neuropharmacology and a brief review of physiology

Chapters 12 & 13: 

Chapters 12 & 13 Basic Principles of Neuropharmacology Physiology of the Peripheral Nervous System

Basic Principles of Neuropharmacology: 

Basic Principles of Neuropharmacology How neurons regulate physiologic processes Basic mechanisms by which neuropharmacologic agents act Sites of action: axons versus synapses Steps in synaptic transmission Effects of drugs on the steps of synaptic transmission

Basic Principles of Neuropharmacology: 

Basic Principles of Neuropharmacology Multiple receptor types and selectivity of drug actions 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

Slide 4: 

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.)

Slide 5: 

Fig. 12-2. Steps in synaptic transmission. Step 1, Synthesis of transmitter (T) from precursor molecules (Q, R, and S). Step 2, Storage of transmitter in vesicles. Step 3, Release of transmitter: In response to an action potential, vesicles fuse with the terminal membrane and discharge their contents into the synaptic gap. Step 4, Action at receptor: Transmitter binds (reversibly) to its receptor on the postsynaptic cell, causing a response in that cell. Step 5, Termination of transmission: Transmitter dissociates from its receptor and is then removed from the synaptic gap by (a) reuptake into the nerve terminal, (b) enzymatic degradation, or (c) diffusion away from the gap.

Basic Mechanisms: 

Basic Mechanisms

Basic Mechanisms of Neuropharmacologic Agents: 

Basic Mechanisms of Neuropharmacologic Agents Effects of drugs on the steps of synaptic transmission: Transmitter synthesis Increase transmitter synthesis Decrease transmitter synthesis Cause the synthesis of transmitter molecules Transmitter storage Cause receptor activation to decrease Transmitter release Promote or inhibit release

Basic Mechanisms of Neuropharmacologic Agents: 

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: 

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: 

Meet Mort and Merv Fig. 12-3. Multiple drug receptors and selective drug action. Mort, All of Mort ’ s organs are regulated through activation of type A receptors. Drugs that affect type A receptors on one organ will affect type A receptors on all other organs. Hence, selective drug action is impossible. Merv, Merv has four types of receptors (A, B, C, and D) to regulate his four organs. A drug that acts at one type of receptor will not affect the others. Hence, selective drug action is possible.

An Approach to Learning About Peripheral Nervous System Drugs: 

An Approach to Learning About Peripheral Nervous System Drugs Three types of information needed: Type (or types) of receptor through which the drug acts (alpha 1 , alpha 2 , beta 1 , etc) Normal response to activation of those receptors (agonist versus antagonist) What the drug in question does to receptor function

Slide 12: 

12

Slide 13: 

Fig. 13-1. Opposing effects of parasympathetic and sympathetic nerves.

Receptors of the Peripheral Nervous System: 

Receptors of the Peripheral Nervous System

Classification of Cholinergic and Adrenergic Receptors: 

Classification of Cholinergic and Adrenergic Receptors

Receptors of the Peripheral Nervous System: 

Receptors of the Peripheral Nervous System