central nervous system (CNS)

peripheral nervous system (PNS)

    somatic nervous system

    autonomic nervous system (ANS)

        sympathetic division

        parasympathetic division

brain areas to be familiar with to understand drug effects:

    Brain stem (medulla, pons, midbrain)

    reticular formation or reticular activating system

    cerebellum

    thalamus

    hypothalamus

    limbic system (hypothalamus, amygdala, hippocampus)

        medial forebrain bundle (MFB)

        ventral tegmental area (VTA)

        nucleus accumbens

    basal ganglia/extrapyramidal motor system

    cortex (cerebrum)

neuron or nerve cell

    dendrites

    cell body or soma

    axon

        axon terminals

nerve impulse

synapse

    chemical transmission

    synaptics vesicles

    synaptic cleft or gap

    neurotransmitters

    receptors or receptor sites or receptor proteins

    presynaptic membrane (axon)

    postsynaptic membrane (dendrite)

normal chemical processes in neurons (synthesis of transmitter, storage of transmitter, release of transmitter)

ways of cleaning up released neurotransmitter

    reuptake

    enzymatic breakdown
 

Note: although you must become familiar with these neurotransmitters, p. 42-50 has more detail than we need now. Use lecture and our Neurotransmitter handout to study.

best known transmitters

    acetylcholine (ACh)

    norepinephrine (NE)

    dopamine (DA)

    serotonin (5HT)

    gamma-amino-butyric acid (GABA)

    glutamate

    endorphins or opioid peptides

    Others we'll come across: endorphins, enkephalins, adenosine, histamine, Substance P, anandamide

multiple types of receptors for each neurotransmitter (e.g. at least 6 different kinds of DA receptors)
    located in different regions of brain

examples of drug actions on neurotransmitters

pharmacodynamics (drug actions) (p. 23-29)

    receptors or receptor proteins

    drug-receptor interactions or drug-receptor binding

    receptor specificity

    natural, endogenous ligand/neurotransmitter fitting receptor

    multiple receptor types for a particular neurotransmitter

    drug similarities to natural, endogenous neurotransmitter

    General categories of drug actions:

    1) drug can bind to receptor and mimic effect of normal transmitter ("agonistic action")

    2) drug can bind to receptor, facilitating the binding of neurotransmitter (another form of agonistic action)

     3) drug can occupy receptor but trigger no response ("antagonistic or blocking action")

Types of receptors

1) some receptors, when activated, quickly & directly affect the electrical charge of the neuron by opening ion channels

2) some receptors, when activated, triggers a slower complex chain reaction involving a "G-protein" and a second chemical
messenger, which in turn can affect many different cellular functions

3) some receptors function as transporters, moving molecules from one place (e.g. outside of neurons) to another (e.g. inside of neurons)

4) some receptors are on enzymes and, when occupied, affect the functioning of that enzyme
termination of action and elimination (metabolism and excretion)