Neuronal Recognition

An outstanding characteristic of the nervous system is that neurons make selective functional contacts. Each neuron behaves as if it recog­ nizes the neurons with which it associates and rejects associations with others. The specific interneuronal relationships that result define the innate neuronal circuits that determine the functioning of this system. The purpose of this volume is to present some approaches to the problem of neuronal recognition. The volume has been somewhat arbitrarily divided into three sections. In the first section, the overrid­ ing theme is the degree of specificity of neuronal recognition. How specific is specific? Is the specificity so precise that the neurites of one neuron will only make synaptic contact with a unique target neuron? If less precise, within what range? Are the rules for specification that are operative in the embryo still operative at the same level of precision when connections regenerate in the mature organism? Are they still operative in dissociated tissue grown in culture? The second section of this volume contains reviews of morphologi­ cal studies of synaptogenesis and biochemical studies of synaptic com­ ponents. Can the morphology of developing cellular contacts provide clues about selectivity? Can the chemical components of synaptic junc­ tions be isolated and characterized? Do they include resolvable compo­ nents that mediate neuronal recognition? The third section contains studies seeking to identify the existence of specific molecules that might mediate cellular recognition. A major question here is whether molecules of this type even exist.

Contenu

I. Specificity in Synaptic Development and Regeneration.- 1. Neuronal Recognition in the Retinotectal System.- 1. Introduction.- 2. Alternatives to Neuronal Recognition.- 3. Development of Specific Properties in Neuronal Sets.- 4. Targeting of the Retinal Axons onto Tectal Neurons.- 5. References.- 2. Specificity of Nerve-Muscle Interactions.- 1. Introduction.- 2. Normal Adult Neuromuscular Connections.- 2.1. Structure of Neuromuscular Junctions.- 2.2. Stability of Neuromuscular Junctions.- 2.3. Inferences About Neuromuscular Interactions.- 3. Development of Neuromuscular Connections.- 3.1. Development of Skeletal Muscle.- 3.2. Development of Motoneurons.- 3.3. Neuromuscular Interactions During Synapse Formation.- 3.4. Inferences about Nerve-Muscle Specificity Based on Developmental Studies.- 4. Innervation of Skeletal Muscles by Their Own and Foreign Nerves.- 4.1. Locus of Reinnervation.- 4.2. Specificity of Innervation of Muscle Fibers During Reinnervation.- 4.3. Inferences about Nerve-Muscle Specificity Based on Reinnervation Experiments.- 5. References.- 3. Reactive Synaptogenesis in the Adult Nervous System: The Effects of Partial Deafferentation on New Synapse Formation.- 1. Introduction.- 2. General Properties of Reactive Synaptogenesis.- 3. Characteristics of Reinnervation in the Dentate Gyrus.- 4. Mechanisms of Reactive Synaptogenesis: The Dentate Gyms as a Model System.- 4.1. Initiation.- 4.2. Control of Growth Rate.- 4.3. Synaptic Junction Formation.- 4.4. Specification of Synaptic Fields.- 4.5. Summary.- 5. Developmental Differences in Reactive Synaptogene sis.- 6. Significance of Reinnervation in the Central Nervous System.- 7. References.- 4. The Expression of Neuronal Specificity in Tissue Culture.- 1. Introduction.- 2. Observations on Cultures of the Central Nervous System.- 3. Observations on Neuromuscular Junctions and Dissociated Sensory Neurons.- 4. Observations on Synapses Between Spinal Cord and Autonomic Neurons in Culture.- 4.1. Explant Cultures.- 4.2. Synapses Formed Between Spinal Cord Explants and Dissociated Neurons of the Rat Superior Cervical Ganglion.- 5. Observations on Connectivity Between Isolated Autonomic Neurons.- 6. Summary and Conclusions.- 7. References.- II. Morphological and Biochemical Studies of Synapses.- 5. From the Growth Cone to the Synapse: Properties of Membranes Involved in Synapse Formation.- 1. Introduction.- 2. The Membrane Surface at the Synaptic Site..- 2.1. Synaptic Cleft Morphology.- 2.2. Synaptic Cleft Cytochemistry.- 2.3. Synaptic Adhesion Mechanism.- 2.4. Inner Structure of Synaptic Membranes.- 3. The Nerve Growth Cone and Some of Its Membrane Properties.- 3.1. Growth Cone Morphology.- 3.2. Intrinsic Structure of the Growth Cone Membrane.- 3.3. Growth Cone Membrane Cytochemistry.- 4. The Formation of the Synaptic Junction.- 4.1. Initial Encounter of Synaptic Partners.- 4.2. Postsynaptic Response.- 4.3. Changes in the Intercellular Space.- 4.4. Presynaptic Developments.- 4.5. Five Steps of Synapse Formation.- 5. Discussion: The Specific Nature of the Recognizing Membrane.- 6. References.- 6. Biochemical Studies of Synaptic Macromolecules: Are There Specific Synaptic Components?.- 1. Introduction.- 2. Isolation of Neural Plasma Membranes.- 3. Chemical Composition of Neural Plasma Membranes.- 3.1. Proteins.- 3.2. Glycoproteins.- 3.3. Gangliosides.- 3.4. Mucopolysaccharides.- 4. Enzyme Localization in Neural Plasma Membranes.- 5. Immunological Studies of Neural Plasma Membranes.- 6. Conclusions.- 7. References.- III. Toward a Molecular Basis of Neuronal Recognition.- 7. Cell Recognition in Embryonic Morphogenesis and the Problem of Neuronal Specificities.- 1. Introduction.- 2. Cell Aggregation.- 3. Tissue-Specific Cell Recognition.- 4. Specific Cell-Aggregating Factors.- 5. Purification of the Retina Cell-Aggregating Factor.- 6. The Cell-Ligand Hypothesis.- 7. References.- 8. An in Vitro Assay for Retinotectal Specificity.- 1. Introduction: Specific Adhesion as a Morphogenetic Mechanism.- 1.1. Holtfreter and Selective Affinities.- 1.2. Weiss and Molecular Complementarity.- 1.3. Sperry and Neuronal Specificity.- 2. Assays for Adhesive Specificity.- 2.1. Sorting Out.- 2.2. Collecting-Aggregate Assay.- 2.3 Variations of the Collection Assay.- 2.4. Conclusion.- 3. Adhesive Measurements in the Retinotectal System.- 3.1. The Assay and Results.- 3.2. Changes with Development.- 3.3. Which Retinal Cells Are Adhering?.- 3.4. The Tectal Surface.- 3.5. Magnitude of the Adhesive Selectivity.- 3.6. Biochemical Approaches.- 3.7. Conclusions.- 4. Summary.- 5. References.- 9. Membranes as a Tool for the Study of Cell Surface Recognition.- 1. Introduction.- 2. Techniques.- 3. Organ Specificity.- 4. Temporal Specificity.- 5. Solubilization of Aggregation Inhibitory Factors.- 6. Trophic Effect of Nerve Growth Factor on Temporal Differentiation.- 7. Summary.- 8. References.- 10. Morphogenetic Role of Glycosaminoglycans (Acid Mucopolysaccharides) in Brain and Other Tissues.- 1. Introduction.- 2. Glycosaminoglycans and Proteoglycans.- 2.1. Structure.- 2.2. Properties.- 2.3. Metabolism.- 3. Morphogenetic Role of Hyaluronate.- 3.1. Correlation of Hyaluronate Synthesis and Hyaluronidase Activity with Morphogenetic Events in Vivo.- 3.2. Influence of Hyaluronate on Cells in Vitro.- 3.3. Thyroxine Antagonism of the Action of Hyaluronate.- 4. Morphogenetic Role of Sulfated Proteoglycans.- 5. Hyaluronate and Brain Morphogenesis.- 6. References.- 11. Cell Surface Carbohydrate-Binding Proteins: Role in Cell Recognition.- 1. Introduction.- 2. Advantages of Cellular Slime Molds for Studies of Cell Recognition.- 3. Developmentally Regulated Carbohydrate-Binding Proteins in Cellular Slime Molds.- 3.1. Parallel Appearance of Carbohydrate-Binding Proteins and Cohesiveness.- 3.2. Purification of Discoidin and Pallidin.- 4. Cell Surface Location of Discoidin and Pallidin.- 5. Developmental Regulation of Cell Surface Receptors for Discoidin and Pallidin.- 6. Blocking of Slime Mold Cohesion by Specific Sugars.- 7. Specificity of Carbohydrate-Binding Proteins from Other Species of Cellular Slime Molds.- 8. Species Specificity of Cell Surface Receptors on P. pallidum and D. discoideum.- 9. Evidence for Cell Surface Protein-Carbohydrate Interactions in Other Systems.- 10. Implications for Neuronal Recognition.- 11. Referen…