Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

202 retake: theme 1 > L13 How Drugs Control the Brain > Flashcards

L13 How Drugs Control the Brain Flashcards

(45 cards)

Start Studying
1
Q

describe and state the Two main families of GABA receptor:

A

1) GABA(A) ionotropic receptors

Ligand gated Cl- channel

Fast IPSPs
       Mainly GABAergic interneurons

2) GABA(B) metabotropic receptors

	G protein coupled receptors
	Indirectly coupled to K+ or Ca2+ channel through 2nd messengers
	(opens K+ channel, closes Ca2+ channel)
	Slow IPSPs
	Both pre- and post- synaptic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

describe the structure of GABA (A) receptors

A

-Heteropentameric structure - 2 a + 3 more subunits

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

describe what occurs when a GABA(A) receptor is activated

A
  • Cl- channel gated by the binding
    of two agonist molecules
                     Cl- potential is near resting potential 
                 increasing chloride permeability 					       hyperpolarizes the neuron 		
                 decreasing the depolarizing effects of 
                 an excitatory input
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

where do indirect and direct antagonists bind to a GABA receptor

A
  • bind at GABA binding site
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

state and describe a direct agonist

A

Muscimol – agonist

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

state and describe a direct antagonist

A

Bicuculline – antagonist (experimental tool)

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

state and describe an indirect agonist

A

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

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

state and describe an indirect agonist

A

Barbiturates increase the duration of channel openings (anaesthesia, epilepsy treatment)

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

state and describe an indirect agonist

A

Alcohol - agonist

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

go into more detail about the actions of a benzodiazepine on GABA (A) and give an example

A
  • diazepam (Valium)
  • Benzodiazepine binding site on the a subunit of GABA(A) receptor

Indirect agonist - benzodiazepine binds to a subunit, changes conformation of the receptor so GABA activation of receptor is more effective.

Effects of benzodiazepine are to:

  • reduce anxiety
  • cause sedation
  • reduce convulsions
  • relax muscles
  • cause amnesia

Inverse agonists bind to benzodiazepine site and have opposite effects

– produce anxiety and predisposition to convulsions
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

describe in more detail the pharmacology of barbiturates and alcohol on GABA(A)

A

Bind at different sites on the receptor

Both have same effect: 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 and describe an agonist for a GABA(B) receptor

A

Agonist - Baclofen (used as a muscle relaxant to reduce spasticity e.g. in Huntington’s disease)

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
13
Q

does inhibition of a GABA(B) transmission have the same effect as on a GABA(A) transmission

A

NO- Inhibition of GABA(B) transmission does not have same behavioural outcome as inhibition of GABA(A) receptors (e.g. seizure)

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

name some diffuse modulatory systems

A 
Dopaminergic (DA)
Serotonergic (5-HT)
Noradrenergic (NA/NE) 
Adrenergic
Cholinergic (ACh)
Histaminergic
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

what is a diffuse modulatory system

A

-Specific populations of neurons that project diffusely and modulate the activity of Glutamate and GABA neurons in their target areas.

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

what are the patterns of communication in the NS

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 dopamine neurons found

A

cell bodies in the midbrain

project into the forebrain

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

what systems are included in the dopaminergic system

A
  • Nigrostriatal system (75% of brain DA)
    (motor control)

Mesolimbic system

Mesocortical system
(behavioural effects)

Tuberohypophyseal system (endocrine control)

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

describe metabotropic receptors D(1-5)

Study These Flashcards
A

Dopamine (DA) receptors

Dopamine produces both EPSPs and IPSPs depending on the receptor subtype and coupled G proteins

D1-like (1 & 5) Gs - stimulate adenylyl cyclase
- stimulate phospholipase C
postsynaptic

D2-like (2, 3 & 4) 	Gi  	- inhibit adenylyl cyclase
				- open K+ channels
				- close Ca2+ channels
			postsynaptic
			presynaptic autoreceptors (D3)

Balance of these systems
maintains dopaminergic
tone

20
Q

describe the Nigrostriatal system

Study These Flashcards
A
  • cell bodies in the substantia nigra project to the striatum (caudate nucleus and putamen)
    Important part of the basal ganglia involved in movement.
21
Q

describe some dysfunctions associated with the nigrostriatal system

Study These Flashcards
A

Dysfunction:
Parkinson’s disease
destruction of DA projections from SN to basal ganglia
Huntington’s disease
destruction of DA target neurons in striatum

22
Q

what are some drugs that help with dysfunction in the Nigrostriatal system

Study These Flashcards
A

Drugs:

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

23
Q

describe the mesolimbic system

Study These Flashcards
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

24
Q

describe some dysfunctions associated with the mesolimbic system

Study These Flashcards
A

Dysfunction:

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

25
describe the drugs and their short and long term effects that stimulate the mesolimbic system
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
26
describe the Mesocortical system and its role
Mesocortical system – VTA projections to prefrontal cortex Role in functions such as working memory and planning.
27
describe the dysfunction in the Mesocortical system and some drugs used to treat them
Dysfunction: Schizophrenia ``` Drugs: 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
28
describe the serotonergic system
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
29
what dos the serotonergic system function in
mood sleep pain emotion appetite
30
describe the metabotropic serotonin receptors
Ionotropic 5-HT3 opens channel that fluxes Na+, K+, Ca2+ (excitatory) Metabotropic 5-HT1A Gi raphe, hippocampus 5-HT7 Gs thalamus, hypothalamus, amygdala 5-HT2A, B and C Gq cortex, hippocampus
31
describe the drugs that have an effect on the serotonergic system
1)Selective Serotonin Reuptake Inhibitors e.g.fluoxetine (Prozac) 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. 2)Methylenedioxymethamphetamine (MDMA) - ecstasy ``` causes serotonin (and norepinephrine) transporters to run in reverse increased release of serotonin and blocked reuptake ```
32
describe LSD
LSD – (Lysergic acid diethylamide) hallucinogen 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
33
describe the noradrenergic system
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
34
describe the adrenergic system
-Primarily in lateral tegmental area, projecting to thalamus and hypothalamus. Acts on a- and β- adrenergic receptors
35
describe the cholinergic system
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
36
look at slide 30 for ACh and NA in the PNS
how was it
37
describe some Disorders of the cholinergic system
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
38
describe the importance of AChesterase inhibitors
-Prolong action of acetylcholine at the synapse - Treatment for Alzheimer’s disease (e.g. physostigmine) - Treatment for Myasthenia gravis (neostigmine) Insecticides & Chemical warfare agents, e.g. “Sarin” Botox - prevents release of ACh at NMJ Latrotoxin - permanent release - depletes ACh at NMJ
39
what are the 2 types of ACh receptor
Two types of acetylcholine receptor Muscarinic - metabotropic Nicotinic – ionotropic Visceral motor system / sympathetic & parasympathetic preganglionic neurons
40
what is a muscarine
Muscarine (agonist of Muscarinic receptors – metabotropic | ) found in poisonous mushroom Amanita muscaria
41
what is a atropine
Atropine (antagonist of Muscarinic receptors – metabotropic | ) belladonna alkaloid extracted from deadly nightshade
42
describe some common muscarinic receptors and overall effects on neuron & whether on just post or presynaptic
M1 M3 via Gq to phospatidylinositol hydrolysis M5 (smooth muscles and glands) M2 M4 via Gi to inhibit cAMP (smooth and cardiac muscle) 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
43
describe muscle nicotinic receptor (structure, function, location, antagonist)
-2x a1, b, d and g subunits (neuromuscular junction NMJ) (Antagonist - curare (poison darts) - instant paralysis)
44
describe neuronal Muscle receptor (structure, and location)
Heteromeric combination of a3,4,5 and b2,3,4 or 6 Homomeric receptors a7, 8 or 9 a3b4 on autonomic ganglia a4b2 and a7 most common brain receptors Vary in their pharmacology, selectivity and kinetics and conductance Located pre and postsynaptically Presynaptic receptors - facilitate transmitter release (Na+ and Ca2+, depolarization and direct transmitter release)
45
describe the histaminergic system
Arousal & attention Reactivity of vestibular system Mediation of allergic responses Influence of brain blood flow 3 G-protein-coupled Rs

202 retake: theme 1 (21 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions