Pattern of Glial Fibrillary Acidic Protein Expression Following Kainate-Induced Cerebellar Lesion in Rats

In the present study glial fibrillary acidic protein (GFAP) expression was assessed following intravermian injection of kainic acid (KA) or physiological saline to adult rat cerebellum. After 2- to 30-day recovery period, free-floating sections cut with a microtome were obtained and were proccessed for immunocytochemistry against GFAP. Injection of both kainate and physiological saline elicited significant astrogliotic reaction, i.e. in the area around the lesion thick GFAP-positive Bergmann fibers with typical orientation appeared in the molecular and hypertrophied astrocytes abundantly appeared in the granular layer. However, following kainate intoxication lesion was not surrounded by typical demarcation glial scar during 30-day recovery period in contrast to the appearance of usual glial scar in the group injected with physiological saline, as early as 7-day postlesion. Preserved spatial organization of Bergmann fibers and the absence of typical demarcating glial scar after kainate-induced cerebellar lesion suggest distinct pattern of astrogliosis that presents an interesting model system to study the importance of glial scar in the recovery after ischemic brain insults.     

Levetiracetam protects against kainic acid-induced toxicity

We investigated the Levetiracetam (LVT) ability to protect the brain against kainic acid (KA) induced neurotoxicity. Brain injury was induced by intraperitoneal administration of KA (10 mg/kg). Sham brain injury rats were used as controls. Animals were randomized to receive either LVT (50 mg/kg) or its vehicle (1 ml/kg) 30 min. before KA administration. Animals were sacrificed 6 hours after KA injection to measure brain malonildialdehyde (MDA), glutathione levels (GSH) and the mRNA for interleukin-1beta (IL-1beta) in the cortex and in the diencephalon. Behavioral changes were also monitored. Intraperitoneal administration of LVT decreased significantly MDA in the cortex (KA + vehicle = 0.25 +/- 0.03 nmol/mg protein; KA + LVT = 0.13 +/- 0.01 nmol/mg protein; P < 0.005), and in the diencephalons (KA + vehicle = 1,01 +/- 0.2 nmol/mg protein; KA + LVT = 0,33 +/- 0,08 nmol/mg protein; P < 0.005), prevented the brain loss of GSH in both cortex (KA + vehicle = 5 +/- 1 micromol/g protein; KA + LVT = 15 +/- 2 micromol/g protein; P < 0.005) and diencephalons (KA + vehicle = 9 +/- 0.8 micromol/g protein; KA + LVT = 13 +/- 0.3 micromol/g protein; P < 0.05), reduced brain IL-1beta mRNA and markedly controlled seizures. Histological analysis showed a reduction of cell damage in LVT treated samples. The present data indicate that LVT displays neuro-protective effects against KA induced brain toxicity and suggest that these effects are mediated, at least in part, by inhibition of lipid peroxidation.     

Dietary Restriction Enhances Kainate-Induced Increase in NCAM While Blocking the Glial Activation in Adult Rat Brain

In the present study effect of dietary restriction (DR) on neuronal plasticity markers neural cell adhesion molecule (NCAM) and its polysialylated form PSA-NCAM and astrocytic marker glial fibrillary acidic protein (GFAP) was assessed following brain injury by intraperitoneal injection of kainic acid or physiological saline in adult male wistar rats. After 7-day recovery period, rats were sacrificed to study the NCAM-ir, PSA-NCAM-ir, and GFAP-ir in all the groups with immunohistofluorescence and immunoblotting. We noticed increase in NCAM and PSA-NCAM expression after KA excitotoxicity, and DR enhanced this increase in NCAM and PSA-NCAM expression. A marked increase in NCAM and PSA-NCAM-ir was observed in CA3 region of hippocampus, subgranular region and hilus of dentate gyrus, hypothalamus, and piriform cortex in both vehicle treated as well KA-treated DR rats as compared to vehicle and KA-treated AL rats, respectively. Whenever, CNS is damaged it undergoes an injury response called reactive gliosis. Our study confirmed the neuroprotective role of DR as evident from attenuation of GFAP-ir and enhanced levels of neuronal plasticity markers NCAM and PSA-NCAM. The potential beneficial role of DR regimen in attenuating KA-induced reactive astrogliosis and enhancing expression of neuronal plasticity markers may point the way to new strategies of intervention therapy by DR that will facilitate recovery from ageing and disease related neuronal dysfunction and enhance restorative processes by modulating astrogliosis.     

The effect of melatonin on lipid peroxidation and nitrite/nitrate levels, and on superoxide dismutase and catalase activities in kainic acid-induced injury

Kainic acid (KA) initiates neuronal injury and death by inducing oxidative stress and nitric oxide release from various regions of the brain. It was recently shown that melatonin has free radical-scavenging action and may protect against kainate-induced toxicity. In order to assess the possible supportive effect of melatonin treatment in KA-induced injury in the rat brain cortex, we determined malondialdehyde (MDA) levels as an index of lipid peroxidation, and assessed the activities of catalase (CAT) and superoxide dismutase (SOD) and the levels of nitrite/nitrate 35 male rats were divided into five groups, each receiving a different intraperitoneal treatment: saline solution (0.2 ml), kainic acid (15 mg/kg), melatonin (20 mg/kg), KA then melatonin (each as above, 15 min apart), or melatonin then KA (each as above, 30 min apart). Administration of KA caused an about five-fold increase in the catalase activity and an increase in the SOD activity in the cortex relative to the activities for the controls. Treatment with melatonin 15 min after KA injection kept malondialdehyde levels and catalase and superoxide dismutase activities at the normal levels, and led to an increase in the levels of nitrite/nitrate. Our data suggests that melatonin treatment following KA administration has a protective effect on antioxidant enzyme activities and thus supports the role of melatonin and oxidative stress in the regulation of antioxidative enzyme activity.     

Age-Dependent Changes in Intrinsic Neuronal Excitability in Subiculum after Status Epilepticus

Kainic acid-induced status epilepticus (KA-SE) in mature rats results in the development of spontaneous recurrent seizures and a pattern of cell death resembling hippocampal sclerosis in patients with temporal lobe epilepsy. In contrast, KA-SE in young animals before postnatal day (P) 18 is less likely to cause cell death or epilepsy. To investigate whether changes in neuronal excitability occur in the subiculum after KA-SE, we examined the age-dependent effects of SE on the bursting neurons of subiculum, the major output region of the hippocampus. Patch-clamp recordings were used to monitor bursting in pyramidal neurons in the subiculum of rat hippocampal slices. Neurons were studied either one or 2-3 weeks following injection of KA or saline (control) in immature (P15) or more mature (P30) rats, which differ in their sensitivity to KA as well as the long-term sequelae of the KA-SE. A significantly greater proportion of subicular pyramidal neurons from P15 rats were strong-bursting neurons and showed increased frequency-dependent bursting compared to P30 animals. Frequency-dependent burst firing was enhanced in P30, but not in P15 rats following KA-SE. The enhancement of bursting induced by KA-SE in more mature rats suggests that the frequency-dependent limitation of repetitive burst firing, which normally occurs in the subiculum, is compromised following SE. These changes could facilitate the initiation of spontaneous recurrent seizures or their spread from the hippocampus to other parts of the brain.     

Choline acetyltransferase, glutamic acid decarboxylase and somatostatin in the kainic acid model for chronic temporal lobe epilepsy

The aim of the study was to investigate neurochemical changes in a kainic acid (KA; 10 mg/kg, s.c.)-induced spontaneous recurrent seizure model of epilepsy, 6 months after the initial KA-induced seizures. The neuronal markers of cholinergic and gamma-aminobutyric acid (GABA)ergic systems, i.e. choline acetyltransferase (ChAT) and glutamic acid decarboxylase (GAD) activities, and a marker for neuropeptide, i.e. level of somatostatin, have been investigated. The brain regions investigated were the hippocampus, amygdala/piriform cortex, caudate nucleus, substantia nigra and the frontal, parietal, temporal and occipital cortices. Six months after KA injection, reduced ChAT activity was observed in the amygdala/piriform cortex (47% of control; p<0.001), increased ChAT activity in the hippocampus (119% of control; p<0.01) and normal ChAT activity in the other brain regions. The activity of GAD was significantly increased in all analysed cortical regions (between 146 and 171% of control), in the caudate nucleus (144% of control; p<0.01) and in the substantia nigra (126% of control; p<0.01), whereas in the amygdala/piriform cortex, the GAD activity was moderately lowered. The somatostatin level was significantly increased in all cortical regions (between 162 and 221% of control) as well as in the hippocampus (119% of control), but reduced in the amygdala/piriform cortex (45% of control; p<0.01). Six months after KA injection, the somatostatin:GAD ratio was lowered in the amygdala/piriform cortex (49% of control) and in the caudate nucleus (41% of control), whereas it was normal in the hippocampus and moderately increased in the cortical brain regions. A positive correlation was found between seizure severity and the reduction of both ChAT activities and somatostatin levels in the amygdala/piriform cortex. The results show a specific pattern of changes for cholinergic, GABAergic and somatostatinergic activities in the chronic KA model for epilepsy. The revealed data suggest a functional role for them in the new network that follows spontaneous repetitive seizures.     

Biochemical consequences of kainic acid injection into the lateral brain ventricle in rat

Effects of a single intraventricular injection of kainic acid (KA) in a dose of 0.1 microgram per rat on the activity of different brain neurotransmitter systems were investigated. A decreased level of norepinephrine at 3 and 24 h and acceleration of its utilization at 3 h after application of KA were observed. These changes were also accompanied by a decreased level of dopamine at 24 h, increased utilization of dopamine at 3 h, increased levels of 5-hydroxytryptamine and 5-hydroxyindoleacetic acid at 3 and 24 h, as well as by shortened time of the turnover of 5-hydroxytryptamine. No disturbances in the function of the aminergic systems were noted at 120 h after injection of KA. Lowered activity of glutamic acid decarboxylase in the striatum, hippocampus, hypothalamus and cerebellum was observed at 24 h after administration of KA. At 480 h following application of KA, this lowering persisted in the hippocampus only. The most prominent changes in the level of gamma-aminobutyric were observed at 120 h in the striatum, hippocampus and cerebellum. A decreased level of gamma-aminobutyric acid was found in the striatum and cerebellum at 480 h following injection of KA. The observed changes in the dynamic equilibrium between various neurotransmitter systems may be a consequence of the direct or indirect influence of KA.     

Dynamic regulation of fibroblast growth factor 2 (FGF-2) gene expression in the rat brain following single and repeated cocaine administration

Administration of drugs of abuse can produce long-lasting effects on brain function, which involve modifications at neurotransmitter level as well as changes in proteins important for structural alterations of selected brain regions. The contribution of trophic factors in these events has so far been underestimated. Here, we demonstrate that a single cocaine injection selectively up-regulated fibroblast growth factor 2 (FGF-2) mRNA levels in the striatum and prefrontal cortex within 2 h, an effect that vanished by 24 h. However, prolonged exposure (5 or 14 days) to cocaine treatment produced an enduring elevation of FGF-2 mRNA levels that was evident 72 h after the last injection in the prefrontal cortex and could even persist for 14 days in the striatum, raising the possibility that cocaine treatment primes the brain, resulting in longer-lasting FGF-2 up-regulation in regions that are highly innervated by dopaminergic projections. The expression of FGF-2 was also significantly increased in the midbrain following acute or 5-day injection, suggesting that modulation of FGF-2 biosynthesis in dopamine-producing cells occurs only during early stages of cocaine exposure. Our results point to important mechanistic conclusions as to how cocaine alters FGF-2 expression. Whereas cocaine-induced changes in FGF-2 gene expression following a single injection could be ascribed to increased release of transmitters (mainly dopamine), enhanced FGF-2 gene expression following repeated administration identifies the trophic factor as part of the adaptive changes set in motion by cocaine.     

Downregulation of 14-3-3 Proteins in a Kainic Acid-Induced Neurotoxicity Model

The 14-3-3 proteins are among the most abundant proteins expressed in the brain, comprising about 1% of the total amount of soluble brain proteins. Through phosphoserine- and phosphothreonine-binding motifs, 14-3-3 proteins regulate many signaling proteins and cellular processes including cell death. In the present study, we utilized a well-known kainic acid (KA)-induced excitotoxicity rat model and examined the expression of 14-3-3 and its isoforms in the frontal cortex of KA-treated and control animals. Among the different 14-3-3 isoforms, abundant levels of eta and tau were detected in the frontal cortex, followed by sigma, epsilon, and gamma, while the expression levels of alpha/beta and zeta/delta isoforms were low. Compared to the control animals, KA treatment induced a significant downregulation of the overall 14-3-3 protein level as well as the levels of the abundant isoforms eta, tau, epsilon, and gamma. We also investigated two 14-3-3-interacting proteins that are involved in the cell death process: Bcl-2-associated X (BAX) and extracellular signal-regulated kinase (ERK). Both BAX and phosphorylated ERK showed increased levels following KA treatment. Together, these findings demonstrate an abundance of several 14-3-3 isoforms in the frontal cortex and that KA treatment can cause a downregulation of 14-3-3 expression and an upregulation of 14-3-3-interacting proteins BAX and phospho-ERK. Thus, downregulation of 14-3-3 proteins could be one of the early molecular events associated with excitotoxicity. This could lead to subsequent upregulation of 14-3-3-binding proteins such as BAX and phospho-ERK that contribute to further downstream apoptosis processes, eventually leading to cell death. Maintaining sufficient levels of 14-3-3 expression and function may become a target of therapeutic intervention for excitotoxicity-induced neurodegeneration.     

Formation of the base modification 8-hydroxyl-2'-deoxyguanosine and DNA fragmentation following seizures induced by systemic kainic acid in the rat

The formation of oxidative DNA damage as a consequence of seizures remains little explored. We therefore investigated the regional and temporal profile of 8-hydroxyl-2'-deoxyguanosine (8-OHdG) formation, a hallmark of oxidative DNA damage and DNA fragmentation in rat brain following seizures induced by systemic kainic acid (KA). Formation of 8-OHdG was determined via HPLC with electrochemical detection, and single- and double-stranded DNA breaks were detected using in situ DNA polymerase I-mediated biotin-dATP nick-translation (PANT) and terminal deoxynucleotidyl-transferase-mediated nick end-labeling (TUNEL), respectively. Systemic KA (11 mg/kg) significantly increased levels of 8-OHdG within the thalamus after 2 h, within the amygdala/piriform cortex after 4 h, and within the hippocampus after 8 h. Levels remained elevated up to sevenfold within these areas for 72 h. Smaller increases in 8-OHdG levels were also detected within the parietal cortex and striatum. PANT-positive cells were detected within the thalamus, amygdala/piriform cortex, and hippocampus 24-72 h following KA injection. TUNEL-positive cells appeared within the same brain regions and over a similar time course (24-72 h) but were generally lower in number. The present data suggest oxidative damage to DNA may be an early consequence of epileptic seizures and a possible initiation event in the progression of seizure-induced injury to DNA fragmentation and cell death.     

Dantrolene protects neurons against kainic acid induced apoptosis in vitro and in vivo

Apoptotic cell death induced by kainic acid (KA) in cultures of rat cerebellar granule cells (CGC) and in different brain regions of Wistar rat pups on postnatal day 21 (P21) was studied. In vitro , KA (100–500 μM) induced a concentration-dependent loss of cell viability in MTT assay and cell death had apoptotic morphology as studied by chromatin staining with propidium iodide (PI). In vivo , twenty-four hours after induction of status epilepticus (SE) by an intraperitoneal KA injection (5 mg/kg) we quantified apoptotic cells in hippocampus (CA1 and CA3), parietal cortex and cerebellum using PI staining and terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) technique. We report that dantrolene, a specific ryanodine receptor antagonist, was able to significantly reduce the apoptotic cell death in CGC cultures and in hyppocampal CA1 and parietal cortex regions. Our finding can be valuable for neuroprotective therapy strategies in patients with repeated generalized seizures or status epilepticus.     

Enhanced Brain Cell Proliferation Following Early Adrenalectomy in Rats

We have previously demonstrated an increase in adult brain DNA content in rats adrenalectomized on postnatal day 11. The present studies examined cell proliferation in cerebral cortex, cerebellum, hippocampus, and midbrain-diencephalon following adrenalectomy at this age. Compared to sham-operated controls, adrenalectomized animals showed increased [3H]thymidine incorporation into DNA (measured at 1 h following a pulse injection) in all brain regions at 7 and 14 days postsurgery. In some areas, the effect was already present as early as 2 days following adrenalectomy. Chronic replacement with corticosterone prevented this increase in DNA labelling in a dose-dependent manner. When cell proliferation in the cerebral cortex and cerebellum was independently assessed by measuring changes in thymidine kinase activity, enzyme activity was significantly elevated in both areas at 7 and 14 days postsurgery. Finally, histological examination of the cerebellar cortex suggested a delayed disappearance of the external granular layer in several cerebellar lobules of adrenalectomized animals. Overall, these findings indicate that day-11 adrenalectomy leads to a prolonged stimulation of mitotic activity in areas where cell formation at this time is exclusively glial (i.e., cerebral cortex and mid-brain-diencephalon) as well as in areas where postnatal neurogenesis is also occurring (cerebellum and hippocampus). It is hypothesized that this stimulation results from the removal of a tonic inhibitory effect exerted by circulating glucocorticoids in the normal intact animal.     

Effects of unilateral lesion of the inferior olive on L-[3H] aspartate receptors binding in synaptic membranes of cat cerebellar cortex

In adult cats, local injection of kainic acid (KA) in the inferior olive (IO) of one side, from which the crossed olivocerebellar projection originates, produced asymmetric postural and motor deficits, attributed to selective damage of the olivary neurons. Since aspartate is one of the putative transmitters of the olivocerebellar fibers, experiments were performed to find out whether 6-8 days after injection of KA within the IO of one side produced changes in aspartate receptors binding in different zones of the cerebellar cortex. In particular, binding in the contralateral zones of the cerebellar cortex was referred to proteins contained in membrane suspensions and compared with the control values obtained in the same experiments from the ipsilateral zones. Binding of L-[3H] aspartate decreased on the average to 53.4% of the control value in the medial zone and to 86.1% of the control value in the intermediate and lateral zones of the cerebellar cortex. This reduction varied in different experiments according to the side of the injection, in agreement with the well known pattern of regional distribution of the olivocerebellar projection within the cerebellar cortex. These findings favour aspartate as the putative neurotransmitter of the climbing fibers. The demonstration that binding of aspartate decreased in the cerebellar cortex of one side, 6-8 days after injection of KA in the corresponding IO, indicates that plastic events occur at this level following destruction of the olivocerebellar pathway. In particular, the reduced binding can be attributed either to a decrease in number of the postsynaptic receptor sites for aspartate or to a decreased affinity of this amino acid for the corresponding receptors. These findings, however, do not exclude that an hypersensitivity by denervation may occur at the level of individual Purkinje cells when they are deprived of the climbing fibers input. In order to answer this question further experiments are required to find out how the binding for aspartate is modified at increasing time intervals after the olivary lesion.     

一次给予红藻氨酸对大鼠脑内细胞信息传递通路及癫痫敏感性的作用

本实验给大鼠皮下注射红藻氨酸（ＫＡ,１０ｍｇ／ｋｇ）诱发癫痫活动,７２ｄ后进行深部前梨状皮层（ｄｅｅｐ ｐｒｅｐｙｒｉｆｏｒｍ ｃｏｒｔｅｘ,ＤＰＣ）电点燃刺激（ｋｉｎｄｌｉｎｇ）,该组动物点燃形成加速,或再给予同样剂量ＫＡ,其再次诱发的癫痫活动明显加重。ｃ－Ｆｏｓ免疫反应活性（ｃ－Ｆｏｓ－ｉｒ）作为神经元兴奋的标志,标绘再次诱发癫痫活动时大鼠脑内细胞信息传递通路,并与对照组,即７２ｄ前给予生理盐     

Kainic acid—induced excitotoxicity is associated with a complex c-Fos and c-Jun response which does not preclude either cell death or survival

c-fos and c-jun mRNA induction and c-Fos and c-Jun protein expression were examined in the brains of adult rats subjected to systemic kainic acid (KA) injection at convulsant doses. Induction of c-fos and c-jun mRNA, as seen with in situ hybridization, occurred in the piriform and entorhinal cortices, neocortex, amygdala, hippocampus, dentate gyrus, and discrete thalamic nuclei. This was followed by c-Fos protein expression, as revealed with immunohistochemistry, in the same regions. However, the distribution of c-Jun protein expression differed depending on the antibody used. The distribution of cells immunostained with the antibody c-Jun (AB-1) was similar to that of c-jun mRNA, but the distribution of cells immunostained with the antibody c-Jun/AP1 (N) was restricted to a few neurons in the pyramidal cell layer of CA1 and CA3, layer II of the piriform and entorhinal cortices, basal amygdala, and discrete thalamic nuclei. Although the regional distribution of c-Fos- and c-Jun-immunoreactive cells in the hippocampus, layer II of the entorhinal and piriform cortices, basal amygdala, and discrete thalamic nuclei matched the distribution of cells committed to dying, c-Fos- and c-Jun-immunoreactive cells in the neocortex and dentate gyrus survived. Therefore, the present data show that c-fos and c-jun are not predictors of either cell death or survival, but rather, markers of cells sensitive to KA excitotoxicity. Western blots to c-Fos showed a double band at p62 in samples containing the hippocampus and entorhinal and piriform cortices (hip samples) and in samples containing the neocortex (cortex samples). The upper band was abolished following preincubation of the samples with alkaline phosphatase, thus suggesting c-Fos phosphorylation. Western blots to c-Jun (AB-1) showed a single band at about p39 in hip and cortex. However, Western blots to c-Jun/AP1 (N) identified two bands. One band at about p39 was seen in control rats and the cortex of KA-treated rats. Another band at p26 was observed only in hip samples of KA-treated rats. In addition, decreased c-Jun N-terminal kinase 1 (JNK-1) expression, as revealed on Western blots, was coincidental with the appearance of the p26 c-Jun-immunoreactive band in KA-treated rats. These results show that c-Fos and different Jun-related antigens are expressed following KA excitotoxicity, and that posttranslational modifications involving phosphorylation of c-Fos and Jun(s) may occur following KA injection. These results also stress the necessity of examining the composition of Fos and Jun-related antigens and the metabolic state of Fos and Jun(s) in different experimental models of nervous system injury. © 1997 John Wiley & Sons, Inc. J Neurobiol 33: 232–246, 1997     

Differential regulation of ciliary neurotrophic factor and its receptor in the rat hippocampus in response to kainic acid-induced excitotoxicity

We analyzed the changes in expression of ciliary neurotrophic factor (CNTF) and its receptor, ligand-binding subunit a (CNTFRa), in the hippocampus following intraperitoneal administration of a convulsant dose of kainic acid (KA). Immunohistochemistry and immunoblotting showed that CNTF levels rose dramatically between day 1 and day 10, and that the CNTF was located in reactive astrocytes. In contrast, upregulation of CNTFRalpha mRNA, occurred in neurons as well as astrocytes. A rapid, and short-lived (3 h-2 d) increase in CNTFRalpha was also observed in the more resistant granule cells and CA2 pyramidal neurons. The increase in astrocytes was detected by day 1 and was sustained for more than 5 d. These results show that CNTF and CNTFRalpha are differentially regulated in hippocampal neurons and reactive astrocytes following KA injection, indicating that these proteins may be involved in the regulation of astrocyte and neuronal degenerative responses.     

Gene expression profiling of individual cases reveals consistent transcriptional changes in alcoholic human brain

Chronic alcohol exposure induces lasting behavioral changes, tolerance, and dependence. This results, at least partially, from neural adaptations at a cellular level. Previous genome-wide gene expression studies using pooled human brain samples showed that alcohol abuse causes widespread changes in the pattern of gene expression in the frontal and motor cortices of human brain. Because these studies used pooled samples, they could not determine variability between different individuals. In the present study, we profiled gene expression levels of 14 postmortem human brains (seven controls and seven alcoholic cases) using cDNA microarrays (46,448 clones per array). Both frontal cortex and motor cortex brain regions were studied. The list of genes differentially expressed confirms and extends previous studies of alcohol responsive genes. Genes identified as differentially expressed in two brain regions fell generally into similar functional groups, including metabolism, immune response, cell survival, cell communication, signal transduction and energy production. Importantly, hierarchical clustering of differentially expressed genes accurately distinguished between control and alcoholic cases, particularly in the frontal cortex.     

Expression and localisation of brain-type organic cation transporter (BOCT/24p3R/LCN2R) in the normal rat hippocampus and after kainate-induced excitotoxicity

The iron siderophore binding protein lipocalin 2 (LCN2, also known as 24p3, NGAL and siderocalin) may be involved in iron homeostasis, but to date, little is known about expression of its putative receptor, brain-type organic cation transporter (BOCT, also known as BOCT1, 24p3R, NGALR and LCN2R), in the brain during neurodegeneration. The present study was carried out to elucidate the expression of LCN2 and BOCT in hippocampus after excitotoxicity induced by the glutamate analog, kainate (KA) and a possible role of LCN2 in neuronal injury. As reported previously, a rapid and sustained induction in expression of LCN2 was found in the hippocampus after intracerebroventicular injection of KA. BOCT was expressed in neurons of the saline-injected control hippocampus, and immunolabel for BOCT protein was preserved in pyramidal neurons of CA1 at 1 day post-KA injection, likely due to the delayed onset of neurodegeneration after KA injection. At 3 days and 2 weeks after KA injections, loss of immunolabel was observed due to degenerated neurons, although remaining neurons continued to express BOCT, and induction of BOCT was found in OX-42 positive microglia. This resulted in an overall decrease in BOCT mRNA and protein expression after KA treatment. Increased expression of the pro-apoptotic marker, Bim, was found in both neurons and microglia after KA injection, but TUNEL staining indicating apoptosis was found primarily in Bim-expressing neurons, but not microglia. Interaction between LCN2 and BOCT was found by DuoLink assay in cultured hippocampal neurons. Apo-LCN2 without iron caused no significant differences in neuronal Bim expression or cell survival, whereas holo-LCN2 consisting of LCN2:iron:enterochelin complex increased Bim mRNA expression and decreased neuronal survival. Together, results suggest that LCN2 and BOCT may have a role in neuronal injury.