Lectins demarcate the barrel subfield in the somatosensory cortex of the early postnatal mouse

Plant lectins were used to examine the disposition of glycosylated molecules in vibratome sections through the barrel subfield of mouse somatosensory cortex at selected times during postnatal development. The peroxidase conjugates of peanut agglutinin (PNA, specific for N-acetylgalactosamine), concanavalin A (specific for mannose), and wheat germ agglutinin (specific for N-acetylglucosamine and N-acetylneuraminic acid) were used to study lectin binding in aldehyde-fixed tissue sections of cortex. Following peroxidase cytochemistry and light microscopy, it was found that all three lectins bound in the region of the barrel subfield as early as postnatal day 3 (day of birth = postnatal day 1). The lectins bound to the prospective sides and/or septae of individual barrels in preference to the prospective hollows. This lectin demarcation of the barrel field occurred prior to the detection of this region with cresyl violet staining and was still demonstrable on postnatal day 6, when the individual barrels became discernible with cresyl violet. This suggests that the lectin binding material is present before the barrel field becomes a fully formed and organized region. A decrease in lectin affinity for binding sites in these tissue sections occurs during postnatal development (Cooper and Steindler: Soc. Neurosci. (Abstr.) 10: 43a, '84) and this study demonstrates that lectins do not delineate the barrel field of more mature animals (2-3 months old), whereas barrels can be detected with cresyl violet at this time. A preliminary electron microscope analysis of the postnatal day 6 somatosensory cortex demonstrates that the lectin PNA binds to elements of the forming neuropil and also to Golgi apparatus intermediate saccules in neuronal cells. The prospective barrel field can be detected with lectins during a critical period in development in which alterations can occur in the barrel field in response to peripheral deprivation (Jeanmonod et al: Neuroscience 6:1503-35, '81) and therefore we suggest that the glycans visualized with lectin-peroxidase conjugates denote possible candidates for molecules involved in shaping barrel structure.     

Afferent-boundary interactions in the developing neostriatal mosaic.

The caudate-putamen (neostriatum) of the mammalian basal ganglia is composed of two neurochemically distinct compartments termed patch (island, striosome) and matrix that overall contribute to a mosaic organization. In the present study, the distribution of the developmentally regulated extracellular matrix molecule tenascin, as well as several other neural cell adhesion molecules, was examined in the neostriatal mosaic of the early postnatal mouse and compared with tyrosine hydroxylase distribution following partial destruction of the dopaminergic nigrostriatal projection. During normal neostriatal development, tenascin is most dense within the matrix compartment and highly concentrated in boundaries around patches. This pattern is apparent on embryonic day 18, and for the most part disappears by postnatal day 12. Tenascin immunoreactivity is altered in the neostriatum following lesions of the nigrostriatal pathway in the first postnatal week revealed by an overall reduced expression of this molecule and a marked reduction in tenascin staining of boundaries at the interface of tyrosine hydroxylase-rich patch and tyrosine hydroxylase-poor matrix compartments. When compared to tyrosine hydroxylase immunoreactivity, other cell adhesion molecules tested failed to show altered intensities and patterns of immunoreactivity within the neostriatum after similar lesions. Reduced levels of tenascin in the lesioned neostriatum, in register with altered levels of tyrosine hydroxylase immunostaining of dopaminergic inputs, suggests that axons may affect the expression of particular recognition molecules in their target structures. The fact that boundaries are malleable can be related to afferent-induced plastic events in the differentiation of cellular elements in the developing nigrostriatal system.     

Glial and glycoconjugate boundaries during postnatal development of the central nervous system

The localization of glycosylated molecules and glia has been studied during early postnatal development in the mouse central nervous system (CNS) using autoradiographic detection of radiolabeled fucose incorporation, and in sections processed either for histochemistry or immunocytochemistry following binding of labeled lectins or an antibody to glial fibrillary acidic protein. Radiolabeled sugar incorporation, lectin binding of glycoconjugates, and glial labeling all reveal borders between nuclei within the diencephalon, midbrain, and brainstem through the first postnatal week. Glycoconjugate and glial boundaries exist throughout the CNS during pattern formation events, and they also are seen in relation to fine aspects of developing functional organization within individual structures (e.g. segmentation associated with the representation of mystacial vibrissae within the brainstem trigeminal complex). The observation that each of the probes employed in this study fails to label boundary organization during later postnatal times suggests that the distribution and chemistry of the glial/glycoconjugate network are dynamic, and they change in accordance with distinct maturational states of the nervous system.     

Wheat germ agglutinin binding sites in the adult mouse cerebellum: light and electron microscopic studies

The binding properties of derivatized wheat germ agglutinin (WGA) have been examined in fixed tissue sections from the adult mouse cerebellum and also in axonal tracing paradigms following cerebellar injections. The aim of these studies is to begin to distinguish the roles different binding sites may play in generating diverse biological activities which lead to neuronal uptake and axonal transport of lectins or glycoconjugates. Vibratome sections from aldehyde-fixed cerebellum were incubated in N-[acetyl-3H] WGA or WGA conjugated to horseradish peroxidase (WGA-HRP). Sections from this in vitro binding paradigm and those from cerebellar pressure injection cases using those tracers (in vivo binding paradigm) were processed for light microscopic autoradiography, histochemistry, and electron microscopy. Blocking experiments were also performed with various sugar haptens to confirm the binding specificity of these lectin preparations. Light microscopy of lectin binding patterns within the cerebellar cortex has revealed that both derivatized WGA preparations bind most intensely to the molecular layer. Within the deep cerebellar nuclei, binding is unique and produces a punctate delineation of cell bodies and dendrites. Electron microscopy revealed that these binding sites are associated with glial processes which abut the plasma membrane of deep nuclei cells. Cerebellar WGA-HRP injection sites contain labeled profiles involved in uptake and axonal transport of the labeled lectin (e.g., multivesicular and dense bodies) in addition to label associated with synapses, glia, undetermined components of the extracellular space, and neuronal plasma membranes. These sites are therefore presumed to possess a high affinity or capacity for binding derivatized WGA. Binding studies performed here thus reveal, for the first time, the existence of discrete glial sites that display an extraordinary attraction for lectins such as WGA. The roles such glial glycoconjugates play in diverse biological activities including neuronal uptake and transport of macromolecules need further study.     

Selective lectin binding of the developing mouse retina

A battery of eight lectins with different carbohydrate specificities was used to study changes in glycoconjugate expression during cell differentiation in the mouse retina. The lectins tested included concanavalin A (Con A), wheat germ agglutinin (WGA), soybean agglutinin (SBA), peanut agglutinin (PNA), Ulex europaeus agglutinin (UEA), Ricinus communis agglutinin I (RCA), Dolichos biflorus agglutinin (DBA), and Limulus polyphemus agglutinin (LPA). Unfixed frozen sections of adult and early postnatal mouse retina were treated with fluorescein isothiocyanate-conjugated lectins and examined by fluorescence microscopy. The results showed selective lectin binding in both cellular and synaptic retinal layers of the adult mouse and throughout postnatal development. In general, an increase in intensity of fluorescent lectin staining during retinal development was observed for Con A, WGA, DBA, LPA, RCA, and PNA. This suggests an increase in the expression or accessibility of carbohydrate moieties during development. SBA and UEA showed little to no binding to adult or neonatal retina. Retinal vasculature was intensely stained by RCA, both during development and in the adult. All lectins binding to adult or neonatal retinal layers showed some degree of reactivity with the inner segment region of photoreceptor cells. However, only Con A, PNA and WGA bound to photoreceptor outer segments, suggesting significant differences in the glycosylated components of inner and outer segment membranes. PNA bound specifically to a subpopulation of photoreceptor cells and to discrete regions within the outer synaptic layer. The pattern of PNA binding suggests that this lectin binds preferentially to cone photoreceptor inner and outer segments and cone synaptic pedicles rather than to rod photoreceptor cells. This marked specificity of PNA binding suggests that it may provide a basis for the physical separation of cone and rod photoreceptor cells.     

Developmental stage-specific changes in lectin binding to mouse cerebellar cells in vitro

Eleven fluorescein isothiocyanate-conjugated (FITC) lectins, each with distinct carbohydrate-binding properties, were used to assess cell surface glycoconjugates of embryonic and early postnatal cerebellar cells in vitro. Fluorescence staining of embryonic day 13 (E13) cerebellar cells with FITC Ricinus communis agglutinin diminished markedly between 24 and 72 hr in vitro. No staining of postnatal day 0 (P0) or postnatal day 7 (P7) cells was observed with FITC Ricinus communis agglutinin. A similar, but less pronounced decrease in FITC concanavalin A, FITC Lens culinaris, and FITC wheat germ agglutinin was observed between embryonic day 13 and birth. No specific staining of E13, P0, or P7 cultures was observed with FITC peanut agglutinin, FITC Dolichos bifloris agglutinin, FITC soybean agglutinin, FITC Wistaria floribundis agglutinin, FITC Phaseolus vulgaris agglutinin, FITC Limulus polyphemus agglutinin, or FITC Ulex europaeusI agglutinin. Similar results were obtained with 125I-lectin binding assays. Ricinus communis 125-I-agglutinin binding decreased dramatically between embryonic day 13 and birth. Less pronounced decreases were observed in 125I-concanavalin A and wheat germ 125I-agglutinin binding. Very low levels of soybean 125I-agglutinin or Ulex europaeusI 125I-agglutinin were bound by either embryonic or early postnatal cerebellar cells in vitro.     

Abnormal glial and glycoconjugate dispositions in the somatosensory cortical barrel field of the early postnatal reeler mutant mouse

During early postnatal development in reeler mutant mice, lectin binding delineates prospective abnormal barrels as they will appear in the adult mutant somatosensory cortex. Glial fibers also may be more condensed within fascicles in developing reeler barrels. These fibers also appear to be misaligned, coursing predominantly in the tangential plane within the abnormal reeler barrel sides as opposed to having a radial orientation as seen in normal mouse barrels. The thalamic barreloid complex, however, reveals a disposition of glycoconjugates that is completely normal in reeler. Thus, there are anomalies in glia and associated glycoconjugates during mainly cortical development in the reeler mutant mouse that might be related to the primary action of the abnormal gene.     

Minimal connectivity between neostriatal transplants and the host brain

The present study sought to determine if axonal connectivity is established between neostriatal transplants and the host brain during the first two months of graft development. Cell suspensions of embryonic neostriatum were transplanted into the adult rat neostriatum lesioned previously by kainic acid. After 1-2 months, injections of horseradish peroxidase conjugated with wheat germ agglutinin (HRP) were made either within the graft, into adjacent host neostriatum or the host ventral midbrain. In animals with HRP injection sites restricted to the graft no retrograde or anterograde label was found in the host brain. However, both anterograde axon label and retrogradely labelled neurons were found in areas within the transplant but distal to the injection site. Neither ventral midbrain nor host neostriatal HRP injections resulted in any significant anterograde or retrograde label within the graft. These results demonstrate a lack of connectivity between neostriatal grafts and the host brain 1-2 months post-transplantation but an ability of grafted neurons to project to different locations within the transplant. Therefore, transplanted neostriatal neurons develop for the first two months in the absence of normal neostriatal afferent and efferent connections.     

Postnatal localization and morphogenesis of cells expressing the dopaminergic D2 receptor gene in rat brain: Expression in non-neuronal cells

The cellular localization of the dopaminergic D2 receptor (D2R) mRNA and protein was determined during postnatal development, from birth to 35 days, in the rat neostriatum by in situ hybridization histochemistry and immunohistochemistry. To localize and identify more precisely the morphology of cells expressing the D2R mRNA, nonradioactive, digoxigenin in situ hybridization was performed. Throughout this period of development, D2R mRNA and protein were widely expressed by neostriatal cells, adjoining forebrain cells and small cellular processes. Within morphologically identifiable neurons, the expression of the D2 receptor appeared to occur after cell division ceased. D2R gene expression appeared during neuronal migration and followed the developmental pattern of neuronal settling within the neostriatum. Both D2R mRNA and protein appeared to colocalize in neostriatal cells and the labeling of both appeared to accumulate within the cells progressively with age. The structural phenotypes of neostriatal neurons bearing D2R mRNA and protein were diverse throughout postnatal development. The most frequently stained cells were a heterogeneous group of medium spiny and aspiny neurons. Large cells corresponding to aspiny neurons were less frequently stained. Both phenotypes exhibited considerable postnatal growth of their cell bodies. In addition to neurons, other cell types were also observed to express the D2R mRNA and protein over the developmental period studied. These other cells included patches of ciliated ependymal cells lining the lateral ventricles and many interfascicular oligodendroglia of forebrain fiber tracts. These results demonstrate the unexpected expression of the dopaminergic D2 receptor in non-neuronal cells within the brain. They provide a novel morphologic suggestion that the dopaminergic D2 receptor may support unrecognized, nonsynaptic functions in specific non-neuronal cell populations in the nervous system. J. Comp. Neurol. 391:87–98, 1998. © 1998 Wiley-Liss, Inc.     

Guidance of Thalamocortical Axons by Growth-promoting Molecules in Developing Rat Cerebral Cortex

Substrate-bound guidance cues play an important role during the development of thalamocortical projections. We used time-lapse video microscopy to study the growth behaviour of thalamic axons on different substrates. On embryonic cortical membranes and on a pure laminin substrate, thalamic fibres advanced relatively slowly (∼15 μm/h) and on average their growth cones retracted transiently every ∼5 h. In contrast, on membranes prepared from early postnatal cortex, thalamic fibres grew twice as fast and spontaneous growth cone collapse occurred ∼8 times less often. Experiments in which we used the sugar-binding lectin peanut agglutinin or heat inactivation to change the membrane properties indicated that these differences are due to growth-supporting molecules on postnatal cortical membranes. When offered a choice between embryonic and postnatal cortical membranes, thalamic axons preferred the postnatal membrane substrate. Time-lapse imaging revealed that borders between these two substrates effectively guided thalamic fibres, and in most cases axons changed their direction without collapse of the growth cone. Our results suggest that thalamic axons can be guided by the spatial distribution of growth-promoting molecules in the developing cortex.     

Lectin histochemistry of the metathoracic ganglion of the locust Schistocerca gregaria before and after axotomy of the tympanal nerve

The thoracic ganglia of insects exhibit a highly ordered organization. It seems possible that the information underlying the emergence of this order during development and its maintenance throughout insect life is given via a distinct pattern of molecules distributed within the ganglion. The question we asked was whether the adult insect ganglion is subdivided by the distribution of specific carbohydrates and furthermore whether or not this distribution changes during degeneration and regeneration of neurons. In order to determine the normal carbohydrate distribution, we stained sections of the intact metathoracic ganglion of the locust Schistocerca gregaria with fluorescence-coupled lectins. We succeeded in labeling three sensory neuropil areas with either peanut agglutinin (PNA): Phaseolus vulgaris erythrolectin (PVE), soybean agglutinin, wheat germ agglutinin (WGA), or Vicia villosa agglutinin. Apart from this, PNA, WGA, and succinylated WGA also selectively labeled some neuronal cell bodies, including dorsal unpaired median neurons. Datura stramonium lectin (DSL), Griffonia simplicifolia lectin II, and Solanum tuberosum lectin (STL) bound to glial cells or glia surrounding extracellular matrix. A few lectins stained all structures within the ganglion; some showed no binding at all. In the second part of our study, we tested whether carbohydrates were differentially regulated during transient deafferentation after the axotomy of the tympanal nerve. Binding of PNA and PVE within the auditory neuropil did not change. However, binding of the two glia-associated markers, DSL and STL, clearly differed from that found in intact animals; they bound transiently (day 3–4 until day 10–20 post-surgery) to axonal tracts and neuropils of the axotomized sensory afferents. J. Comp. Neurol. 387:255–265, 1997. © 1997 Wiley-Liss, Inc.     

Patterns of tachykinin expression and localization in developing feline neostriatum

The development of tachykinins in the neostriatum was determined qualitatively in order to characterize the ontogeny of an early-forming neostriatal peptidergic system. Tachykinins were detected by immunohistochemistry in fetal, postnatal, and adult cats. Neostriatal cells and neurites expressed tachykinins as early as fetal age 30 and increased in frequency progressively with age. Initial tachykinin expression occurred in neostriatal neurons during their postmitotic migration. In the head of the caudate nucleus, clusters of tachykinin-containing cells and fibers formed between fetal days 35 and 45, when the distribution of labeled neurons changed from a dispersed to an aggregated pattern. Between fetal days 45 and 50, tachykinin-rich neuronal clusters increased in frequency and were distributed throughout the rostral caudate nucleus. In contrast to neurons in clusters, neurons in the complementary neuropil expressed tachykinins largely postnatally. Postnatal morphological maturation of tachykinin-containing neurons paralleled the morphogenesis of medium spiny neostriatal cells. In addition, the caudate nucleus and putamen followed different spatiotemporal gradients of tachykinin expression. These results indicate that tachykinins are expressed in neostriatal neurons during the early ontogeny of the neostriatum and may function as trophic factors before synaptogenesis.     

Lectin histochemistry in brains with juvenile form of neuronal ceroid-lipofuscinosis (Batten disease)

Summary Defective ultilization of dolichols in the synthesis of glycoprotein leads to an accumulation of the storage, pigment ceroid lipofuscin, containing high-mannose-type glycoconjugates, in brains affected by neuronal ceroid-lipofuscinoses (NCL). We have employed lectin histochemistry to study the distribution of such compounds and the composition of other glycoconjugates in brains of patients with a juvenile form of the disease (JNCL). Concanavalin A detected the high-manose glycoconjugates in all neurons of brains with JNCL, in lipofuscin-containing neurons of aging brains and in some neurons of age-matched control brains. Three other lectins (soybean agglutinin, Peanut agglutinin and Ulex europaeus agglutinin-I) recognized sugar moities in neurons containinglipofuscin in patients only with JNCL and not in age-matched or aging brains. The results led to the conclusion, that the binding pattern of these three lectins may differentiate between storage materials of NCL and aging brains.Supported by NIH Grant No. 5P5ONS23717D. Maslinska is a visiting scientist from Medical Research Centre, Polish Academy of Science, Warsaw, Poland     

Enkephalin-positive and acetylcholinesterase-positive patch systems in the superior colliculus have matching distributions but distinct developmental histories

Histochemical stains for acetylcholinesterase activity and enkephalin-like immunoreactivity both demonstrate a high degree of patterning in the superior colliculus, particularly in the intermediate and deep layers. Both markers occur predominantly in the neuropil of these layers, and both are principally distributed in distinct macroscopic compartments. We report here that patches of heightened acetylcholinesterase activity correspond to patches of high enkephalin-like immunoreactivity. The two markers thus delineate largely the same domain in the intermediate and deep layers. The most prominent zones of staining for enkephalin-like peptide and for acetylcholinesterase also coincided in the dorsolateral periaqueductal gray matter. These findings suggest a close interlocking of one or more acetylcholinesterasecontaining systems with one or more pathways related to endogenous opioids in the superior colliculus. As the acetylcholinesterase expression in the patches is known to match in detail choline acetyltransferase expression, our results also suggest the possibility of local cholinergicopiatergic interactions. In some sections, blood vessels associated with enkephalin-rich and acetylcholinesteraserich patches extended beyond the colliculus into the periaqueductal gray matter, where they again became surrounded by dense fibrous labeling. This pattern suggests that neurohumoral signal exchange might occur through blood vessels even in a sensory-motor structure such as the colliculus. In a postnatal developmental series of kitten brains we found that enkephalin-like immunoreactivity was already distinctly compartmental in the intermediate layers at birth and continued to show this distribution throughout postnatal development. By contrast, acetylcholinesterase staining was nearly homogeneous at birth and became compartmental gradually during the first postnatal weeks. Thus, despite the eventual near coincidence of the enkephalinrich and acetylcholinesterase-rich compartments of the superior colliculus, they mark systems that follow distinct programs of neurochemical development. © Wiley-Liss, Inc.     

Regulation of a beta-galactoside-binding lectin and potential ligands during postnatal maturation of rat brain.

Variations in expression and activity of a beta-galactoside-specific lectin were quantified during postnatal maturation of the rat brain. Lectin expression, estimated from enzymatic immunoassay data, and lectin activity, evaluated by rabbit erythrocyte agglutination, are higher in the brains of young animals (5 days after birth) than in older ones (2 months of postnatal life). Concurrently, modifications in glycosylation during cellular differentiation were detected by affinoblotting using a biotinylated derivative of a beta-galactoside-specific brain lectin. This study shows that membrane and cytosolic glycoconjugates of the rat brain bear appropriate beta-galactoside moieties which may be recognized by an endogenous lectin expressed in the tissue itself in relation to brain maturation. The observed variations in the expression of lectin and complementary glycoconjugates can be correlated with significant events of rat brain development.     

Carbohydrate components recognized by the cone-specific monoclonal antibody CSA-1 and by peanut agglutinin are associated with red and green-sensitive cone photoreceptors

Previous investigations have demonstrated that the monoclonal antibody CSA-1 and peanut agglutinin label specifically cone photoreceptor cells. In the present study, we compared the binding of CSA-1 and peanut agglutinin to that of the monoclonal antibodies COS-1 and OS-2, which have been shown to recognize the red/green- and blue-sensitive cone visual pigments, respectively. Using lectin and immunocytochemistry on serial semithin sections of the pig retina, we have demonstrated in the present study that both CSA-1 and peanut agglutinin label specifically the red-, and green-sensitive, but not the blue-sensitive cone cell outer segments. Peanut agglutinin does bind, however, to the cone matrix sheaths associated with all three types of cones. These observations support the idea that red-, and green-sensitive cone cells share some common molecular epitopes and may represent a differentiation line of cones, considerably different from that of blue-sensitive cones.     

Continuous amphetamine administration induces tyrosine hydroxylase immunoreactive patches in the adult rat neostriatum

Continuous 3-day administration of d-amphetamine sulfate via a subcutaneous minipump induced the appearance of tyrosine hydroxylase immunoreactive patches in the neostriatum of adult Sprague-Dawley and Long-Evans rats at doses (greater than 20 mg/kg/day) that also produced axonal terminal degeneration as evidenced by Fink-Heimer silver grain deposition. The tyrosine hydroxylase patches coincided with striosomes identified by Leu-enkephalin immunoreactivity on adjacent sections. Sham-operated control, naive control, low dose amphetamine- (less than 15 mg/kg/day) and cocaine- (less than 125 mg/kg/day, IV) treated rats did not show tyrosine hydroxylase neostriatal patches nor axonal degeneration. These results suggest that the diffuse neostriatal dopamine system may be more susceptible to the neurotoxic, degenerative action of continuously administered amphetamine than is the islandic dopamine system.     

Lectin binding sites and anionic components related to differentiation in the prenatal rat cerebral cortex

The location of lectin binding sites and of anionic components was studied in the embryonic rat cerebral cortex after the formation of the cortical plate at embryonic day 18. The cortical layers advanced in differentiation, i.e. the sub-plate region and the marginal zone, showed a predominant staining with peroxidase conjugates of wheat germ agglutinin (WGA), peanut agglutinin (PNA), and after immunocytochemical detection of PNA binding sites. This pattern was obtained also with the colloidal iron hydroxide staining method. In contrast to this, the binding of concanavalin A and of succinylated WGA did not reveal a prevalent staining of the sub-plate region and the marginal zone. The further histochemical analysis of the substances responsible for the selective staining of these layers was performed by lipid extractions and by enzymatic treatment of the tissue sections with trypsin, hyaluronidase or neuraminidase prior to the binding of lectins or colloidal iron. The results obtained indicated high concentrations of sialylated galactosylglycoproteins in coexistence with glycosaminoglycans. Electron microscopy was performed with peroxidase conjugates of WGA and PNA. Binding sites of both of the lectins in the sub-plate region and in the marginal zone were located mainly at cell surfaces of the different cellular structures. The most intensive binding of WGA and PNA was detected at the surface membranes and at intracellular material of amoeboid microglial cells and astrocyte-like cell processes. It can be concluded that in distinct brain areas during early differentiation specific glycoproteins in coexistence with glycosaminoglycans are situated at, or associated with cell surfaces in high concentrations. The identical histochemical features previously described in mesenchymal tissues suggest that these glycoconjugates might be related to common morphogenetic processes in which non-neuronal cells of brain and body are specifically involved.     

Histological and ultrastructural evidence that D-amphetamine causes degeneration in neostriatum and frontal cortex of rats

D-Amphetamine sulfate, continuously administered for 3 days subcutaneously via an implanted minipump, induced neural degeneration in Long-Evans and Sprague-Dawley rats at doses between 20 and 60 mg/kg/day. Using Fink-Heimer silver staining, axonal degeneration was detected in the neostriatum and the dorsal agranular insular cortex and degenerating pyramidal cells were observed in portions of the somatosensory neocortex in both strains. In contrast, dense axonal degeneration largely confined to layers 2 and 3 of frontal motor areas (Fr1, Fr2 and Fr3 of Zilles36) with occasional degenerating cells was seen reliably in Long-Evans rats but rarely in Sprague-Dawley rats. In the electron microscope, cortical degeneration consisted mainly of disrupted cell bodies and dark processes, including axons making asymmetric synapses. Damage in all cortical areas represents damage to non-monoamine neurons and processes since tyrosine hydroxylase and serotonin immunolabeling were normal. In contrast, the damage in neostriatum probably includes damage to dopamine axonal terminals since tyrosine hydroxylase immunolabeling was patchy with many swollen and distorted labeled axons. Serotonin and Leu-enkephalin labeling were normal. Electron microscopy confirmed that the neostriatum contained many tyrosine hydroxylase-labeled axons that were swollen and disrupted, although other labeled processes made normal symmetric synapses onto spines and dendrites. Additional degeneration found only in amphetamine-treated rats included many dark, shrunken profiles. Some of these appeared to be astrocytic processes and a few were myelinated axons, suggesting that some non-monoamine, possibly cortical afferents, are also degenerating in the neostriatum. Since similar degrees of behavioral activation, weight loss and lethality were seen in both strains, a genetic predisposition constrain amphetamine-induced motor cortex damage but not neostriatal damage.     

Immunochemical quantification of glycoconjugates in serum and cerebrospinal fluid of amyotrophic lateral sclerosis patients

Glycoconjugates in the serum of 73 patients with amyotrophic lateral sclerosis (ALS), 21 cases of other motor neuron diseases and 20 healthy controls were determined. Cerebrospinal fluid (CSF) was studied in 64, 7 and 10 of these subjects, respectively. The level of sialic acid containing glycoconjugates, detected by Maakia amurensis agglutinin (MAA), was decreased in the serum of 61.6% of the ALS patients, while in the CSF it was decreased, on average, in 75% of these cases. Only in single ALS cases was the concentration of these glycoconjugates increased. There was no correlation between the content of MAA-labelled glycoconjugates both in serum and CSF and the titre of sialic acid containing anti-GM1 gangliosides. The glycoconjugates, detected by peanut agglutinin (PNA) which recognizes the disaccharide galactose beta(1-3)N- acetylgalactosamine (GGN), were decreased in the serum of 78.1% of ALS patients, while in CSF they were increased in 54.7% of these cases. There was no correlation between the concentration of PNA-labelled glycoconjugates both in serum and CSF as well as the titre of antibodies against GGN-containing anti-GM1 and anti- AGM1 gangliosides. Changes in the level of the MAA- and PNA- labelled glycoconjugates, as well as the titre of anti-GM1 and anti-AGM1 gangliosides antibodies were not specific for ALS. They were also observed in some cases of other motor neuron diseases. The low level of the lectin-labelled glycoconjugates in serum and partly in CSF of the majority of ALS patients is possibly the consequence of their accelerated clearance and/or specific inactivation by the formation of immune complexes or epitope binding. Degeneration of neurons and muscle cells could also be responsible. The relatively low incidence of high anti- glycolipids antibodies titre may be, at least partly, connected with the low concentration of the appropriate antigens. The increased content of PNA-labelled glycoconjugates in the CSF of the majority of ALS patients, together with the low incidence of high titre of antibodies against the appropriate glycolipids, could indicate that in CSF this lectin binds to the GGN epitope of glycoproteins rather than to the GGN epitope of glycolipids.