Signal Transduction and the Chemically Addressed Nervous System

• Principles of chemical neurotransmission
• Neurotransmitters, cotransmitters, and natural polypharmacy
• Neurotransmission: classic, retrograde, and volume
• Excitation-secretion coupling
• Signal-transduction cascades
• Overview
• Forming a second messenger
• Beyond the second messenger
• Gene expression
• Summary

Signal Transduction and the Chemically Addressed Nervous System

Neurotransmission has an anatomical infrastructure, but it is fundamentally a very elegant chemical operation. The discussions of the anatomically addressed nervous system and the structural basis of neurotransmission in the previous two chapters (Chapters 1 and 2) set the stage now, in Chapter 3, for describing the chemically addressed nervous system and the molecular basis of neurotransmission. An understanding of the principles of chemical neurotransmission is a fundamental requirement for grasping how psychopharmacological agents work via their actions upon key molecules involved in neurotransmission. Drug targeting of specific chemical sites that influence neurotransmission is discussed in the two chapters that follow (Chapters 4 and 5). An understanding of the chemically addressed nervous system is also a prerequisite for becoming a “neurobiologically informed” clinician, best able to translate exciting new findings on brain circuitry, functional neuroimaging, and genetics into clinical practice and potentially improving the manner in which psychiatric disorders and their symptoms are diagnosed and treated in the modern era. The chemistry of neurotransmission in specific brain regions is discussed in Chapter 6, and then these principles are applied to various specific psychiatric disorders throughout the rest of this book.