Lecture 4- Chemical Signaling And Neuromodulation

Question 1

What is neuromodulation

Answer 1

It modulates the activity of the neuron, alters the speed of the neurone

Question 2

Neuropeptides are

Answer 2

Endorphins

Question 3

Amino acid transmitters are responsible for

Answer 3

Fast transmission

Question 4

What is glutamate responsible for

Answer 4

Excitatory causing next neurone to fire

Question 5

What are GABA and Glycine responsible for

Answer 5

Inhibitory

Question 6

Glutamate synthesised from

Answer 6

Glucose or glutamine

Question 7

Glutamate is released by

Answer 7

Exocytosis (Ca+ dependent mechanism)

Question 8

Too much glutamate can cause

Answer 8

Hyperexcitability (epilepsy)

Question 9

Too little GABA can cause

Answer 9

Hyperexcitability (epilepsy)

Question 10

What is cerebral ischemia

Answer 10

• Insufficient blood flow due to plaque
• Due to High glutamate
• Reversal of the Na+ K+ gradient

Question 11

Receptors vary in

Answer 11

Pharmacology (what transmitter binds and how drugs interact)

Question 12

What are agonist drugs

Answer 12

Produce a cellular reaction when bound to receptor

Question 13

What is an antagonist drug

Answer 13

• Reduces or completely blocks the activity of an agonist

- No cellular effect

Question 14

Receptors vary in their

Answer 14

• Kinetics (rate of binding)
• Selectivity (what binds)
• Conductance (rate of flux)

Question 15

Glutamate receptors allow

Answer 15

Sodium ions influx

Excitatory

Question 16

GABA receptors cause

Answer 16

Chloride (Cl-) influx

Inhibitory

Question 17

What are the three types of glutamate receptors

Answer 17

• AMPA
• NMDA
• Kainate
• Named on the agonist that binds with glutamate

Question 18

AMPA receptor is

Answer 18

• Iontropic receptor
• Leads to opening of Na+ channel
• Causes depolarisation

Question 19

NMDA receptor features

Answer 19

• iontropic receptor
• it’s Non-competitive antagonist is PCP
• Needs glutamate and glycine to bind
• Permeable to Na+, K+ and Ca+
• Voltage gated

Question 20

Which has slower kinetics, NMDA or AMPA

Answer 20

NMDA

Question 21

AMPA and Kainate are permeable to

Answer 21

Na+ and K+

Question 22

NMDA receptors are only activated in

Answer 22

An already depolarised membrane in the presence of glutamate.
This allows the magnesium blocking NMDA to be dispelled

Question 23

What are NMDA receptors blocked by

Answer 23

• Magnesium

- PCP (the drug)

Question 24

Certain antipsychotic drugs enhance current flow through

Answer 24

NMDA channels

Question 25

Glutamate excitotoxicity caused by

Answer 25

Excessive Ca+ influx which activate things that damage the cell Occurs after stroke

Question 26

NMDA receptors associated with what illness

Answer 26

Schizophrenia

Question 27

Too much GABA can cause

Answer 27

Sedation, coma

Question 28

GHB (date rape drug) causes

Answer 28

Increases amount of available GABA

Question 29

Alcohol acts at what receptor

Answer 29

GABA a

Question 30

GABAa receptor

Answer 30

- Iontropic - Ligand gated Cl- channel - Fast IPSP - Inhibitory - Multiple binding sites

Question 31

GABAb receptors

Answer 31

- Metabotropic receptor - G protein coupled receptor - Indirectly coupled to K+ (opens) or Ca2+ (closes) channels - Slow IPSPs - Inhibitory

Question 32

GABAa increases

Answer 32

Chloride permeability and hypolarises the neuron

Question 33

What’s GABA agonist and antagonist

Answer 33

Agonist- muscimol (a mushroom) | Antagonist- bicuculine, picrotoxin

Question 34

Drugs increasing GABA activity reduce anxiety

Answer 34

Agonist- Alcohol, barbiturates | Indirect antagonist- Benzodiazepines

Question 35

Drugs decreasing GABA activity increase anxiety

Answer 35

Antagonist- Flumazenil (reverses effects of benzodiazepines)

Question 36

Patients with panic disorders have less

Answer 36

Benzodiazepine binding dites

Question 37

If you have GABA and the barbiturate it results in

Answer 37

Bigger hyperpolerisation

Question 38

When be benzodiazepines are applied on their own it results in

Answer 38

- No effect | - GABA and benzodiazepines results in an effect

Question 39

Problems with barbiturates

Answer 39

- General depression of neuronal activity, can result in not breathing - Poor therapeutic ratio (small difference between dose and overdose) - Long term treatment leads to dependence

Question 40

Why are benzodiazepines better for calming anxieties

Answer 40

- Indirect antagonist on its own - Fast acting - Large therapeutic window

Question 41

Disadvantages of benzodiazepines

Answer 41

- May cause dependence | - Effects potentiated by alcohol

Question 42

Dopamine neurons are where

Answer 42

- Cell bodies in the midbrain | - Project into the forebrain

Question 43

3 key dopamine pathways

Answer 43

- Role in movement - Role in reinforcement - Role in working memory and planning

Question 44

Damage to movement system (nigrostiatal system)

Answer 44

- Parkinson’s disease | - Huntington’s disease

Question 45

Damage to reward system (mesolimbic system)

Answer 45

Addiction to drugs

Question 46

Damage to working memory system (mesocortical system)

Answer 46

Schizophrenia

Question 47

Dopamine synthesis

Answer 47

- Tyrosine to - L-Dopa to - Dopamine

Question 48

What drugs affect dopamine synthesis

Answer 48

- Reserpine, impairs storage of dopamine | - L-DOPA, precursor of dopamine, used to treatment for Parkinson’s disease, increases dopamine

Question 49

AMPT inactivates

Answer 49

TH

Question 50

Dopamine release causes

Answer 50

- Depolarisation of presynaptic membrane | - Influx of Ca2+ through voltage gated Ca2+ channels

Question 51

After release, cytoplasm dopamine is

Answer 51

Reloaded back into vesicles and enzymatically degraded

Question 52

Drugs that affect dopamine release and reuptake

Answer 52

- Cocaine, amphetamine and methylphenidate - Selegiline - Entacapone

Question 53

What do psychostimulants (cocaine) do to dopamine release

Answer 53

- Block reuptake of monamines | - Extended action of dopamine on postsynaptic neuron

Question 54

What can drugs that affect dopamine release and reuptake also do

Answer 54

- Have antidepressant activity | - Can treat Parkinson’s

Question 55

What does the noradrenergic system do

Answer 55

- Role in arousal and attention | - Role in anxiety, heroin withdrawal, depression

Question 56

Where does the serotonergic system project

Answer 56

Throughout the cerebral cortex

Question 57

What does the serotonergic system function in

Answer 57

- Mood - Sleep - Pain - Appetite

Question 58

Process of serotonin synthesis

Answer 58

- Tryptophan - 5-hydroxytryptophan - Serotonin

Question 59

More tryptophan might help

Answer 59

Improve your mood

Question 60

Serotonin released through

Answer 60

Ca2+ dependent mechanism

Question 61

What degrades dopamine and serotonin

Answer 61

MAOs

Question 62

Drugs that affect serotonin

Answer 62

- Fluoxetine (Prozac) - Fenfluramine - MDMA

Question 63

What does fluoxetine do

Answer 63

Blocks reuptake of serotonin | Antidepressant

Question 64

What does fenfluramine do

Answer 64

Causes release of serotonin and inhibits it’s reuptake. | Appetite suppressant

Question 65

What does MDMA do

Answer 65

- Causes noradrenaline and serotonin transporters to run backwards. - Neurotransmitters into synapse

Question 66

What is acetylcholine synthesised from

Answer 66

Choline

Question 67

What can acetylcholinesterase inhibitors do

Answer 67

- Treat Alzheimer’s - Myasthenia gravis - Autoimmune disorders

Question 68

Drugs that affect vesicle docking and release

Answer 68

- Botox - Botulinum - tetanus toxins

Question 69

Tetanus prevents

Answer 69

Glycine release

Question 70

Tetanus toxin causes

Answer 70

Disinhibits the cholinergic neurons so they continually fire resulting in permanent muscle contraction