PCL200 Week 5: Drugs for Sleep

sleep

cyclical behaviour of reversible unconsciousness and immobility

depressant

drug that reduces neuron activity and arousal

hypnotic

drug that induces sleep

stimulant

drug that promotes wakefulness and arousal via increasing neuron activity

methods of measuring sleep

• electroencephalogram

• electromyogram

electroencephalogram

measures electrical activity of the cortex

• can pick up the sum of neurons firing at a period of time

electromyogram

measures electrical activity of muscles

EEG sum

irregular waves and no large peaks/valleys

• waves that form fast

EMG sum

peaks, valleys, and high wave forms that are slow

ways stages of sleep are measured

• muscle tone

• HR

• BR

• body temp

stages of sleep

1. awake

2. N1

3. N2

4. N3

5. REM

features of awakeness

• irregular pattern of high frequency and low amplitude electrical activity

• alpha activity predominates

• beta has low power and only occurs during lots of focus and attention

features of N1 stage

• transition between awake and sleeping

• light sleep

• normal breathing and HR

• VERY brief

features of N2 stage

• sleep spindles, k complexes, and SOME delta waves

• slow breathing and HR

• body temp. drops

features of N3 stage

• deep sleep

• long stretches of delta waves

features of REM sleep

• EEG pattern is similar to patterns of awakeness

• skeletal muscles are paralyzed

• breathing rate is faster and more shallow

features of the sleep cycle

• approx. 90 minutes

• majority is NREM and REM

• REM occurs usually in the morning

average cycles of newborns

• 16hrs/day

• 8 hrs of REM

average sleep cycles of someone in the 20’s

• 8hrs/day

• 2 hrs of REM

average sleep cycles of someone in the 80’s

• 6.5hrs/day

• 45 min of REM

reasons we sleep

• maintain cognitive and emotional systems

• reduce the risk of disease

• avoid fatal familial insomnia

• maintain physiological systems (homeostasis)

fatal familial insomnia

• neurodegenerative disease that affects the thalamus and other brain regions

• mutation in PRNP gene

• death occurs 6-36 months after onset

• can not be treated by hypnotics

what occurs when NREM is prevented

causes sleep pressure

sleep pressure

feeling sleepy the next day, causing a longer period of NREM sleep that night to compensate

what occurs when REM is prevented

impairs memory consolidation and retrieval

physiological functions of NREM

• clear by-products of metabolic activity via the glymphatic system

physiological function of REM

• consolidates memories and removes slow-wave sleep

• brings synapses to baseline

• determines what is preserved and how it is stored

REM dreams

more vivid, story-like, and are remembered

• usually nightmares

NREM dreams

happy dreams

neurons that promote wakefulness

• orexin

• dopamine

• serotonin

• norepinephrine

• histamine

receptor that induces sleep

GABA receptor

effects of low dose benzodiazepines

inhibits inhibitors and allows dopamine neurons to fire, causing euphoria

effects of high dose benzodiazepines

inhibit both GABA and dopamine, causing low arousal

effects of barbiturates

increases GABA

location of sleep area in the brain

pre-optic

location of neurons that keep you awake

mid-brain

effects of regular dose benzodiazepines

increases GABA signaling

• NOT a competitor to neurotransmitters, BUT an amplifier

ramelteon

pharmacotherapy for insomnia that is a melatonin receptor agonist (MLT1 and MLT2)

effects of ramelteon

• decreases body temperature

• decreases latency of sleep onset

• does not cause tolerance, dependance, or addiction

which is safer, benzos or barbiturates?

benzos

• less likely to cause lethal overdose

• has a drug that can counteract overdose (flumazenil)

cause of anxiolytic effects

quieting neurons in the amygdala

cause of therapeutic effects that promote sleep

quieting effects of neurons on the reticular activating system, thalamus, and the cortex

unwanted side-effects of benzos

• amnesia

• cognitive impairment

• motor impairment

• “hangover” feeling in the morning

• stomach issues

• highly addictive

z-class drugs (zolpidem)

• bind to a diff spot on GABA than benzos

• causes less daytime sleepiness and addiction

• causes parasomnia

parasomnia

doing unusual things when asleep (eg. sleep walking)

anterograde

when a person has no memory of the events caused by parasomnia