1 Peptides in Neurobiology: Historical Introduction.- 1. The Neurosecretory Neuron and the Concept of Neurosecretion.- 2. The Hypothalamic Origin of the Posterior Lobe Hormones.- 3. The Hypothalamic Control of the Adenohypophysis.- 4. Nonhormonal Neurosecretory Signals to Endocrine and Nonendocrine Effector Cells.- 5. Peptidergic Interneuronal Communication.- 6. Conclusion.- 7. References.- 2 Application of Fluorescent Techniques to the Study of Peptides.- 1. Introduction.- 2. Preparation of Materials and Equipment.- 3. Isolation of Peptides from Tissues.- 4. Separation and Detection of Peptides.- 4.1. Noncolumn Methods for Free Peptides.- 4.2. Column Methods for Free Peptides.- 4.3. Noncolumn Methods for Prelabeled Peptides.- 4.4. Column Methods for Prelabeled Peptides.- 5. Applications.- 5.1. Isolation of Pure Peptides.- 5.2. Quantitative Analysis.- 5.3. Physiological Studies.- 5.4. Chemical Characterization.- 6. Conclusion.- 7. References.- 3 Specific Problems in the Identification and Quantitation of Neuropeptides by Radioimmunoassay.- 1. Introduction.- 2. Radioimmunoassay for Detection of Well-Characterized Peptides in Nervous Tissues.- 2.1. Species-Specificity.- 2.2. Preparation of Tissue Extracts.- 2.3. Sources of Artifact.- 2.4. PhysicalChemical Characterization.- 3. Development of Radioimmunoassay Systems for Newly Described Peptides.- 3.1. Production of Antisera.- 3.2. Labeled Peptide.- 3.3. Preparation of Standards.- 3.4. Separation Techniques.- 4. Conclusions and Conjectures.- 5. References.- 4 Immunocytochemistry of Neuropeptides and Their Receptors.- 1. Introduction.- 2. The Unlabeled Antibody Enzyme MethodSensitivity of Immunocytochemistry.- 3. Modifications of the Unlabeled Antibody Enzyme Method.- 4. Immunocytochemical Staining of Nervous Tissue.- 5. Neurotransmitter PathwaysCatecholamines and Serotonin.- 6. Hypothalamopituitary Pathways.- 6.1. Oxytocin, Vasopressin, and Angiotensin.- 6.2. Luteinizing HormoneReleasing Hormone, Somatostatin, and lc+