Distribution of an endogenous lectin in the developing chick optic tectum.

We determined the cellular localization of an endogenous lectin at various times during the development of a well-characterized region of chick brain, the optic tectum. This lectin is a carbohydrate-binding protein that interacts with lactose and other saccharides, undergoes striking changes in specific activity with development, and has previously been purified by affinity chromatography from extracts of embryonic chick brain and muscle. Cellular localization in the tectum was done by indirect immunofluoresecent staining, using immunoglobulin G derived from an antiserum raised against pure lectin. No lectin was detectable in the optic tectum examined at 5 days of embryonic development. From approximately 7 days of development, neuronal cell bodies and fibers were labeled by the antibody; and extracts of tectum contained hemagglutination activity that could be inhibited by lactose or by the antiserum. Lectin remained present in many tectal neuronal layers after hatching; but in 2-month-old chicks it was sparse or absent in most of the tectum except for prominent labeling of fibers in the stratum album centrale. The initial appearance of lectin in the optic tectum was not dependent on innervation by optic nerve fibers since bilateral enucleation during embryogenesis did not affect it. Lectin was detectable on the surface of embryonic optic tectal neurons dissociated with a buffer containing EDTA.

Brain peptides and glial growth. II. Identification of cells that secrete glia-promoting factors.

Glia-promoting factors (GPFs) are brain peptides which stimulate growth of specific macroglial populations in vitro. To identify the cellular sources of GPFs, we examined enriched brain cell cultures and cell lines derived from the nervous system for the production of growth factors. Ameboid microglia secreted astroglia-stimulating peptides, while growing neurons were the best source of the oligodendroglia-stimulating factors. These secretion products co-purified by gel filtration, anion exchange chromatography, and reverse-phase high performance liquid chromatography with GPFs isolated from goldfish and rat brain. Our findings suggest that glial growth in the central nervous system is regulated in part by a signaled release of peptides from specific secretory cells.

( 3 H)lysergic acid diethylamide: cellular autoradiographic localization in rat brain.

Intravenous administration of [(3)H]lysergic acid diethylamide(LSD) to rats resulted in accumulation of the drug in the brain within 15 minutes. Autoradiographic methods were used to differentiate free and bound [(3)H]LSD in brain tissue. Free [(3)H]LSD was generally distributed in the pituitary and pineal glands, cerebellum, hippocampus,and choroid plexus. Bound [(3)H]LSD was localized in neurons of the cortex, caudate nucleus, midbrain, and medulla,as well as in choroid plexus epithelium.

Immunocytochemical localization of gamma-aminobutyric acid (GABA) in the cat superior colliculus.

This paper reports the pattern of labeling in the cat superior colliculus produced by an antiserum raised against BSA-conjugated gamma aminobutyric acid (GABA) and visualized by light and electron microscope immunocytochemistry. Neuropil labeling was densest within the zonal and superficial gray layers but was also found in the deep layers. Neurons labeled by the GABA antibody were also most dense within the zonal and superficial gray layers, although many labeled neurons were also found in the deeper layers. The ratio of labeled to unlabeled cells varied from an average of 45% in the superficial subdivision and the intermediate gray layer to less than 30% in the deeper laminae. Almost all intensely labeled cells were small (mean area = 127 micron 2) and had varied morphologies. Several types of labeled cell were observed with the electron microscope. One type had a horizontal, fusiform cell body and a deeply invaginated nucleus. Another type had a small round or ovoid cell body with cytoplasm clumped at one end. Labeled cells with other morphologies were also occasionally seen. No labeled glial cells were found. Two types of vesicle-containing dendrite were stained by the GABA antibody. One type had loose accumulations of small synaptic vesicles and often received input from retinal terminals. Another type had spines also containing small synaptic vesicles. Labeled dendrites without synaptic vesicles were also seen frequently. Putative axon terminals labeled by the GABA antibody had densely packed synaptic vesicles and formed symmetric synaptic contacts. Labeled myelinated axons were also commonly found. These results confirm those using uptake of tritiated GABA (Mize et al.: J. Comp. Neurol. 202:385-396, '81, J. Comp. Neurol, 206:180-192, '82) in that two of the same classes of GABA neuron, horizontal I and granule I cells, were identified in the superficial laminae. However, the GABA antiserum used in this study also revealed a third class of GABA neuron with vesicle-containing spines. The antiserum also labeled a significant number of putative GABAergic neurons located in the deep subdivision of the cat superior colliculus which were not previously recognized by using transmitter autoradiography.

Anatomical and physiological localization of visual and infrared cell layers in tectum of pit vipers.

Visual and infrared cell layers were identified in the tectum of the pit vipers Crotalus viridis and Sistrurus melitus. Histologic reconstructions of 48 lesions utilizing the Prussian Blue technique were correlated with micrometer depth readings for 251 visual, infrared and bimodal single unit recordings. The visual cell layer extends caudally from approximately the level of the habenula to the rostral border of the posterior corpora quadrigemina. Neurons responding to visual stimulation are generally contained within zones 7b-13, i.e., the superficial 600--700 micrometer of the optic tectum (stratum fibrosum et griseum superficiale and the superficial sublayer of stratum griesum centrale). The infrared cell group is found in layer 7 (a and b; stratum griseum centrale) throughout the optic tectum. Eighty percent of the infrared neurons are found within 500--1,200 micrometer of the surface. In layer 7b the visual and infrared cell groups are mixed; bimodal neurons that respond to a combination of visual and infrared input are located predominantly in this sublamina. The lamination pattern for visual and nonvisual cell groups in the rattlesnake tectum appears to more closely resemble the colubrid tectum and mammalian superior colliculus than the tecta of other reptiles.

GABA immuno-electron microscopic study of the nucleus of the optic tract in the rabbit.

The pretectal nucleus of the optic tract (NOT) was investigated immunocytochemically with an antiserum against gamma aminobutyric acid (GABA) employing the pre-embedding peroxidase antiperoxidase technique at the light microscopic level and the postembedding colloidal gold technique at the electron microscopic level. GABA immunoreactivity was observed in cell bodies of different sizes and as punctate structures in the neuropil. In the electron microscope, besides immunoreactive dendrites, four different types of terminals were found to be GABA-immunopositive; three types of terminals with clustered and flattened vesicles (F-profile) and a fourth type with pleomorphic vesicles, presumably of dendritic origin (P-profile). Both P- and F-profiles formed symmetrical synapses with dendritic profiles arranged in clusters ensheathed by glial elements. GABA-immunopositive terminals were observed in synaptic contact with somata and retinal terminals (R-profiles) that were always GABA-immunonegative. Some GABA-immunopositive somata showed presynaptic contacts with dendrites. The presence of GABA in numerous distinct elements in the NOT and the diversity in labeled somata and terminals demonstrate the importance of the inhibitor neurotransmitter in the NOT and suggest that its function is not limited to interneurons.

Distribution of substance P-like immunoreactive retinal ganglion cells and their pattern of termination in the optic tectum of chick (Gallus gallus).

Substance P-like immunoreactive (SP-LI) neurons were identified within the inner nuclear layer and ganglion cell layer of the chick retina. The SP-LI cells in the inner nuclear layer consisted of several subtypes of neurons, differing in soma size and dendritic arborization. In the ganglion cell layer a population of moderately labelled SP-LI neurons was also present. About 6-9 microns in diameter and spaced 50-80 microns apart, they formed a regular array across the entire retina, with a density of about 400 cells/mm2 in the superior temporal retina, declining to less than 100 cells/mm2 in the peripheral retina. The total number of SP-LI cells in the ganglion cell layer was approximately 75,000. Individual axons could be followed toward the optic nerve head. Lesions near the optic nerve head resulted in axotomy of ganglion cells within a limited portion of the retina. Two days of postaxotomy there were numerous SP-LI swellings in the proximal segments of axotomized axons. SP-LI neurons in the axotomized zone were larger, more numerous, and showed increased staining of their processes. Fourteen days following a retinal lesion, there was depletion of all SP-LI cells in the ganglion cell layer within the axotomized zone, but the SP-LI neurons in the inner nuclear layer were not noticeably affected. Following a localized injection of rhodamine-coupled latex beads into the optic tectum, a population of retinal ganglion cells (RGCs) in the contralateral retina was retrogradely labelled. Many of these cells also exhibited SP-like immunoreactivity. Examination of the optic tectum indicated the presence of SP-LI fibres in laminae 2-13 (nomenclature of Cajal: Histologie du Systeme Nerveux. Vol. 2. Paris: Maloine, '11), with immunoreactive terminal regions present mainly in laminae 2-4, 7, and 9-13. SP-LI cell bodies were found predominantly in laminae 10-12 and 13. Fourteen days following a retinal lesion, SP-LI processes and terminals were depleted from laminae 2 and 3. Immunoreactive cells and processes in the remaining laminae of the optic tectum were not noticeably altered. The present report confirms the existence of SP-LI retinal ganglion cells in the chick retina and demonstrates their contribution to lamina specific SP-LI arborization in the optic tectum.

Time course and pattern of optic fiber regeneration following tectal lobe removal in the goldfish.

Following single tectal lobe removal in the adult goldfish, Carassius auratus, the pattern of regeneration of the optic fibers which had previously projected to that tectum was examined at 1, 2, 4, 6, 8, 10, and 12 weeks postoperative using 3H-proline radioautography. We found that regenerating optic fibers grew across the midline through the transverse, minor, horizontal, and posterior commissures to innervate the remaining tectum. At early postoperative times innervation of the tectum was continuous, while later, the regenerating fibers segregated into discrete patches in the superficial layers of the tectum. In addition, regenerating fibers also grew into non-optic centers/pathways such as the habenula, the fasciculus retroflexus, the forebrain, the torus semicircularis, the valvula and corpus cerebelli, the hypothalamus, and the medulla. While optic fibers were no longer apparent in the habenula and the fasciculus retroflexus after 2 weeks postoperative, all other structures were still occupied by the fibers at 12 weeks postoperative. Since most of the innervated pathways were either tectal efferent pathways, which should contain degenerating debris and proliferating glial cells after the tectal removal, or pathways closely associated with traumatized areas, we suggest that degenerating axonal debris and proliferating glia may play an important role in guiding regenerating fibers in this system.

Catecholaminergic subpopulation of retinal displaced ganglion cells projects to the accessory optic nucleus in the pigeon (Columba livia).

In birds, displaced ganglion cells (DGCs) constitute the exclusive source of retinal input to the nucleus of the basal optic root (nBOR) of the accessory optic system. Tyrosine-hydroxylase (TH) immunoreactivity was examined in the pigeon retina after injections of rhodamine-labeled microspheres into the nBOR. A population of about 400 DGCs was observed in each case to exhibit both TH immunoreactivity and rhodamine bead fluorescence. This corresponded to about 10-15% of the total number of identified DGCs in each retina. Double-labeled cells were medium- to large-size (12 to 20 microns in the largest axis) and were always located at the border between the inner nuclear and the inner plexiform layers. Their dendrites could be followed horizontally in lamina 1 of the inner plexiform layer for up to 300 microns from the cell body. The distribution of double-labeled DGCs appeared to be mostly peripheral, matching the overall distribution of identified DGCs. Larger DGCs (21-28 microns) were never seen to contain TH immunoreactivity. Examination of brain sections revealed plexuses of thin varicose TH-positive axons in all subdivisions of the nBOR. Unilateral enucleation produced an almost complete elimination of TH immunoreactivity in the contralateral nucleus. Such results suggest the existence of a population of catecholaminergic DGCs projecting into the accessory optic system of the pigeon. They also support the emerging hypothesis concerning the neurotransmitter heterogeneity of ganglion cells in the vertebrate retina.

Noradrenergic and serotoninergic innervation of cortical, thalamic, and tectal visual structures in Old and New World monkeys.

Antisera directed against human dopamine-beta-hydroxylase and against serotonin were used to characterize the noradrenergic (NA) and serotoninergic (5-HT) innervation of several cortical and subcortical visual areas in squirrel monkey (Saimiri sciureus) and cynomolgus monkey (Macaca fascicularis). Few species differences were observed for either monoamine. Cortical areas 17 and 18, as well as visual areas in the temporal and parietal lobe were found to exhibit regional specialization of both 5-HT and NA innervation. Precisely at the border between areas 17 and 18, the laminar innervation patterns and density characteristic of NA fibers in area 17 (Morrison et al., '82a; Kosofsky et al., '84) shift so that layer IV of area 18 contains more fibers than layer IV of area 17, and the overall density of fibers in area 18 is higher. For 5-HT, the highly laminated patterns characteristic of area 17 (Morrison et al., '82a; Kosofsky et al., '84) also observe this cytoarchitectonic boundary. Fibers in area 18 are more evenly distributed across laminae, and the overall density of fibers decreases. The visual region of the inferotemporal cortex was found to be very lightly innervated by NA fibers and very densely innervated by 5-HT fibers. Area 7 of the parietal lobule was more densely innervated by NA fibers, and less densely innervated by 5-HT fibers, than any other visual cortical region examined. The visual thalamic nuclei exhibited even greater regional differences in the density of NA innervation. The lateral geniculate nucleus was found to be virtually devoid of NA fibers, while the pulvinar-lateral posterior complex was densely innervated. The density of 5-HT fibers was more uniform across thalamic visual nuclei. The lateral geniculate, pulvinar, and lateral posterior nuclei all exhibit a moderate to high density of immunoreactive fibers. In the mesencephalon, the superficial layers of the superior colliculus were found to be densely innervated by NA fibers, whereas 5-HT fibers were most dense in the intermediate layers. These patterns of innervation indicate that, in these primate species, functionally related visual regions share common and distinguishable densities of NA innervation. Specifically, tecto-pulvinar-juxtastriate structures are more densely innervated than geniculo-striate and inferotemporal structures. These relationships suggest that, within the visual system, NA fibers preferentially innervate the regions involved in spatial analysis and visuomotor response rather than those involved in feature extraction and pattern analysis.(ABSTRACT TRUNCATED AT 400 WORDS)

Age-related changes of catecholamines and their metabolites content in the visual system of the rat.

The changes in the content of the catecholamines in each structure of the geniculate and extrageniculate visual system of the rat during the aging period (6-30 months) have been studied. Dopamine was found at lower levels than noradrenaline in all the structures. The dopamine and noradrenaline showed different developmental profiles. Dopamine and its metabolite levels decreased in the lateral geniculate and visual cortex and increased in superior colliculus and posterior thalamus. Noradrenaline and its metabolites increased in all structures during the aging period. However, 3-methoxy-4-hydroxyphenylglycol/noradrenaline and normetanephrine/noradrenaline ratios decreased in all structures except in superior colliculus. These results suggest age-related changes in the catecholamines in the visual system of the rat.

The brain ganglioside pattern in presenile and senile dementia.

Ganglioside lipid fractions in the cerebral gray matter were studied in 13 patients with various forms of dementia. In 2 patients with Alzheimer's disease and 1 with senile dementia an abnormal ganglioside pattern was observed, i.e., a decrease of G1 and G3 in association with an increase of G2. In the light of the total clinical and histologic data on the patients, it would seem that this disturbance in ganglioside metabolism may be a phenomenon accompanying extensive degradation of brain tissue rather than a factor in the etiology of dementia.

Gas chromatographic method for the determination of trace amounts of putative amino acid neurotransmitters from brain perfusates collected in vivo.

Glass capillary gas chromatography in combination with thermionic detection has been developed for the measurement of trace amounts of glycine, beta-alanine, aspartic acid, gamma-aminobutyric acid and glutamic acid from brain perfusates collected in vivo by push-pull cannula techniques. Amino acids extracted from the dried perfusate residues are converted to the corresponding N-pentafluoropropionyl hexafluoroisopropyl esters (PFP-HFIP derivatives) and separated by gas chromatography on a glass capillary column coated with methylsiloxane. The detection limit of the amino acids (signal-to-noise ratio 3:1) ranges between 200 fmol and 2.0 pmol. The assay was applied to the measurement of amino acids released in vivo in the pigeon optic tectum into perfusates collected by push-pull techniques.

Fast axonal transport in the visual pathway of the chick and rat.

Young chickens and rats were injected intravitreally with [3H]proline and sacrificed at short intervals thereafter. Regression lines calculated for the plotted points (survival time, transport distance) revealed a transport rate of 329 mm/day in the chick and 350 mm/day in the rat. Both rates are close to those reported for peripheral axons (410 +/- 50 mm/day).

Localization of a developmentally regulated neuron-specific protein S54 in dendrites as revealed by immunoelectron microscopy.

We sought to determine the ultrastructural localization of the developmentally regulated neuron-specific protein S54 in the chicken cerebellar cortex and optic tectum. The brains were fixed by perfusion with paraformaldehyde and glutaraldehyde. Frozen sections were immunocytochemically labeled with a monoclonal antibody to S54 protein. The immunoreactivity for S54 protein was localized in dendrites. No immunoreactivity for S54 protein was detected in axons and their presynaptic terminals.

Immunocytochemical analysis of proenkephalin-derived peptides in the amphibian hypothalamus and optic tectum.

[Met5]-Enkephalin-, [Met5]-enkephalin-Arg6-, [Met5]-enkephalin-Arg6-Phe7-, metorphamide- and BAM 22P-like peptides could be localized in the amphibian brain by immunocytochemistry. However, a [Met5]-enkephalin-Arg6-Gly7-Leu8-like peptide could not be detected in the brain of any anuran species with an antiserum that was capable of detecting this octapeptide in mammalian brain. A synenkephalin-like peptide also could not be detected in the anuran brain with an antiserum that was capable of detecting the antigen in bovine and porcine brain. Although the intensity of proenkephalin-like immunoreactivity depended on the antiserum used, its distribution appeared to be identical with all of the effective antisera. Antisera directed against somatostatin and corticotropin-releasing factor stained perikarya, nerve fibers and terminals in the anuran brain with a distribution that was different from antisera directed against proenkephalin-derived peptides. The distribution of proenkephalin-containing perikarya and nerve fibers in the regions of the anuran brain selected for study showed many similarities to the distribution of proenkephalin-containing perikarya and nerve fibers in the same regions of the amniote brain.

Isolation of axonally transported glycoproteins with goldfish visual system myelin.

[3H]fucose labeled glycoproteins which are rapidly transported in the goldfish optic nerve have been isolated with purified preparations of goldfish optic tectal myelin. SDS acrylamide gels of myelin proteins isolated one day after intraocular injection of fucose show a broad distribution of radioactivity among high molecular weight proteins. At progressively longer times after injection there is a shift in the distribution of radioactivity with the buildup of a peak of label with electrophoretic mobility corresponding to a molecular weight of approximately 50,000. There is no corresponding peak of radioactivity in gels of total tectal membranes. Gels of myelin labeled through intracranial injections of fucose also show no single prominent peak of radioactivity. Results are discussed with reference to possible mechanisms for the shift in radioactivity patterns on gels and the possible functional significance of the myelin-associated glycoproteins.

Benzodiazepine receptors in the visual structures of monocularly deprived rats. Effect of light and dark adaptation.

In 25-day-old rats with one eyelid sutured at the age of 10 days, the binding of [3H]flunitrazepam in the visual structures (retina, lateral geniculate nucleus, superior colliculus, visual cortex) and frontal cortex was determined. Monocular visual deprivation (MD) resulted in a significant decrease of the [3H]flunitrazepam binding in the retina of the open eye to about 76% of the control value. No changes in [3H]flunitrazepam binding were detectable under these conditions in the central visual structures examined and the non-visual cortical region. Scatchard analysis indicated that the changes found in the retina of the open eye of MD rats are due to a decreased binding affinity only, the maximum receptor number being unaffected. Eight hours after re-opening the sutured eyelid of 25-day-old MD rats, benzodiazepine binding in the open eye was increased to the control level, whereas the binding in the retina of the re-opened eye remained unchanged in comparison to control animals. Dark adaptation of 25-day-old control rats resulted in an increased [3H]flunitrazepam binding in the retina by 28% compared to that detectable in the retina of light-adapted animals. In contrast, dark-adaptation of MD rats did not affect [3H]flunitrazepam binding in the retina of both eyes in comparison to that found in the corresponding retina of light-adapted MD animals. The data obtained suggest a physiological coupling between both retinas, possibly mediated through centres inside of the central nervous system.

N-acetylaspartylglutamate identified in the rat retinal ganglion cells and their projections in the brain.

N-Acetylaspartylglutamate like immunoreactivity (NAAG-L) was identified in retinal ganglion cell bodies and their axons. The presence of the dipeptide in ganglion cell projection areas, the lateral geniculate nucleus (LGN) and superior colliculus (SC), was confirmed following NAAG purification from these tissues by a high-performance liquid chromatographic method. NAAG-L was identified in the optic tract as well as within fibers and puncta in the LGN and SC. The hypothesis that NAAG is present within ganglion cell axons in the brain was tested by unilateral enucleation which resulted in loss of NAAG and NAAG-L within the contralateral LGN and SC.

N-acetylaspartylglutamate immunoreactivity in neurons of the cat's visual system.

The acidic dipeptide, N-acetylaspartylglutamate (NAAG) was identified immunohistochemically within neurons of the cat's visual system. In the retina, NAAG-like immunoreactivity was observed in some horizontal and amacrine cells at the inner and outer margins of the bipolar cell layer. NAAG-like immunoreactivity was also observed in many retinal ganglion cell bodies, their neurites, and the neuropil of their target areas, the lateral geniculate nucleus (LGN) and the superior colliculus. Additionally, peptide immunoreactivity was also seen in the projection neurons of the LGN, in cells of the pulvinar nucleus, and in the pyramidal cells of layers III and V in areas 17, 18 and 19 of the cerebral cortex. These data suggest that NAAG or a structurally related molecule may have a prominent role in the communication of visual signals at retinal, thalamic and cortical levels.