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Chapter 12. Basic Principles of Neuropharmacology. Basic Principles of Neuropharmacology. Neuropharmacology can be defined as “the study of drugs that alter processes controlled by the nervous system.”
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Chapter 12 Basic Principles of Neuropharmacology
Basic Principles of Neuropharmacology • Neuropharmacology can be defined as “the study of drugs that alter processes controlled by the nervous system.” • These drugs are used to treat conditions ranging from depression to epilepsy to hypertension to asthma.
Basic Principles of Neuropharmacology • How neurons regulate physiologic processes • Basic mechanisms by which neuropharmacologic agents act: • Sites of action: axons vs. synapses • Steps in synaptic transmission • Effects of drugs on the steps of synaptic transmission
Fig. 12-1. How neurons regulate other cells. There are two basic steps in the process by which neurons elicit responses from other cells: (1) axonal conduction and (2) synaptic transmission. (T = neurotransmitter.)
Basic Mechanisms of Neuropharmacologic Agents • Sites of action: axons vs. synapses • Axonal conduction • Synaptic transmission • Receptors
How Neurons Regulate Physiologic Processes in Two Basic Steps • Axonal conduction • Action potential down the axon • Synaptic transmission • Information carried across the neuron gap and the postsynaptic cell • Postsynaptic cell • Another neuron, muscle cell, or cell within a secretory gland
Basic Mechanisms of Neuropharmacologic Agents • Effects of drugs on the steps of synaptic transmission • Transmitter synthesis • Increase transmitter synthesis • Decrease transmitter synthesis • Cause synthesis of transmitter molecules • Transmitter storage • Cause receptor activation to decrease • Transmitter release • Promote or inhibit release
Basic Mechanisms of Neuropharmacologic Agents • Effects of drugs on the steps of synaptic transmission • Receptor binding • Cause activation • Block activation • Enhance activation • Termination of transmission • Block transmitter reuptake • Inhibit transmitter degradation
Multiple Receptor Types and Selectivity of Drug Action • Selectivity • Most desirable quality a drug can have • Able to alter a disease process while leaving other physiologic processes largely unaffected
Meet Mort and Merv Fig. 12-3. Multiple drug receptors and selective drug action.
An Approach to Learning About Peripheral Nervous System Drugs • Three types of information needed • Type (or types) of receptor through which the drug acts (alpha1, alpha2, beta1, etc) • Normal response to activation of those receptors (agonist versus antagonist) • What the drug in question does to receptor function
Basic Principles of Neuropharmacology • An approach to learning about peripheral nervous system drugs • Knowing the receptors that the drug affects • Knowing the normal responses to activation of those receptors • Knowing whether the drug in question increases or decreases receptor activation