Biological Psych 6: Psychopharmacology (Lec 30)

Question 1

What did Loewi show w frog hearts?

Answer 1

That there are neurotransmitters which slow and increase speed of heart-beat, by placing the hearts in 2 beakers of solution w a shared p/way

Question 2

Neurotransmission is an electrical to chemical to electrical signal. Please explain this

Answer 2

AP in neuron causes calcium channels to open (Ca+), Ca+ rushes in and causes proteins to fuse w extracellular membrane, causing the cute little vesicles to open up and spill their neurotransmitter contents into the synaptic cleft.

Then the neurtransmitters bind to proteins which changes the electrical gradient across the post-synaptic membrane

Question 3

There are 6 major classes of neurotransmitters. List the subclass/es and neurotransmitter/s which belong to each group, and name the primary group.

• Amino acids
• Cholines
• Monoamines
• Peptides
• Lipids
• Nucleotides

Answer 3

-Amino acids (primary neurotransmitters) =
Excitatory: Glutamate
Inhibitory: GABA

-Cholines
Acetylcholine (nicotinic/ muscarinic receptors)

-Monoamines:
Catecholines:
Noradrenalin/ norapinephrin (Alpha/ Beta/ Adreinergic receptors)
Dopamine (DA) (D1-5 receptors)

Indolamine:
Seatonin 5HT (14 receptor types)!

-Peptides
Opioid:
Endorphines (opioid receptors)

-Lipids
Endocannabinoids
Anadamide (cannibinoid receptors)

-Nucleotides
Purine
Adenosine (adensine, purinergic receptors)

Question 4

What are the main excitatory amino acid receptors for glutamate? How widespread is the release of glutamate?

Answer 4

Glutamate: NDMA, AMPA, mGlu and kainate

Glutamate is released by most neurons

Question 5

What are the receptor types for GABA, the main inhibitory amino acid?

Which neurons release GABA?

Answer 5

GABA: GABA-A and GABA-B

GABA is by specialist inhibitory neurons

Question 6

Dopamine and noredrenalin/ norepinephrine (NA) are which types of monoamines?

Answer 6

Catecholamines

Question 7

Dopamine and noredrenalin /norepinephrine (NA) are which types of monoamines, and what do they bind to?

Answer 7

Catecholamines

Dopamine binds to dop receptors 1-5
Noredrenelin binds to alpha and beta adrenergic receptors

Question 8

Serotonin (5HT) is what type of monoamine? How many types of receptors are there?

Answer 8

Indolamine, there are 14 types of receptors, both inhibitory and excitatory

Question 9

What is the main sub-class of peptide and what do they bind to?

Answer 9

Opioids, opioid receptors

Question 10

Give an example of some fatty compounds which form neurotransmitters

Answer 10

Class: Lipids, sub-class: endocannibinoids, Endogenous ligand (neurotransmitter protein which binds to receptor): Anandamine, Receptor type: Cannabinoid

Question 11

What are nucleosides?

Answer 11

Found in DNA, they’re neurotransmitters with receptors such as adenosine and purinergic

Question 12

Which acids form the primary type of neurotransmitter?

Answer 12

Amino acids eg glutamate/ GABA

Question 13

What is a major difference between amino acids (glutamate/ GABA) and monoamines (5HT, Dop &NA)?

Answer 13

Amino acids are released by most neurons, whereas monoamines are more discrete; these neurons are only produced in limited locations of the brain but their effects are spread all over the brain

Question 14

How many nuclei produce neurons which can transmit the monoamine dopamine, and where do these neurons project?

Answer 14

2; substantianigra, which projects into the striatal system, & VTA- ventral tegmental area, which has multiple projections into areas important for emotional processing & into cortex

Question 15

How many nuclei produce neurons for the monoamine noradrenalin, and where does it project?

Answer 15

One part of brain, spreads all over the brain eg cerebellum (regulates m.ment) and down to spinal chord (pain perception)

Question 16

How many nuclei produce neurons for the monoamine seratonin, and where do they project?

Answer 16

3 main nuclei, neurons spread all over the nervous system to regulate and change diff nuclei around the brain

Question 17

What are the 2 major types of neurotransmitter receptors, and how do they both open?

Answer 17

Ionotropic
• Neurotransmitter opens an ion channel

– Metabotropic
• Neurotransmitter started an enzymatic cascade within the neuron

Question 18

What happens when a drug binds to a receptor?

Answer 18

It causes a conformational change effecting the ‘tail’ of the receptor

Question 19

What kind of coefficients determine the stickyness of the drug for the receptor?

Answer 19

K coefficients

Question 20

What was the first type of receptor to be represented by crystalography?

Answer 20

the GABA receptor

Question 21

how do GABAergic neurons act as inhibitory?

Answer 21

When GABA binds to the receptor site and the channel opens, Cl- comes through, making the charge inside the cell more -ve

Question 22

What kind of receptors are GABA receptors?

Answer 22

Ionotropic (Cl- enters, making charge more -ve inside neuron)

Question 23

Name 2 neurotransmitters which utilise metabotropic receptors

Answer 23

GABA-B and dopamine

Question 24

Briefly describe the simpler type of metabotropic receptor process

Answer 24

When the neurotransmitter binds to the receptor, the receptor activates a G protein; the alpha subunit of that G protein breaks away and binds to an ion channel at the cells membrane allowing +ve ions to enter the cell, producing a post-synaptic potential

Question 25

What is the difference between the two types of metabotropic receptors?

Answer 25

One type utilises enzymes which create a 2nd messenger; this can not only change the electric potential of the cell membrane but also contact other parts of the cell including the nucleus, changing the genetic activity within the cell. This would cause long-term changes to the neuron’s functionality.

Question 26

Name a functionality of reuptake, and the 2 outcomes

Answer 26

Reuptake allows faster signalling.

Neurotransmitters are either repackaged in vesicles or destroyed by enzymes in the presynaptic neuron

Question 27

What is the difference between an agonist and an antagonist?

Answer 27

An agonist mimics neurotransmitters by binding to the receptor, it fits the lock shape perfectly triggering post-synaptic potential change at the post-synaptic neuron membrane.

An antagonist blocks the lock-shape against neurotransmitter binding, although it doesn’t fit perfectly, they fit well enough to block the binding of natural (endogenous) or drug (exogenous) agonists.

Question 28

What is the effect of L-dopa and how does it work?

Answer 28

It increases the catecholamine dopamine’s availability by restoring generation to ‘normal’ function

Question 29

What are the 4 types of agonist mechanisms?

Answer 29

1. Increasing availability of n.transmitter by enhancing release
2. Mimicking neurotransmitter by binding directly to receptor
3. Block reuptake of transporter proteins
4. Blocking enzymes which destroy neurotransmitters

Question 30

Name 5 agonist drugs which bind directly to receptors

Answer 30

• THC binds directly to cannabinoid receptors
• Benzodiazepene (Valium) & Ethanol binds to GABA receptors
• Heroin to opioid receptors
• Nicotine to nicotine receptors

Question 31

Name agonist drugs which utilise the reuptake blocking mechanism

Answer 31

• MDMA & SSRIs block reuptake of seratonin
• Tricyclic antidepressants block reuptake of 5HT &noradrenaline
• Cocaine blocks dopamine transporters

Question 32

Give an example of a drug which reverses trasporter protein activity, causing the proteins to release the neurotransmitter

Answer 32

Amphetamines: Dopamine gets dumped in uncharacteristically large amounts

Question 33

What type of agonist antidepressants block monoamine oxidase enzymes, and what do these enzymes do?

Answer 33

Monoamine oxidase enzyme inhibitors (MAOIs):

• MAOA drugs blocking the degradation of serotonin and noradrenaline are used for anxiety & depression
• MAOB drugs blocking the degradation of dopamine are used for Parkinsons and Alzheimer’s

Question 34

What is the main function of antagonist drugs?

Answer 34

They mainly block neurotransmitters from binding to receptors

Question 35

Give 4 examples of some antagonist drugs….

Answer 35

• Naxolone blocks opioid receptors
• Ketamine blocks NMDA (glutamate) receptors
• Anti-psychotics such as haloperidol block D2 dopamine receptors
• Beta blockers such as propranolol (used to treat high blood pressure) block the beta-adrenergic receptor (interacts w epinephrine)

Question 36

Which were the first antidepressants discovered and when was this? Why are they not used so much these days? Give an example.

Answer 36

MAOIs, in 1952

Severe side effects. An example is that they interacted with a lot of foods including cheese and foods from all food groups containing tyramine

Question 37

What did the discovery of MAOIs contribute to the depression hypothesis?

Answer 37

The monoamine depression hypothesis: Future anti-depressants were designed to increase synaptic monoamines

Question 38

What is one possible reason that depression can become more acute after taking antidepressants?

Answer 38

It could be a chronic downstream effect, meaning that the body compensates for the new high levels of NA/ DA/ 5HT

Question 39

What is the receptor sensitivity hypothesis? (Explaining the ineffectivity of antidepressants fro some ppl). Use 5HT as an example (SSRIs)

Answer 39

Too many 5HT1A on pre-synaptic neurons and too many 5HT2A receptors on post-synaptic neurons causes chronic elevation of 5HT. These receptors are then reduced over time to normalise synaptic function.

Question 40

What are some other adaptive changes which can be caused by SSRIs?

Answer 40

heightened 5HT2A receptors initiates cellular changes such as gene expression and upregulation of receptors such as glucocorticoids in the hippocampus.

The creation of hormones which initiate new synapse formation or cause neurogenesis (new neuron growth).

Question 41

What is downregulation/ upregulation?

Answer 41

Downregulation= the reduction of cellular component such as RNA or protein, in response to an external stimulus.

Upregulation is the increase of that cellular component