Brainscape's Knowledge GenomeTM

Browse over 1 million classes created by top students, professors, publishers, and experts.


See full index

Module 202 Theme 1 > How drugs control the brain > Flashcards

How drugs control the brain Flashcards

1
Q

Where is GABA mainly used?

A

Inhibitory interneurons - keep the excitation in check

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Which neurotransmitter uses glutamine?

A

Projection neurons

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

Which neurotransmitter controls local interneurons?

A

GABA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Describe the GABA(A) ionotropic receptor

A

Ligand gated Cl- channel
Fast IPSPs
Mainly GABAergic interneurons
Heteropentameric structure 2 alpha and 3 more subunits
CL- channel gated by the binding of two agonist molecules. Cl - potential is near resting potential increasing chloride permeability hyperpolarizing the neuron decreasing the depolarizing effects of the excitatory input

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

Describe GABA(B) metabotropic receptors

A

G protein coupled receptors
Indirectly coupled to K+ and Ca2+ channel through 2nd messengers
Slow IPSPs
Both pre and postsynaptic

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

Name a direct agonist of the GABA(A) receptor

A

Muscimol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Name a direct antagonist of GABA(A) receptor

A

Bicuculline

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Name an indirect agonist of GABA(A) receptor

A

Benzodiazepine - binding increase the receptor affinity for GABA, increase frequency of channel opening, anxiolytic and hypnotic drugs with rapid onset but less satisfactory in the long run (addiction)

Barbiturates increase the duration of channel openings (anaesthesia)

Alcohol

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe how benzodiazepines work

A

Benzodiazepine binding site on the a subunit of GABA(A) receptor
benzodiazepine binds to a subunit, changes conformation of the receptor so GABA activation of receptor is more effective.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the effects of benzodiazepine

A 
Effects to: 
reduce anxiety
cause sedation
reduce convulsions
relax muscles
cause amnesia
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

Describe the action of alcohol and barbiturates on the GABA(A) channel

A

to enhance GABA(A) activity and effects are additive - combining the two can be fatal

Alcohol also interacts with NMDA, glycine, nicotinic and serotonin receptors.

Low doses of alcohol - mild euphoria and anxiolytic effects Higher doses - incoordination, amnesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

Name an agonist of a GABA(B) channel

A

Baclofen

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe how the GABA(B) receptor works

A

Gi coupled - inhibits adenylyl cyclase
Gbg gated K+ channels
increases K+ conductance
decreases Ca2+ conductance (presynaptically)
Slow hyperpolarizing current (late inhibitory postsynaptic potential)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is the main function of glutamate neurons?

A

primary route of sensory and motor information and relay neurons between brain areas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is the main function of GABA neurons?

A

interneurons, maintain balance between excitation and inhibition

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

List some patterns of communication in the nervous system

A

Point-to-point systems
Hormones released by the hypothalamus
ANS neurons activating body tissues
Diffuse modulatory system with divergent axonal projections (not classical synapse)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Where are the dopamine neurons?

A

Cell bodies in the midbrain and project into the forebrain

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does the nigrostriatal system do?

A

75% of brain dopamine
Motor control
Cell bodies in the substantia nigra project to the striatu, (caudate nucelus and putamen) Importnat part of basal ganglia involved in movement.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What does the mesocortical system do?

A

Responds to addictions and the environment
VTA projections to prefrontal cortex

Role in functions such as working memory and planning.

20
Q

Describe the D1 like receptor (1 and 5)

A

Gs - stimulate adenylyl cyclase
- stimulate phospholipase C
postsynaptic

21
Q

Describe the D2 like receptor (2,3,4)

A 
Gi  	- inhibit adenylyl cyclase
				- open K+ channels
				- close Ca2+ channels
			postsynaptic
			presynaptic autoreceptors (D3)
22
Q

What maintains the balance of dopamine concentration?

A

Balance of D1 and D2

23
Q

Describe dysfunction of the nigrostriatal system

A

Parkinsons disease - destruction of DA projections from SN to basal ganglia
Huntington’s disease - destruction of DA target neurons in striatum

24
Q

What drugs are used in the treatment of parkinsons?

A

L-DOPA, Monoamine oxidase (MAO) inhibitors, Dopamine receptor agonists -treatments for Parkinson’s Disease

25
Q

What is the mesolimbic system?

A

cell bodies in ventral tegmental area (VTA) project to the limbic system, nucleus accumbens (NAcc)

Role in reinforcement (reward) of several categories of stimuli, including drugs of abuse

26
Q

Describe the dysfunction of the mesolimbic system

A

Addiction - most drugs of abuse lead to enhanced DA release in the NAcc

27
Q

Name some drugs that affect the mesolimbic system

A

e.g. Cocaine and Amphetamine - psychomotor stimulants
Immediate effects
- give the feeling of increased alertness and self confidence, a sense of exhilaration and euphoria and a decreased appetite.
- large doses can cause stereotypy and psychosis
- cause peripheral effects that mimic activation of the sympathetic division of the ANS, increased heart rate and blood pressure, dilation of pupils etc.
Long-term effects
- natural rewards, e.g. water, food, sex increase DA transmission and leads to reinforcement of associated behaviours
- increased DA by cocaine etc. short circuits pathway, drug taking behaviours become reinforced
- downregulation of endogenous DA system - craving

28
Q

Describe dysfunction of the mesocortical system

A

Scizophrenia

29
Q

Name some drugs affecting the mesocortical system

A

Typical antipsychotics (e.g. chlorpromazine and haloperidol)
- DA receptors antagonists (pre and postsynaptic)
- Increase DA turnover - lose autoreceptor inhibiton
- Blockade of postsynaptic receptors - upregulation
Antipsychotic effects - action in mesocortical system
Side effects - action on other dopaminergic systems
Extrapyramidal side effects (EPS) - tardive dyskinesia etc.
(chronic blockade causes system to become supersensitive)
Atypical antipsychotics (e.g. clozapine)
- specific to receptor subtype
e.g. Clozapine - antagonist of D4 receptors (cortex only)
Reduce psychosis associated with schizophrenia
Antipsychotic effects without EPS

30
Q

Describe the serotonergic system

A

Nine raphe nuclei in reticular formation with diffuse projections
-each projects to a different part of the brain

Descending projections to cerebellum and spinal cord (pain)
Ascending reticular activating system (with LC)

Dorsal and medial raphe, project throughout the cerebral cortex

raphe neurons fire tonically
during wakefulness

quiet during sleep

31
Q

List the functions of the serotonergic system

A

mood

sleep

pain

emotion

appetite

32
Q

Name a selective serotonin reuptake inhibitor SSRI

A

Fluoxetine (PROZAC)

33
Q

Describe how selective serotonin reuptake inhibitors work

A

increase serotonin function by preventing its uptake

treatment for depression and anxiety disorders

but depression not a simple case of low serotonergic tone
(effects not seen for 2-3 weeks)
increased availability of serotonin triggering downstream pathways
- long term modulatory effects
- second messenger cascades, gene transcription etc. synthesizing new receptors and changing pathways and cascades in the cell

34
Q

How does MDMA (ecstasy) affect the serotonergic system?

A 
causes serotonin (and norepinephrine) transporters to run in reverse
increased release of serotonin and blocked reuptake
35
Q

Describe how LSD affects the serotonergic system affects the serotonergic system?

A

Causes a dreamlike state with altered sensory perceptions

LSD potent agonist at 5HT1A receptors in raphe nucleus

Hallucinogenic properties at 5HT2A receptors in prefrontal cortex

36
Q

Describe the noradrenergic system

A

Projections form the Locus Coeruleus throughout the brain

Role in arousal and attention

Metabotropic receptors

Alpha adrenergic receptors
a1 Gq
a2 Gi

Beta adrenergic receptors
b1, 2 and 3 Gs

37
Q

Describe the adrenergic system

A

Primarily in lateral tegmental area, projecting to thalamus and hypothalamus.

Acts on a- and β- adrenergic receptors

38
Q

Describe the cholinerggic system

A

In the periphery
Acetylcholine at NMJ and
synapses in the autonomic ganglia

In the brain
Basal forebrain complex
Cholinergic innervation of the
Hippocampus and the neocortex

Brain stem complex
innervates the dorsal thalamus and telencephalon
-control excitability of sensory relay neurons and provide a cholinergic link between the brain stem and basal forebrain complex

39
Q

List some disorders of the cholinergic system

A

Peripheral
Myasthenia gravis
Autoimmune disease - destroys cholinergic receptors in the muscle - muscle weakness and eventual loss of muscle activity

Brain
Alzheimer’s disease
Loss of cholinergic neurons in the basal ganglia - possibly underlies deficits in memory associated with the disease.

Addiction: nicotine addiction

Epilepsy
Autosomal dominant nocturnal frontal lobe epilepsy (ADNFLE) associated with mutations in nicotinic receptor genes.
Other psychiatric disorders
Comorbidity with smoking

40
Q

How do acetylcholinesterase inhibitors work?

A

Prolong action of acetylcholine at the synapse

  • Treatment for Alzheimer’s disease (e.g. physostigmine)
  • Treatment for Myasthenia gravis (neostigmine)
41
Q

How does botox work?

A

Prevents release of ACh at the NMJ

42
Q

How does latrotoxin work?

A

Permanent release - depletes ACh at NMJ

43
Q

Name the two types of acetylcholine receptor

A

Muscarinic - metabotropic

Nicotinic - ionotropic

44
Q

What is the agonist of the muscarinic receptor?

A

Muscarine

45
Q

What is the antagonist of the muscarinic receptor?

A

Atropine

46
Q

Describe the action of muscarinic receptors - metabotropic

A

Lead to opening or closing of K+, Ca2+ or Cl- channels
hyperpolarization or depolarization (cell type/receptor type dependent)

Pre and postsynaptic receptors
Presynaptic autoreceptors - negative feedback - stop ACh release

47
Q

Describe the histaminergic system

A

Arousal & attention
Reactivity of vestibular system
Mediation of allergic responses
Influence of brain blood flow

3 G-protein-coupled Rs

Module 202 Theme 1 (28 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2024 Bold Learning Solutions. Terms and Conditions