in the lesion site during the first week. In contrast, the surrounding area contained numerous activated astrocytes, which began to delineate the lesion site. After 2 weeks, the microglial cells and macrophages progressively disappeared from the lesion site, and a cavity formed. A glial scar surrounded this cavity and consisted of reactive astrocytes and activated microglial cells. The time course of the cellular reactions observed here suggests that secondary damage is not primarily due to destructive effects of neutrophils and macrophages. The inflammatory process after spinal cord transection is qualitatively similar to that observed outside the CNS. Inflammatory cells, which can release cytokines and growth factors, could play important roles in protective reactions of the tissue and glial scar formation.     

Poly I∶C与R848诱导大鼠脊髓细胞增殖的研究

目的 研究Poly I∶C与 R848对脊髓细胞增殖的诱导效应.方法 大鼠单次腹腔注射(ip)Poly I∶C与R848,增殖的细胞由BrdU跟踪标记.结果 Poly I∶C与 R848可引起大鼠脊髓BrdU 细胞明显增加,于注射后2～3 d达最高,随后快速降至正常水平,同时可见BrdU /Nestin 细胞存在,并伴小胶质细胞的活化,未见有ED-1 /BrdU 的细胞.地塞米松可抑制细胞增殖及小胶质细胞活化,而消炎痛无此作用.结论 配体被TLR识别后可能参与脊髓内正常神经细胞的发生过程,提示炎性及再生修复过程的紧密相关,这对开发促进组织再生修复的药物有一定价值.     

Regional Spinal Cord and Brain Blood Flows in the Rat

Regional spinal cord blood flow and blood flow in different brain areas were measured in 18 rats by the microsphere technique. By the use of spheres labeled with two different isotopes injected 5 min apart, double determinations were made. The consistency of the results from the two injections was very good. Blood flow was highest in the lumbar part of the spinal cord, somewhat lower in the lower thoracic part, lowest in the upper thoracic part, and again higher in the cervical cord; the mean values of the two determinations were 0.98, 0.74, 0.42, and 0.48 ml · min^-1 · g^-1 tissue for these regions, respectively. The brain areas investigated were the brain stem, cerebellum, and right and left hemispheres; the respective mean values of the two blood flow determinations in these areas were 0.54, 0.58, 0.33, and 0.38 ml · min^-1 · g^-1 tissue.     

Effect of CB1 Receptor Blockade on Food-Reinforced Responding and Associated Nucleus Accumbens Neuronal Activity in Rats

Studies have shown that disruption of cannabinoid receptor signaling reduces operant responses for rewards; yet it is unknown whether changes in neural activity at dopamine terminal regions such as the nucleus accumbens (NAc) underlie these behavioral effects. To study the neural correlates that accompany the disruption of endogenous cannabinoid (eCB) signaling in a food-motivated task, we recorded the neural activity and local field potentials (LFPs) from the NAc. A within-subject design was used for recordings as rats engaged in lever-pressing behavior for sucrose chocolate-flavored pellets delivered during responding in a progressive ratio (PR) schedule of reinforcement. Rats were food restricted to 85 ± 5% of their free body weight and trained under a PR until a stable breakpoint was observed (12 sessions ± 3). Once performance was stable, recordings were made under baseline, vehicle, and following administration of the cannabinoid inverse agonist rimonabant (150 μg/kg, i.v). NAc neurons encoded reward-predictive cues as well as food reward delivery. Rimonabant administration robustly reduced breakpoints in all rats tested, as previously reported. We found that this reduction is accompanied by a profound attenuation in the strength and coordination of specific event-related spiking activity. Moreover, rimonabant decreased LFP gamma power at 80 Hz (high gamma) at reward delivery and gamma power at 50 Hz (low gamma) at cue onset. Together the present results indicate that the eCB system sculpts neural activity patterns that accompany PR performance and reward consumption.     

Evaluation of the Combination of Methylprednisolone and Tranilast after Spinal Cord Injury in Rat Models

ObjectiveThe aim of our study was to evaluate the neuroprotective functions of the combination therapy using methylprednisolone (MP) and tranilast (TR) after spinal cord injury (SCI) in adult rats.MethodsSpinal cord compression injury model was achieved using Yasargil aneurysm clip. Rats were divided into control group, MP group, TR group, and combination therapy group using TR and MP. Rat models were assessed for locomotor functional recovery using Basso, Beattie, and Bresnahan (BBB) score, spinal cord water content and myeloperoxidase (MPO) activity 24 hours post SCI, haematoxylin and eosin staining and glial fibrillary acid protein (GFAP) staining at 7 and 14 days post SCI.ResultsThe spinal cord water content and MPO activity in the combination therapy group was significantly lower than the control group and the individual therapy groups p<0.05. The combination therapy group had significantly higher BBB scores than control group and individual therapy groups (p<0.05). At one week after SCI, GFAP expression in the combination group was significantly lower than the control group (p<0.05) but there was no significant difference compared to the individual therapy groups (p>0.05). At 2 weeks after SCI there was a slight decrease in GFAP expression compared to the first week but the difference was not statistically significant (p>0.05), GFAP expression between the groups was not statistically significant p>0.05.ConclusionCombining MP and TR is therapeutically more effective in improving functional recovery, inhibiting inflammation and glial scar formation after acute SCI.