Chapter 4A: The Chemistry of Behavior: Neurotransmitters and Neuropharmacology

Question 1

Neurochemistry

Answer 1

Focuses on the basic chemical composition and processes of the nervous system

Question 2

Neuropharmacology

Answer 2

The study of compounds that selectively affect the nervous system

Question 3

Co-localization (co-release)

Answer 3

Some neurons contain more than one type of neurotransmitter

Question 4

Receptor subtypes

Answer 4

Different receptor subtypes may trigger different responses in target cells

Varied outcomes because of these subtypes

Subtypes differ based on what cells they’re on

Question 5

Criteria for neurotransmitters

Answer 5

Substance exists in presynaptic axon terminals

Synthesized in presynaptic cells

Released when action potentials reach axon terminals

Receptors for the substance exist on the postsynaptic membrane

When experimentally applied, substance produces changes in postsynaptic cells

Blocking substance release prevents changes in postsynaptic cell

Question 6

Types of neurotransmitters

Answer 6

Amino acid
Amine
Peptide
Gas

Question 7

Amino acid neurotransmitters

Answer 7

GABA, glutamate

Question 8

Amine neurotransmitters

Answer 8

Acetylcholine, dopamine, serotonin

Question 9

Peptide neurotransmitters

Answer 9

Short-chain amino acids

Question 10

Gas neurotransmitters

Answer 10

Soluble gases, nitric oxide, carbon dioxide

Question 11

Most prevalent excitatory neurotransmitter in the brain

Answer 11

Glutamate

Question 12

Most prevalent inhibitory neurotransmitter in the brain

Answer 12

GABA

Question 13

GABAa

Answer 13

Ionotropic, producing fast, inhibitory effects

Question 14

GABAb

Answer 14

Metabotropic, slow, inhibitory effects

Question 15

GABAc

Answer 15

Ionotropic

Question 16

GABA agonists

Answer 16

Potent tranquilizers
Ex: Valium

Question 17

First neurotransmitter identified

Answer 17

Acetylcholine (ACh)

Two types: nicotinic, muscarinic

Question 18

Cholinergic cells

Answer 18

Release ACh

These cells project to amygdala, hippocampus, and throughout cortex

Important for learning and memory, lost with Alzheimer’s disease

Question 19

Nicotinic ACh receptors

Answer 19

Ionotropic, excitatory, fast

Question 20

Muscarinic ACh receptors

Answer 20

G protein-coupled, slower, and excitatory or inhibitory

Question 21

2 main classes of monoamine neurotransmitters

Answer 21

Catecholamines: dopamine, epinephrine, norepinephrine

Indoleamines: melatonin, serotonin

Question 22

2 main pathways for dopamine

Answer 22

Mesostriatal pathway: motor control

Mesolimbocortical pathway: reward and reinforcement

Question 23

Norepinephrine

Answer 23

Metabotropic

Alertness, mood, sexual behavior

Question 24

Serotonin

Answer 24

Mainly found in raphe nuclei

Sleep, mood, sexual behavior, anxiety

Question 25

Peptides

Answer 25

Act as neurotransmitters or as hormones Some are opioid peptides, which are endogenous substances that resemble opiate drugs

Question 26

Gas

Answer 26

Nitric oxide is a soluble gas neurotransmitter Made in dendrites, diffuses out immediately into cells to stimulate second-messenger systems Retrograde transmitter

Question 27

Agonist

Answer 27

Drug that binds to and activates a specific receptor

Question 28

Antagonist

Answer 28

Binds to the receptor but does not activate it

Question 29

Noncompetitive ligand

Answer 29

Can either activate receptor or block it from being activated

Question 30

How do drugs know where to go?

Answer 30

They find the receptor where they have their action

Question 31

Affinity

Answer 31

The binding affinity is the degree of attraction between a ligand and a receptor A drug with high affinity will be effective at low doses and stay bound for a long time

Question 32

Low-affinity ligands

Answer 32

Neurotransmitters are low-affinity ligands, allowing them to rapidly dissociate from receptors

Question 33

Efficacy

Answer 33

The ability of the bound ligand to activate that receptor Agonists: high efficacy Antagonists: low efficacy Partial agonists: produce a medium response regardless of dose

Question 34

Dose-response curve

Answer 34

Graph of the relationship between drug doses and the effects At some point it levels out and you can’t get more of a response no matter how much more you add

Question 35

Potency

Answer 35

Can be determined by comparing ED50 values (dose at which the drug has 50% of its maximum effect) A drug that has comparable effects at lower doses is more potent You don’t have to give as high of a dose to get that 50% response

Question 36

Therapeutic index

Answer 36

Separation between ED50 and LD50 (dose at which 50% of subjects start to show signs of toxicity) We very rarely approve drugs with narrow therapeutic index because if you forget you take a medication and accidentally take it again then you could die

Question 37

Pharmacokinetics

Answer 37

Factors that affect the movement of a drug into, through, and out of the body

Question 38

Blood-brain barrier

Answer 38

Tight junctions within the CNS that prevent the movement of large molecules Lined with glial cells (astrocytes)

Question 39

Route of administration can affect...

Answer 39

Amount of drug that reaches the brain Speed with which it starts acting Bioavailability: amount of drug free to act on the target tissue

Question 40

Repeated treatments may reduce the effectiveness of a drug

Answer 40

Changes in receptor number on the postsynaptic membrane Increasing: upregulation Decreasing: downregulation Both of these change the way the postsynaptic cell is firing

Question 41

Presynaptic events can be modified by drugs that affect...

Answer 41

Transmitter production Neurotransmitter release Transmitter clearance

Question 42

Drugs can act postsynaptically

Answer 42

Block specific receptors Or change upward or downward regulation