Localization of L-type calcium channel CaV1.3 in cat lumbar spinal cord – with emphasis on motoneurons

Voltage-dependent persistent inward currents (PICs) which underlie the plateau potentials are an important intrinsic property of spinal motoneurons. Electrophysiological experiments have indicated that a subtype of the low threshold L-type calcium channel, Ca_V1.3, mediates this current. In mouse and turtle lumbar spinal cord it has been shown that these channel proteins are mainly found on motoneuron dendrites. In the present study we have used immunohistochemistry to locate these channels in lumbar spinal neurons, especially motoneurons, of the cat. The results indicate that Ca_V1.3 immunoreactivity was unevenly distributed among the laminae of the spinal grey matter. The small neurons in superficial dorsal horn (laminae I–III) were sparsely and weakly labelled, while large neurons in ventral horn were frequently and densely labelled. Groups of motoneurons in lamina IX that were immunoreactive to choline acetyltransferase also co-expressed Ca_V1.3. The immmunoreactivity was mainly associated with neuronal somata and proximal dendrites. Double staining with antibodies against Ca_V1.3 and MAP2 (a dendritic marker) showed that some fine fibres, which may include distal dendrites, were also labelled. These results in the cat spinal cord show some differences from studies in mouse and turtle motoneurons where the immunoreactivity against this channel was mainly localized to the dendrites.     

Rapid regulation of microtubule-associated protein 2 in dendrites of nucleus laminaris of the chick following deprivation of afferent activity

Differential innervation of segregated dendritic domains in the chick nucleus laminaris (NL), composed of third-order auditory neurons, provides a unique model to study synaptic regulation of dendritic structure. Altering the synaptic input to one dendritic domain affects the structure and length of the manipulated dendrites while leaving the other set of unmanipulated dendrites largely unchanged. Little is known about the effects of neuronal input on the cytoskeletal structure of NL dendrites and whether changes in the cytoskeleton are responsible for dendritic remodeling following manipulations of synaptic input. In this study, we investigate changes in the immunoreactivity of high-molecular weight microtubule associated protein 2 (MAP2) in NL dendrites following two different manipulations of their afferent input. Unilateral cochlea removal eliminates excitatory synaptic input to the ventral dendrites of the contralateral NL and the dorsal dendrites of the ipsilateral NL. This manipulation produced a dramatic decrease in MAP2 immunoreactivity in the deafferented dendrites. This decrease was detected as early as 3 h following the surgery, well before any degeneration of afferent axons. A similar decrease in MAP2 immunoreactivity in deafferented NL dendrites was detected following a midline transection that silences the excitatory synaptic input to the ventral dendrites on both sides of the brain. These changes were most distinct in the caudal portion of the nucleus where individual deafferented dendritic branches contained less immunoreactivity than intact dendrites. Our results suggest that the cytoskeletal protein MAP2, which is distributed in dendrites, perikarya, and postsynaptic densities, may play a role in deafferentation-induced dendritic remodeling.     

Effect of excitatory amino acids on microtubule-associated proteins in cultured cortical and spinal neurones

The effect of excitatory amino acid stimulation on the cytoskeleton of cultured spinal cord and cortical neurons was monitored with antibodies against microtubule-associated proteins tau and MAP2. In unstimulated cultures tau-1 immunoreactivity was restricted to axon-like processes. Stimulation with glutamate (0.1-1 mM) or N-methyl-D-aspartate (NMDA) (0.1 mM) resulted in a dramatic increase in the intensity of tau labelling in axons and the appearance of staining within a proportion of neuronal cell bodies and dendrites. Quisqualate or kainate stimulation resulted only in an increase in tau immunoreactivity within axons. The NMDA mediated events were calcium dependent and the effects of all excitatory amino acids could be blocked by specific antagonists. In contrast, following stimulation with excitatory amino acids, MAP2-immunoreactivity was associated with filaments which formed a complex network within the cell body. This suggests that the different excitatory amino acid receptor subtypes can have differential effects on the neuronal cytoskeleton.     

Alz-50 recognizes epitopes in primary sensory fibres and in neurons of the substantia gelatinosa of the spinal cord. An ultrastructural study in the rat

Summary The monoclonal antibody Alz-50 has been proposed as a marker for cellular pathological changes in Alzheimer's disease. However, it has been reported that this antibody also reacts with specific epitopes in normal individuals. Furthermore, intense Alz-50 immunoreactivity has been recently described in the hypothalamus and spinal cord of rat and monkey. In the present study, we analysed the distribution pattern of Alz-50 immunostaining in the spinal cord of the adult rat. Using light microscopy, immunostained fibres and varicosities were detected mainly in laminae I-II, although some immunostaining could be detected in deeper laminae. At the ultrastructural level, immunostained axonal varicosities could be detected in lamina I and the outer two thirds of lamina II. The varicosities appeared either scalloped or dome-shaped and contained numerous agranular synaptic vesicles and a few dense-core vesicles. Most varicosities were presynaptic to dendrites. A few immunostained cell bodies and dendrites were also observed, but glial cells were never immunostained. Some ultrathin sections were processed for postembedding immunogold detection of calcitonin gene-related peptide and GABA immunoreactivities. Most of the varicosities which were immunoreactive for Alz-50 also showed calcitonin gene-related peptide immunoreactivity. In contrast, GABA immunoreactivity was never co-localized with Alz-50 immunoreactivity. These results indicate that, in the superficial dorsal horn, the epitope recognized by the Alz-50 antibody is located mainly, but not exclusively, in primary sensory fibres.     

The neuronal response to injury as visualized by immunostaining of class III beta-tubulin in the rat

The neuronal response to trauma of the brain and spinal cord was examined by staining sections of injured central nervous system (CNS) with a monoclonal antibody (TuJ1) that recognizes class III beta-tubulin exclusively. Because class III beta-tubulin is expressed by neurons and not by glia, this monoclonal antibody stains neuronal cell bodies, dendrites, axons and axonal terminations darkly with a pale staining background. Thus, the TuJ1 antibody is extremely useful, revealing the fine details of axons and their terminations, as well as significant injury-related alterations in the composition of the somatic cytoskeleton.     

Microtubule-associated protein 2 as a sensitive marker for cerebral ischemic damage--immunohistochemical investigation of dendritic damage

We investigated the neuronal distribution of microtubule-associated protein 2 in gerbil brain and monitored the progression of ischemic damage immunohistochemically by using this protein as a dendritic marker. The reaction for microtubule-associated protein 2 in normal gerbil brain clearly visualized neuronal soma and dendrites but other structures such as axonal bundles, glia and endothelial cells exhibited little immunoreactivity. In a reproducible gerbil model of unilateral cerebral ischemia, we could detect the ischemic lesions as early as 3 min after right common carotid occlusion at the subiculum-CA1 region of the ipsilateral hippocampus as faint loss of the reaction in the dendrites. After ischemia for 30 min, the ischemic lesions were clearly detected as loss of the reaction in the nerve cell bodies, dendrites and the neuropil in the hippocampus, cerebral cortex, thalamus and the caudoputamen. Although the mechanism for prompt disappearance of the immunohistochemical reaction for microtubule-associated protein 2 is not clear, the present investigation suggests that dendrites in the vulnerable regions may be quite susceptible to ischemic stress and that the immunohistochemical procedure for microtubule-associated protein 2 may be very useful for demonstration of dendritic damage in various pathophysiological states of the central nervous system.     

Monoclonal antibody BM89 recognizes a novel cell surface glycoprotein of the L2/HNK-1 family in the developing mammalian nervous system.

A monoclonal antibody, BM89, obtained with Triton X-114-treated pig synaptic membranes as an immunogen, recognizes a neuronal antigen in the newborn porcine nervous system. By immunohistochemistry, BM89 staining was observed within the neuropil of all areas of the forebrain and spinal cord tested. In addition, BM89 labeled the cell bodies and proximal dendrites of spinal cord neurons. In the peripheral nervous system, BM89 immunoreactivity was present in a subpopulation of dorsal root ganglion neurons and was predominantly associated with non-myelinated axons in peripheral nerves. Initial biochemical characterization of the antigen in pig brain showed that it is an integral membrane glycoprotein with a molecular weight of 41,000. Moreover, it cross-reacts with the L2/HNK-1 carbohydrate epitope expressed by members of a large family of glycoproteins. Homologous antigens with molecular weights of 41,000-43,000 were identified in the rat, rabbit and fetal human brain. Immunoblotting and immunohistochemistry revealed that the epitope recognized by BM89 is developmentally regulated in the rat nervous system. In cryostat sections from rat cerebellum, spinal cord and dorsal root ganglia, an age-dependent decline of BM89 immunoreactivity was observed during postnatal development. In the cerebellum, the BM89 epitope was very abundant in cells of the external and the internal granular layers between postnatal days 5 and 15. During this period some staining was also identified in the developing molecular layer and the prospective white matter. Subsequently, and in the adult, overall staining was greatly reduced and remaining immunoreactivity was associated only with the internal granular layer. In the spinal cord and dorsal root ganglia, staining was very prominent at postnatal day 5; it decreased considerably thereafter and was barely detectable in the adult. Immunostaining of rat brain and dorsal root ganglion cultures revealed that the BM89 antigen is a cell surface molecule expressed by a subpopulation of central and peripheral nervous system neurons. The biochemical properties in conjunction with the topographical location and the developmental profile of the antigen recognized by BM89 suggest that it may represent a developmentally important recognition molecule.     

小鼠臂丛离断对脊髓运动神经元树突结构与形态退变的影响

目的 研究臂丛离断后脊髓运动神经元树突退变与时间和损伤距离的相关性。 方法 在距离椎间孔3 mm或10 mm处处离断小鼠臂丛,术后7、14、28、56 d取材,采用MAP2免疫荧光染色和体视学分析、Golgi-Cox染色和Sholl分析观测颈膨大处脊髓前角运动神经元的树突结构和形态变化;术后28 d比较距离椎间孔3 mm和10 mm臂丛离断对脊髓运动神经元树突的影响。 结果 MAP2免疫荧光显示臂丛离断导致脊髓前角内树突的密度和完整性随时间延长逐渐下降;Golgi-Cox染色和Sholl分析显示运动神经元最长树突、总树突长度、树突最大跨度、树突3级分支的数量均呈时间依赖性下降。与距离椎间孔10 mm处离断组相比,3 mm处离断引起的树突长度退变更为明显。 结论 脊髓运动神经元树突在周围神经损伤后会发生退变,随时间延长其退变程度加重,随损伤部位与脊髓的距离延长树突长度退变程度减轻。     

Ultrastructural evidence for the occurrence of two distinct somatostatin-containing systems in the substantia gelatinosa of rat spinal cord

The light microscopic and ultrastructural distribution of somatostatin immunoreactivity has been studied in laminae I-III of the rat cervical spinal cord by means of a bi-specific anti-somatostatin/anti-horseradish peroxidase monoclonal antibody. Immunoreactivity was demonstrated in small rostro-caudally oriented nerve cells of ventral lamina II. Somatostatin-immunoreactive axonal varicosities contained round, agranular, synaptic vesicles and some large granular vesicles. These varicosities established either symmetric or asymmetric synaptic contacts with dendrites, presynaptic dendrites or cell bodies. In the middle third of lamina II, a small number of somatostatin-immunoreactive varicosities were the central elements of type I synaptic glomeruli. Immunoreactivity for somatostatin was also detected in dendritic profiles of laminae II-III. Some of these dendrites were part of synaptic glomeruli, and a small number of them were presynaptic dendrites. The latter were sometimes presynaptic to the central glomerular bouton. The results favor a participation of somatostatin-containing spinal interneurons in the modulation of sensory information.     

Immunohistochemical localization of glial cell line-derived neurotrophic factor in the human central nervous system

Glial cell line-derived neurotrophic factor, initially purified from the rat glial cell line B49, has the ability to promote the survival and differentiation of various types of neurons in the central and peripheral nervous systems. In the present study, to evaluate the physiological role of glial cell line-derived neurotrophic factor in the central nervous system, we investigated the cellular and regional distribution of glial cell line-derived neurotrophic factor immunoreactivity in autopsied control human brains and spinal cords using a polyclonal glial cell line-derived neurotrophic factor-specific antibody. On western blot analysis, the antibody reacted with recombinant human glial cell line-derived neurotrophic factor, and recognized a single band at a molecular weight of approximately 34,000 in human brain homogenates. Glial cell line-derived neurotrophic factor immunoreactivity was observed mainly in the neuronal somata, dendrites and axons. In the telencephalon, diencephalon and brainstem, the cell bodies and proximal processes of several neuronal subtypes were immunostained with punctate dots. Furthermore, immunopositive nerve fibers were also observed, and numerous axons were intensely immunolabeled in the internal segment of the globus pallidus and the pars reticulata of the substantia nigra. In the cerebellum, the most conspicuous immunostaining was found in the Purkinje cells, in which the somata and dendrites were strongly immunolabeled. Intense immunoreactivity was also detected in the posterior horn of the spinal cord. In addition to the neuronal elements, immunopositive glial cell bodies and processes were observed in various regions.

Our results suggest that glial cell line-derived neurotrophic factor is widely localized, but can be found selectively in certain neuronal subpopulations of the human central nervous system. Glial cell line-derived neurotrophic factor may regulate the maintenance of neuronal functions under normal circumstances.     

Ontogeny of microtubule-associated protein 2 in rat cerebellum: Differential expression of the doublet polypeptides

We have examined the ontogeny of the microtubule-associated protein, MAP2 in rat cerebellum using biochemical and immunocytochemical techniques. In adult animals MAP2 can be resolved as a doublet of polypeptides (referred to here as MAP2a and MAP2b). In young rats only the lower molecular weight MAP2b was present in cerebellar cytosol; MAP2a appeared by 20 days postnatally. The identification of the polypeptides as MAP2a and MAP2b in heat-stable fractions of cytosol was confirmed by peptide mapping which also demonstrated that MAP2a and MAP2b shared virtually identical peptide maps. Using a rabbit anti-MAP2 antibody that was characterised by immunoblotting of cerebellar homogenates, the localisation of MAP2 was examined in 10-day-old and adult cerebella. In 10-day-old animals, MAP2 immunoreactivity was detected in the external germinal layer, granular layer and most strikingly in Purkinje cell bodies and dendrites. Parallel fibre axons were unstained. In contrast both axons and dendrites were stained by an antibody against α-tubulin. In adult animals MAP2 immunoreactivity was largely confined to Purkinje cell dendrites.The absence of assembled microtubules from Purkinje cell dendrites of young animals despite the presence of MAP2 and tubulin immunoreactivity may be explained by the presence of only a single MAP2 polypeptide (MAP2b) whereas the presence of the MAP2 doublet polypeptides in the adult may facilitate polymerization. Since MAP2b does not co-assemble with microtubules efficiently in vitro it may represent a form of MAP2 unable to stimulate microtubule assembly. Therefore, the possibility exists that MAP2b may play an alternative role during dendritic growth.     

Permanent occlusion of the middle cerebral artery upregulates expression of cytokines and neuronal nitric oxide synthase in the spinal cord and urinary bladder in the adult rat

The expression pattern of proinflammatory cytokines, neuronal nitric oxide synthase (nNOS), substance P (SP) and calcitonin gene related peptide (CGRP) in the spinal cord and the bladder in response to permanent middle cerebral artery occlusion (MCAO) was investigated. In this connection, the gene expression of tumor necrosis factor alpha (TNF-alpha), interleukin-1 beta (IL-1beta) and interleukin-6 in the lumbosacral spinal cord and the bladder as determined by real-time polymerase chain reaction was upregulated. In the spinal cord, the immunoreactivity of TNF-alpha and IL-1beta was mainly localized in the ventral horn motoneurons contralateral to MCAO. In the bladder, TNF-alpha was mainly expressed in the inflammatory cells. The expression of nNOS immunoreactivity as well as nicotinamide adenine dinucleotide phosphate-diaphorase (NADPH-d) staining in the spinal cord and bladder was also markedly increased in response to MCAO. Furthermore, the temporal and spatial expression of nNOS paralleled that of TNF-alpha and IL-1beta in the spinal cord. On the other hand, there was no noticeable change in gene expression and immunoreactivity of SP and CGRP. The present results have shown that cytokines and nNOS expression are elevated in areas far removed from the primary site of ischemic infarct, namely, the lumbosacral spinal cord and bladder. This together with some neuronal deaths maybe linked to the dysfunction of the latter in a clinical stroke. On the other hand, the apparent lack of SP and CGRP changes following MCAO suggests that the two neurotransmitters are not directly involved.     

Immunolocalization of the arachidonic acid and mechanosensitive baseline TRAAK potassium channel in the nervous system

TRAAK is the sole member of the emerging class of 2P domain K⁺ channels to be exclusively expressed in neuronal cells. TRAAK produces baseline K⁺ currents which are strongly stimulated by arachidonic acid and by mechanical stretch, and which are insensitive to the classical K⁺ channel blockers tetraethylammonium, Ba²⁺, and Cs⁺. This report describes the immunolocalization of TRAAK in brain, spinal cord, and retina of the adult mouse. The most striking finding is the widespread distribution of the TRAAK immunoreactivity, with a prominent staining of the cerebellar cortex, neocortex, hippocampus, dentate gyrus, subiculum, the dorsal hippocampal commisure, thalamus, caudate–putamen, olfactory bulb, and several nuclei in the brainstem. Virtually all neurons express TRAAK, and the highest immunoreactivity was seen in soma, and to a lesser degree in axons and/or dendrites in most areas in brain and spinal cord. In the retina, the TRAAK protein is concentrated to the soma of ganglion cells and to the dendrites of all other neurons.Taken together, these results show a wide distribution of TRAAK, a mechanosensitive and arachidonic acid-stimulated neuron-specific baseline K⁺ channel, in brain, spinal cord and retina.     

Immunocytochemistry of B-50 (GAP-43) in the spinal cord and in dorsal root ganglia of the adult cat

Summary The distribution of the neural-specific growth associated protein B-50 (GAP-43), which persists in the mature spinal cord and dorsal root ganglia, has been studied by light and electron microscopic immunohistochemistry in the cat. Throughout the spinal cord, B-50 immunoreactivity was seen confined to the neuropil, whereas neuronal cell bodies were unreactive. The most conspicuous immunostaining was observed in the dorsal horn, where it gradually decreased from superficial laminae (I–II) toward more ventral laminae (III–V), and in the central portion of the intermediate gray (mainly lamina X). In these regions, the labelling was localized within unmyelinated, small diameter nerve fibres and axon terminals. In the rest of the intermediate zone (laminae VI–VIII), B-50 immunoreactivity was virtually absent. The intermediolateral nucleus in the thoracic and cranial lumbar cord showed a circumscribed intense B-50 immunoreactivity brought about by the labelling of many axon terminals on preganglionic sympathetic neurons. In motor nuclei of the ventral horn (lamina IX), low levels of B-50 immunoreactivity were present in a few axon terminals on dendritic and somal profiles of motoneurons. In dorsal root ganglia, B-50 immunoreactivity was mainly localized in the cell bodies of small and medium-sized sensory neurons. The selective distribution of persisting B-50 immunoreactivity in the mature cat throughout sensory, motor, and autonomie areas of the spinal cord and in dorsal root ganglia suggests that B-50-positive systems retain in adult life the capacity for structural and functional plasticity.     

The effects of quisqualate and nocodazole on the organization of MAP2 and neurofilaments in spinal cord neurons in vitro.

The relationship between microtubules, neurofilaments and microtubule-associated protein (MAP)2 was investigated in spinal cord neurons grown for up to 14 days in vitro. Neurons were labelled using antibodies against MAP2, neurofilaments and tubulin, and immunofluorescence analyzed by confocal microscopy. A well-structured network of neurofilaments and microtubules was observed in unstimulated cultures. MAP2 staining was poorly structured but became more filamentous following depolymerization of microtubules with nocodazole. Double-staining experiments suggested that MAP2 was now closely associated with neurofilaments in cell bodies and dendrites. Stimulation of cultures with excitatory amino acids increased the resistance of the microtubular cytoskeleton to depolymerization by nocodazole. Again double-labelling experiments demonstrated an increased association between neurofilaments and MAP2 immunofluorescence. Previous results suggested that the stability of the neuronal cytoskeleton could be modulated by glutamate receptors acting through an increased binding of MAP2 to microtubules. From the results presented here, we further suggest that cross-linking of neurofilaments to microtubules may also play a role in this process.     

Immunohistochemical detection of osteopontin in the spinal cords of mice with Theiler's murine encephalomyelitis virus-induced demyelinating disease

The spinal cords of mice that were infected with the BeAn 8386 strain of Theiler's murine encephalomyelitis virus (TMEV) were studied to elucidate the involvement of osteopontin in the course of TMEV-induced demyelination. Immunohistochemistry showed staining for osteopontin in the vessels of the normal spinal cords, and more intense immunoreactivity in the vessels within the demyelinating lesions. Intense osteopontin immunoreactivity was observed in the cell bodies, as well as in the extracellular space of the demyelinating lesions, where some glial cells, which included activated microglia/macrophages, were also immunopositive for osteopontin. These findings suggest that osteopontin is upregulated in the demyelinating spinal cord, and that osteopontin from either microglia or astrocytes may be involved in the chemotaxis of inflammatory cells and astrocytes, which ultimately leads to chronic inflammation and astrogliosis in this model system.     

Immunolocalization of the arachidonic acid and mechanosensitive baseline traak potassium channel in the nervous system

TRAAK is the sole member of the emerging class of 2P domain K+ channels to be exclusively expressed in neuronal cells. TRAAK produces baseline K+ currents which are strongly stimulated by arachidonic acid and by mechanical stretch, and which are insensitive to the classical K+ channel blockers tetraethylammonium, Ba2+, and Cs+. This report describes the immunolocalization of TRAAK in brain, spinal cord, and retina of the adult mouse. The most striking finding is the widespread distribution of the TRAAK immunoreactivity, with a prominent staining of the cerebellar cortex, neocortex, hippocampus, dentate gyrus, subiculum, the dorsal hippocampal commissure, thalamus, caudate-putamen, olfactory bulb, and several nuclei in the brainstem. Virtually all neurons express TRAAK, and the highest immunoreactivity was seen in soma, and to a lesser degree in axons and/or dendrites in most areas in brain and spinal cord. In the retina, the TRAAK protein is concentrated to the soma of ganglion cells and to the dendrites of all other neurons. Taken together, these results show a wide distribution of TRAAK, a mechanosensitive and arachidonic acid-stimulated neuron-specific baseline K+ channel, in brain, spinal cord and retina.     

慢性压迫性脊髓损伤时兴奋性氨基酸变化的实验研究

本研究目的是观察在慢性脊髓压迫性损伤时 ,脊髓组织兴奋性氨基酸免疫组织化学的变化及其与脊髓病理变化之间的关系。用健康家兔 16只 ,随机分为三组 :A组 ,正常对照组 ;B组 ,手术对照组 ;C组 ,慢性压迫组。采用泛影葡胺囊逐级压迫复制慢性脊髓压迫动物模型 ,C组家兔逐级压迫脊髓 12周。取 A、B,C三组家兔脊髓压迫节段或相当于压迫节段和与其相邻的吻、尾侧节段 ,应用 Nissl染色观察脊髓的病理变化并用免疫组织化学方法对脊髓组织谷氨酸、天门冬氨酸分布特点和含量变化进行分析。结果表明 :C组家兔脊髓压迫节段谷氨酸和天门冬氨酸免疫组化染色光密度较 A组、B组各个脊髓节段增高 ,同时 C组脊髓压迫节段较本身吻、尾侧两个相邻脊髓节段光密度也都增高 ;B组与 A组各节段相比无明显差异。 Nissl染色可见 C组脊髓压迫节段前角运动神经元萎缩 ,尼氏体淡染 ,脱颗粒 ;并伴有脊髓灰质胶质细胞增生。B组与 A组表现正常。兴奋性氨基酸含量升高与脊髓病理改变出现在同一脊髓节段。结果提示 :在慢性脊髓压迫时 ,兴奋性氨基酸含量增加 ,在脊髓继发性损害中起重要作用     

Neurokinin-1 Receptor Immunoreactive Neuronal Elements in the Superficial Dorsal Horn of the Chicken Spinal Cord: With Special Reference to Their Relationship with the Tachykinin-containing Central Axon Terminals in Synaptic Glomeruli

Synaptic glomeruli that involve tachykinin-containing primary afferent central terminals are numerous in lamina II of the chicken spinal cord. Therefore, a certain amount of noxious information is likely to be modulated in these structures in chickens. In this study, we used immunohistochemistry with confocal and electron microscopy to investigate whether neurokinin-1 receptor (NK-1R)-expressing neuronal elements are in contact with the central primary afferent terminals in synaptic glomeruli of the chicken spinal cord. We also investigated which neuronal elements (axon terminals, dendrites, cell bodies) and which neurons in the spinal cord possess NK-1R, and are possibly influenced by tachykinin in the glomeruli. By confocal microscopy, NK-1R immunoreactivities were seen in a variety of neuronal cell bodies, their dendrites and smaller fibers of unknown origin. Some of the NK-1R immunoreactive profiles also expressed GABA immunoreactivities. A close association was observed between the NK-1R-immunoreactive neurons and tachykinin-immunoreactive axonal varicosities. By electron microscopy, NK-1R immunoreactivity was seen in cell bodies, conventional dendrites and vesicle-containing dendrites in laminae I and II. Among these elements, dendrites and vesicle-containing dendrites made contact with tachykinin-containing central terminals in the synaptic glomeruli. These results indicate that tachykinin-containing central terminals in the chicken spinal cord can modulate second-order neuronal elements in the synaptic glomeruli.     

Expression of Fos-like immunoreactivity in the brain and spinal cord of rats following middle cerebral artery occlusion

 This study examined c-fos protein expression in the brain and spinal cord of rats following permanent occlusion of the middle cerebral artery (MCA) above the rhinal fissure. At 1 h after right-sided MCA occlusion, Fos-like immunoreactivity (Fos-LI) was detected in neurons not only in the ipsilateral cerebral cortex but also in the spinal cord. In the latter, Fos-LI was localized in the nucleus and perikarya of neurons in the grey matter, notably the large motor neurons in the ventral horn. Fos-LI was most intense at 2–4 h, but became undetectable after 48 h in the cerebral cortex and 72 h in the spinal cord. In sham-operated animals, Fos-LI was almost undetectable or virtually absent. It was also not detected in the core territory supplied by the MCA at any time points after arterial occlusion. When the ischaemia-induced neuronal damage in both the cerebral cortex and spinal cord was evaluated by Nissl staining, some neurons appeared atrophic. We conclude that the induction of Fos-LI in neurons of the cerebral cortex and spinal cord is linked respectively to early onset–short stimulation and persistent excitatory or disinhibition phenomenon as a result of focal ischaemic brain injury. Received: 16 September 1996 / Accepted: 29 November 1996