Sleep

Question 0

How often does the sleep cycle occur each night?

Answer 0

4-5 times

Subsequent cycles decreased slow wave, increase rem

Question 1

What are the stages of sleep?

Answer 1

Awake
Drowsy
NREM:
50% theta rhythms
Theta with burst k complexes and spindles
Slow wave/deep sleep, delta waves (synchrony)
REM
Low amplitude, desynchronised eeg
Looks like youre awake
Limbs relaxed

Question 2

Why are minor awakenings in sleep cycle important?

Answer 2

Prevents nerve compression
Prevents circulatory pooling
Looks for threats

Question 3

What are the sleep pathways/brain areas involved in sleep?

Answer 3

Ascending reticular activating system
Ventrolateral preoptic area
Superchiasmic nucleus
Orexin/hypocretin system
Pontine tegmentum

Question 4

Describe the ascending reticular activating system

Answer 4

Thalamus to cortex

Uses ne, 5ht, da and hist to INCREASE WAKEFULLNESS

Question 5

Describe the role of ventrolateral pre-optic area

Answer 5

Portion of the anterior hypothalamus
Active during nonREM
Releases gaba and galanin inhibiting neurones involved in wakefullness
Activated by 5ht and adenosine

Question 6

Describe role of superchiasmic nucleus

Answer 6

Controls circadian rhythms
Input from retina
Projections to hypothal nuc and pineal gland to control body temp and cortisol levels

Question 7

Describe the orexin/hypocretin system

Answer 7

Lateral hypothal
Orexin is a neuropeptide that binds gpcr
Involved in sleep, feeding behaviour, sexual activity
Promotes wakefullness, excites monoaminergic neurones of ARAS
Inhibited by vlpo neurones during nrem
Integrates external stimuli to determine wakefullness

Question 8

Discuss narcolepsy

Answer 8

Mutation in orexin receptor causes narcolepsy in dogs
Some narcoleptic people have orexin peptide deficiency

Abnormal transition between rem and nonrem at night and sleep wake cycle
Intrusive episodes of rem
Hallucination at onset of sleep

Question 9

Discuss pontine tegmentum

Answer 9

Drives rem
Contains drugs to turn rem on and off
Produces eye movement and muscle atonia

Question 10

What determines sleep?

Answer 10

Homeostatic controls
Sleep modulating substances
Adenosine
Circadian rhythms

Question 11

How do homeostatic control sleep?

Answer 11

Poorly understood

Inversely correlates w/ amount of prior slow wave sleep

Question 12

Name sleep modulating substances

Answer 12

Muramyl dipeptide
Interleukin-1
Delta-sleep inducing peptide
Prostaglandin p2
Tumour necrosis factor

Question 13

Role of adenosine

Answer 13

Increases during prolonged wakefullness
Decreased at awakening
Inhibits monominergic input to aras

Adenosine r knockout mouse showed adenosine does not induce sleep alone

Question 28

Circadian rhythms

Answer 28

Endogenously driven 24hr cycle of bioactivity
Helps organism cope w/ changes in environment
Controlled by scn neurones
Maintained by expression of period genes and cryptochrome genes
Protein products increase during waking hours
Scn neurones have photoreceptors

Question 29

Insomnia

Answer 29

Difficulty initiating and maintaining sleep

Question 30

Hypersomnia

Answer 30

Sleep longer during day and have greater propensity to fall asleep

Question 31

Sleep apnea

Answer 31

Nasopharyngeal collapse during sleep, snoring

Causes cardiac and pulmonary arrhythmias

Question 32

Benzodiazepines

Answer 32

Lower risk over overdose compared to barbs
Anxiolytic and promotes onset of sleep
Increase gabaa r affinity for endogenous gaba
Increases opening time of cl channel

Question 33

Triazolam

Answer 33

Benzodiazepine
Short half life promotes onset of sleep
Rebound insomnia

Question 34

Flurazepam

Answer 34

Long half life interfers with day time activity

Benzo

Question 35

Estazolam

Answer 35

Benzo

Some daytime sedation

Question 36

Tenazepam

Answer 36

Benzo

Good but daytime sedation

Question 37

Zolpidem

Answer 37

Not benzo but acts on same site

Question 38

Barbituates

Answer 38

Activate receptors directly, in absence of gaba channel open longer

Question 39

Sodium oxybate

Answer 39

Naturally occurring cns metabolite produced in hypothalamus and basal ganglia

Treatment for primary insomnia and narcolepsy
Date rape drug
Not sure of mechanism gabaa and b receptors

Question 40

Antidepressant

Answer 40

Trazadone and mirtazipine

Treat sleep

Question 41

Melatonin

Answer 41

Made in pineal gland from tryptophan and serotonin
Gi linked mt1 and mt2 receptors
Resets circadian clock
Associated with endocrine disturbances
Efficacy in non circadian insomnia unknown

Question 42

Ramelton

Answer 42

Melatonin r agonist