The Brain (Kapitel 4)

Question 1

Name the 6 criteria for a substance to be considered a classic neurotransmitter.

Answer 1

• The substance exists in presynaptic axon terminals
• The presynaptic cell contain appropriate enzymes for synthesizing the substance.
• The substance is released in significant quantities when action potentials reach the terminals.
• Specific receptors that recognize the released substance exists on the postsynaptic membrane.
• Experimental application of the substance produces changes in postsynaptic cells.
• Blocking release of the substance prevents presynaptic activity from affecting the postsynaptic cell. (p. 92)

Question 2

Name the types (categories) of neurotransmitters that are often seen in the brain.

Answer 2

Amine Neurotransmitters
Amino acid neurotransmitters
Peptide neurotransmitters (or neuropeptides)
Gas neurotransmitters. (p. 92)

Question 3

Name some Amine Neurotransmitters

Answer 3

Acetylcholine, dopamin & serotonin

Question 4

Name some Amino acid neurotransmitters

Answer 4

GABA, glutamate

Question 5

What is peptide neurotransmitters made of? And name some.

Answer 5

made up of short chains of amino acids.
Ex. Opioid peptides : Enkeplalin, Endorphins, Dynorphins.
Other: Oxytocin, Substance P, cholecystokinin ect.

Question 6

What is the difference between ionotropic (also called ligand-gated ion channel) receptors and metabotropic receptors?

Answer 6

In ionotropic receptors neurotransmitters open the ion channel directly in the postsynaptic cell’s membrane. - They are fast receptors

At metabotropic receptors the neurotransmitters, activate the receptor which further activates G-proteins that open other ion channels and/or cause other changes in the postsynaptic cell. - The are slow receptors (p. 93)

Question 7

What is a ligand?

Answer 7

A substance that binds to receptor molecules, such as those at the surface of the cell.

Question 8

A ligand can have three types of effects. Name the three and explain them.

Answer 8

1) - AGONIST - A ligand that is classified as an agonist initiates the normal effects of the transmitter on that receptor.
2) ANTAGONIST- A recepter antagonist is a lignad that binds to a receptor and does not activate it, thereby blocking it from being activated by other ligands.
3) INVERSE AGONISTS - An inverse agonist (a less common type of ligand) binds to the receptor and initiates an effect that is the reverse of the normal function of the receptor. (p. 94)

Question 9

Explain the difference between competitive and noncompetitive ligands.

Answer 9

Competitive ligands bind the the same part of the receptor complex that the endogenous transmitter normally would. (Doesn’t let other transmitter to the receptor)

Noncompetitive ligands binds to a modulatory site on the receptor so other transmitters can access the receptor. (p. 94)

Question 10

There are two families of ACh-receptors in the peripheral and central nervous systems. What are they called?

Answer 10

Nicotinic and muscarinic receptors.

Question 11

Can anyone beat Sebastian 1on1 mid?

Answer 11

No. (Første mosebog 1:1; De ti bud 1/10)

Question 12

Name some general characteristics of nicotinic and muscarinic receptors.

Answer 12

Most nicotinic receptors are ionotropic, responding rapidly and usually having an excitatory effect.

Muscarinic ACh receptors are G protein-coupled (metabotropic) receptors, so they have slower responses when activated, and they can be either excitatory or inhibitory. (p. 95)

Question 13

Name the two principal classes of monoamines

Answer 13

Catecholmanines and indoleamines.

Question 14

Explain why Catecholmanines and indoleamines are called monoamines.

Answer 14

Because both neurotransmitters are modified amino acids.

Question 15

Name the 3 catecholamine neurotransmitters

Answer 15

Dopamine, Epinephrine and Norepinephrine (They are all derived from the amino acid tyrosine)

Question 16

Name the 2 indoleamine neurotransmitters

Answer 16

Melatonin and serotonin (they are both derived from the amoni acid tryptophan) (p. 95).

Question 17

What are the two dopaminergic pathways in the brain?

Answer 17

Mesostriatal pathway: Substantia nigra to striatum (caudate and putamen)
Mesolimbocortical pathway: Ventral tegmental area (VTA) to nucleus accumbens, cortex (including the insula) and hippocampus. Look at the picture @ p. 95.

Question 18

Name the two main clusters of neurons in the brainstem releasing norepinephrine.

Answer 18

Locus coeruleus, in the pons.

and the lateral tegmental system of the midbrain.

Question 19

What is the difference between norepinephrine and noradrenaline?

Answer 19

There are none. Norepinephrine is also known as noradrenaline, which is why NE-producing cells are said to be noradrenergic.

Question 20

What neurotransmitter is abbreviated 5-HT?

Answer 20

Serotonin, because the chemical name is 5-hydroxytrptamine.

Question 21

Where are the 5-HT cell bodies concentrated?

Answer 21

Along the midline in the raphe (“rafay”) nuclei of the midbrain and brainstem.

Question 22

Is it true that generally many neurons in the brain are serotonergic?

Answer 22

No. Only 200,000 of the 100 billion neurons are serotonergic.
However they do exert widespread influence through the rest of the brain.

Question 23

Name some of the human functions that serotonin has been implicated in.

Answer 23

The control of sleep states, mood, sexual behavior, anxiety, and many other functions. (p. 97).

Question 24

What is the most common transmitters in the brain?

Answer 24

Amino acids.

Question 25

Name some amino acids. And name wether they are inhibitory or excitatory

Answer 25

Glutamate and aspartate are important excitattory neurotransmitter.
GABA (Gamma-aminobutyric acid) and glycine typically have an inhibitory effect. (p. 97)

Question 26

Name which receptors glutamatergic transmission employs.

Answer 26

AMPA, kainate, and NMDA receptors.

These receptors are implicated in different functions - read of these @ p. 97.

Question 27

GABA receptors are also divided into large classes, which all exhibit quite different properties. Name the classes and their properties.

Answer 27

GABA_a: ionotropic, produces fast inhibitory postsynaptic potentials.
GABA_b: Metabotropic receptors, typically producing slow-occuring inhibitory postsynaptic potential.
GABA_c: ionotropic with a chloride channel, they differ from other GABA receptors in certain details of their subunit structure. (p. 97f).

Question 28

Many peptides function as neurotransmitters. Three types are relevant in the book. Name them.

Answer 28

• The opioid peptides.
• A group found in the gut and spinal cord or brain, including substance P, cholecystokinin, neurotensin etc.
• Pituitary hormones such as oxytocin and vasopressin etc. (p. 98)

Question 29

Name the primary ways drugs can affect the brain.

Answer 29

By altering enzyme action or modifying other internal cellular processes. But most drugs of interest in biological psychology are receptor ligands. (p. 98)

Question 30

What is a good analogy to describe how drugs interact with receptors?

Answer 30

Drugs fit like keys into molecular locks.

Drug molecules do not seek out particular receptor molecules; rather, drug molecules spread widely throughout the body, and when they come in contact with a receptor molecule possessing the correct shape, the two molecules bind together briefly and begin a chain of events. (p. 99).

Question 31

What is meant by the binding affinity of a drug?

Answer 31

A drug with high affinity for a particular type of receptor will selectively bind to that type of receptor even at low doses, at it will stay bound for a relatively long time.

Low affinity drugs will bind fewer receptor molecules. (p. 100)

Question 32

What is meant by the term: efficacy, when talking about ligands?

Answer 32

The propensity of a ligand to activate the receptor to which it is bound is termed efficacy.
Agonists have high efficacy and antagonists have low efficacy. (p. 100)

Question 33

Why is affinity and efficacy important?

Answer 33

It is a combination of affinity and efficacy that determines the overall action of a drug, which is especially important to determine the right dose of the drug. (p. 100f)

Question 34

Does a specific drug always have the same potency?

Answer 34

No. The body often adapts to the administered drug: Makes drug tolerance. (p. 101)

Question 35

Name different types of tolerances.

Answer 35

Metabolic tolerance: The body’s metabolic systems and organs (such as the liver) become increasingly effective at eliminating the drug.

Functional tolerance: The target tissue show altered sensitivity to the drug. Ex. the receptor proteins to a specific drug may down-regulate or up-regulate. Depending on wether the drug is an agonist or antagonist. (p. 101f)

Question 36

Does the body always build tolerance towards drugs?

Answer 36

No. Some drug responses can become stronger with repeated treatments. Termed sensitization. (p. 102)

Question 37

Name the four routes of administering drugs.

Answer 37

Ingestion, Inhalation, Peripheral injection and Central injection. (p. 103)

Question 38

Drugs can target both/either the presynaptic cell and/or the postsynaptic cell. Name ways the presynaptic cell can be affected.

Answer 38

The drug can affect the transmitter production, transmitter release and transmitter clearance (the reuptake or degradation of transmitters) (p. 105)

Question 39

Drugs can target both/either the presynaptic cell and/or the postsynaptic cell. Name ways the postsynaptic cell can be affected.

Answer 39

Effects on the transmitter receptors and effects on the cellular processes. (p. 107)

Question 40

Drugs that affect the brain can be divided into functional classes. Name the classes

Answer 40

Antipsychotic drugs - Relieve the symptoms of schizophrenia.
Antidepressants - Relieve chronic mood problems.
Anxiolytics - Combat anxiety
Alcohol - Has several effects.
Opiates - Help relieve pain.
Cannabiniods - have a wide array of effects.
Stimulants - Increase the activity of the nervous system
Hallucinogenic and dissociative drugs - alter sensory perception. p. 107-116.

Question 41

Should you read about the different variaties of functional drugs?

Answer 41

Maybe.. If you want to read p. 107-116.

Question 42

Comprehensive models of drug abuse has been made, that each tries to answer the questions: What social and environmental factors cause someone to start abusing a substance? What factors cause the person to continue? What physiological mechanisms make a substance rewarding? What is addiction, physiologically and behaviorally? Name the 4 different models

Answer 42

The moral model: Simply blaming the substance abuser for a failure of moral character / lack of self-control.

The disease model: The person who abuses drugs requires medical treatment rather than moral exhortation or punishment.

The physical dependence model: Argues that people keep taking drugs in order to avoid unpleasant withdrawal symptoms.

The postive reward model: Proposes that people get started with drug abuse, and become addicted, because the abused drug provides powerful reinforcement. (p. 116-118)

Question 43

Name brainareas that are affiliated with addiction.

Answer 43

Many addictive drugs cause release of dopamine in nucleus accumbens.
The dopaminergic pathway from the VTA to the nucleus accumbens serves as a reward system. So its most like the neural pathway VTA –> Amygdala –> Nucleus accumbens. (p. 118f)
Insula may also be involved in addiction, as people with damage to insula have no problem quitting smoking.