Insomnia Flashcards
What is the spectrum of sleep-wake disorders?
Spectrum is from deficient arousal to excessive arousal
Which neurotransmitters are incolved in sleep/wakefulness
- Histamine
- Dopamine
- Norepinepherine
- Serotonin
- Acetylcholine
The collection of NT circuits related to arousal known as?
how does it regulate arousal?
the ascending reticular activating system
regulates arousal in a continuous way
What is the sleep-wake switch? how does it regular sleep?
it’s a hypothalamic cicuits that relate to sleep in a discontinuous way
-> there is an ‘on’ switch that promotes wakefulness and an ‘off’ switch that promotes sleep
How is the sleep-wake switch regulated?
Orexin-containing neurons of the lateral hypothalamus (LAT)
- stabalize and promote wakefulness (through release of NT orexin)
Melatonin-sensitive neurons of the suprachiasmatic nucleus (SCN)
-> used as an internal clock that incoporates circadian input in response to light/dark
Melatonin levels increase and when they reach a threshold the switch turns switch off (promotes sleep) - homeostatic sleep drive
Melatonin levels decrease and when they reach a lower threshold the switch is turned on (promotes wakefulness) circadian wake drive
What are the 2 systems that regulate sleep
- the ascending reticular activating system
2. Sleep-wake switch (binary)
How is histamine involved in regulating sleep?
H1 receptors are those involved in wakefulness through a G-protein-linked secondary messenger
• Blocking H1 receptors leads to sedation, drowsiness, or sleep
• H3 receptors also in brain – autoreceptors that stop histamine release (blocking an autoreceptor would promote wakefulness)
When are Benzodiazepenes used to treat sleep?
– Immediate response needed
– Non-pharmacologic measures do not work or Z-drugs
– When other psychiatric and medical illnesses are present – Short-term use
What is the definition of insomnia
Difficulty falling asleep, maintaining sleep, arising, or not feeling rested despite a sufficient opportunity to sleep
What is the mechanism of action of the Z drugs
Positive allosteric (binds to site other than the GABA binding site) modulators of GABAa but different site as benzos
Different drugs affect different receptor subtypes of GABAa – alpha 1 (sedation),
But doesn’t act on alpha 2 (anxiolytic, muscle relaxant), alpha 3 (anxiolytic, muscle relaxant), alpha 5 (hippocampus, cognition)
What do Melatonergic hypnotics do?
what is a drawback of these and metatonin
bind to the site that melatonin does
good for initiating sleep but won’t help you stay asleep
What is trazadone?
what % of insomnia presctiptions does it account for?
a serotonergic hypnotic (blockage of SERT, but also antaganizes 5HT2a AND is an antihistamine and alpha 1 antagonist (NE)
50% of all prescriptions
Should quetiapine be used for sleep?
not really, some argue at low doses ok, but not good first line
