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Flashcards in Sleep Deck (29):
0

What are the stages of sleep?

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

1

How often does the sleep cycle occur each night?

4-5 times
Subsequent cycles decreased slow wave, increase rem

2

Why are minor awakenings in sleep cycle important?

Prevents nerve compression
Prevents circulatory pooling
Looks for threats

3

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

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

4

Describe the ascending reticular activating system

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

5

Describe the role of ventrolateral pre-optic area

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

6

Describe role of superchiasmic nucleus

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

7

Describe the orexin/hypocretin system

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

8

Discuss narcolepsy

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

9

Discuss pontine tegmentum

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

10

What determines sleep?

Homeostatic controls
Sleep modulating substances
Adenosine
Circadian rhythms

11

How do homeostatic control sleep?

Poorly understood
Inversely correlates w/ amount of prior slow wave sleep

12

Name sleep modulating substances

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

13

Role of adenosine

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

Adenosine r knockout mouse showed adenosine does not induce sleep alone

28

Circadian rhythms

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

29

Insomnia

Difficulty initiating and maintaining sleep

30

Hypersomnia

Sleep longer during day and have greater propensity to fall asleep

31

Sleep apnea

Nasopharyngeal collapse during sleep, snoring
Causes cardiac and pulmonary arrhythmias

32

Benzodiazepines

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

33

Triazolam

Benzodiazepine
Short half life promotes onset of sleep
Rebound insomnia

34

Flurazepam

Long half life interfers with day time activity
Benzo

35

Estazolam

Benzo
Some daytime sedation

36

Tenazepam

Benzo
Good but daytime sedation

37

Zolpidem

Not benzo but acts on same site

38

Barbituates

Activate receptors directly, in absence of gaba channel open longer

39

Sodium oxybate

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

40

Antidepressant

Trazadone and mirtazipine

Treat sleep

41

Melatonin

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

42

Ramelton

Melatonin r agonist