The alpha-2 Adrenergic Receptors

Ions.- 5.3. Divalent Cations Regulate Adenylate Cyclase at Several Sites.- 5.4. Inhibitory Coupling of alpha-2 Adrenergic Receptors Is Highly Susceptible to Alkylation by N-Ethylmaleimide.- 5.5. alpha-2 Adrenergic Inhibition of Adenylate Cyclase Can Be Specifically Blocked by Limited Proteolysis.- 5.6. Protein Kinase C Interferes with alpha-2 Adrenergic Inhibition of Adenylate Cyclase in Human Platelet Membranes.- 6. Conclusion.- References.- Section 4: Correlation of Receptor Binding and Function.- 4 Structure-Activity Relationships for alpha-2 Adrenergic Receptor Agonists and Antagonists.- 1. Introduction.- 2. alpha-Adrenergic Receptor Subclassification.- 2.1. Methods of Subclassification.- 2.2. alpha-2 Adrenergic Receptor Heterogeneity.- 2.3. Postsynaptic vs Presynaptic alpha-2 Adrenergic Receptors.- 3. Structure-Activity Relationships of alpha-2 Adrenergic Receptors.- 3.1. Stereochemical Requirements of alpha-2 Adrenergic Receptors.- 3.2. Structure-Activity Relationships of the alpha-2 Adrenergic Receptor for the Phenethylamines.- 3.3. Structure-Activity Relationships of the alpha-2 Adrenergic Receptor for the Imidazolines.- 3.4. Structure-Activity Relationships of the alpha-2 Adrenergic Receptor for Antagonists.- 3.5. Model of the alpha-2 Adrenergic Receptor Based on the Structural Requirements for alpha-2 Adrenergic Receptor Antagonists.- 4. Summary and Conclusions.- References.- 5 Functions Mediated by alpha-2 Adrenergic Receptors.- 1. Introduction.- 2. alpha-2 Adrenergic Receptors in the Cardiovascular System.- 2.1. Cardiovascular Effects Mediated by Central alpha-2 Adrenergic Receptors.- 2.2. Peripheral Arterial alpha-2 Adrenergic Receptors.- 2.3. Peripheral Venous Circulation.- 2.4. Myocardium.- 2.5. alpha-2 Adrenergic Receptors in the Kidney.- 3. Functions Mediated by alpha-2 Adrenergic Receptors in Various Noncardiovascular Tissues.- 3.1. Inhibition of Neurotransmitter Release.- 3.2. Functional Role of Platelet alpha-2 Adrenergic Receptors.- 3.3. Sedation Mediated by alpha-2 Adrenergic Receptors.- 3.4. Interaction of alpha-2 Adrenergic Receptors and Opiate Receptors in the Central Nervous System.- 3.5. Suppression of Insulin Release by alpha-2 Adrenergic Receptors.- 3.6. alpha-2 Adrenergic Receptors in the Gastrointestinal Tract.- 3.7. alpha-2 Adrenergic Receptors in Uterus.- 4. Correlation Between alpha-2 Adrenergic Receptor Occupancy (Binding) and Function.- 4.1. Occupancy-Response Relationships.- 4.2. Second Messengers.- 5. Comparison of Drug Potencies in Biochemical and Physiologic Assay Systems for alpha-2 Adrenergic Receptors.- 6. Summary and Conclusions.- References.- Section 5: Receptor Regulation.- 6 Regulation of alpha-2 Adrenergic Receptors.- 1. Introduction.- 2. Physiologic Regulation of alpha-2 Adrenergic Receptors.- 2.1. Developmental Changes in alpha-2 Adrenergic Receptors.- 2.2. alpha-2 Adrenergic Receptors in States of Altered Nutritional Status.- 2.3. Changes in alpha-2 Adrenergic Receptors with Exercise.- 2.4. alpha-2 Adrenergic Receptors in the Menstrual (Estrus) Cycle and Pregnancy.- 3. Pharmacologic Regulation of alpha-2 Adrenergic Receptors.- 3.1. Homologous Regulation of alpha-2 Adrenergic Receptors.- 3.2. Heterologous Regulation of alpha-2 Adrenergic Receptors.- 4. Disease-Related Changes in alpha-2 Adrenergic Receptors.- 4.1. Cardiovascular Diseases.- 4.2. Platelet Disorders.- 4.3. Psychiatric Disorders.- 4.4. Miscellaneous Diseases.- 5. Summary and Conclusions.- References.- Section 6: Future Vistas.- 7 What Happens Next? A Hypothesis Linking the Biochemical and Electrophysiological Sequelae of alpha-2 Adrenergic Receptor Occupancy with the Diverse Receptor-Mediated Physiological Effects.- 1. Introduction.- 2. Biochemical Consequences of alpha-2 Adrenergic Receptor Occupancy in Addition to the Inhibition of Adenylate (Cyclase.- 2.1. alpha-2 Adrenergic Receptors and Na+/H+ Exchange.- 2.2. alpha-2 Adrenergic Receptors and Ca2+.- 3. Electrophysiological Consequences of alpha-2 Adrenergic Receptor Occupancy.- 3.1. alpha-2 Adrenergic Receptors and K+ Conductance.- 3.2. alpha-2 Adrenergic Receptors and Ca2+ Conductance.- 3.3. GTP-Binding Proteins Are Involved in alpha-2 Adrenergic Receptor-Mediated Modulation of Ion Channels.- 4. Hypothesis: Na+/H+ Exchange, Changes in Ca2+ Availability and Ion Channel Conductances Interact to Elicit alpha-2 Adrenergic Receptor-Mediated Physiological Effects.- 5. Summary and Future Perspectives.- References.