L5 Pharmacology of Sleep Flashcards
What does ACh do in the ascending arousal system?
ACh from the LDT and PPT send signals to the thalamus to keep it active
Where are adenosine receptors in the brain?
They are located throughout the brain and block NT release (blockage of ACh = tiredness)
Many drugs interact with this process
What is the stimulant/sedation feedback loop?
Dependence on caffeine and nicotine in the morning to wake them up and have more throughout the day when the effects wear off
They then struggle to initiate/maintain sleep and rely on sedatives to help them get to sleep e.g. sleeping tablets and alcohol
What is the most widely used drug in the world?
Caffeine, and it comes in many forms
Coffee, chocolate, tea, fizzy drinks, energy drinks
Causes increased blood pressure, heart rate, increased anxiety via the ANS
How does caffeine work to promote wakefulness?
Caffeine’s molecular structure is very similar to adenosine so has the ability to bind to adenosine receptors as a competitive inhibitor
Adenosine is now no longer able to block cholinergic activity and therefore promotes wakefulness
If people rely on coffee in the long term, they may need to consume more to have the same benefits (tolerance)
What is caffeine’s affect on sleep?
It increases sleep onset latency, increases time spent in lighter stages of sleep, increases WASO, decreases in TST, decrease in sleep efficiency and an increase in day time dysfunction
Some studies show reduced REM sleep but it is dependent on duration and concentration of caffeine intake
Stimulating effects last for about 4 hours but stay in blood for longer as it metabolises slowly
People have different sensitivities due to metabolic rates
What happens with caffeine withdrawal?
Reduced sleep onset latency
Increased WASO
REM rebound
Increased TST - doesn’t necessarily mean good sleep quality
What mechanism does nicotine work through?
Addictive property of cigarettes
Nicotine also binds to nicotinic ACh receptors in the basal forebrain, activating them and producing excitation - increasing cholinergic activity and promoting wakefulness
Also releases dopamine activity as propagates to NAc, promoting wakefulness
What is nicotine’s effect on sleep?
Increased sleep onset latency, increased time spent in lighter stages of sleep, decreased SWS, decreased REM sleep, increased WASO, TST decreased
What happens with nicotine withdrawal?
Decreased sleep onset latency
Increased WASO
REM rebound
Increased TST
What did Colrain, Trindaer and Swan (2004) suggest about smoking cessation?
That cessation leads to SD, with sleepiness and dysphoria as side effects. This may result in smoking relapse to deal with these symptoms
How does alcohol work in the brain?
Potentially acts via increasing GABA activity and sedates the body
Other research predicts that it is involved with adenosine
Alcohol increases extracellular levels of adenosine, build up promotes sleepiness
Also alters synaptic functions of DA receptors in mesolimbic striatum causing increase in DA activity (Garcia & Salloum, 2015)
What happens in the night after alcohol consumption?
Individuals spend a lot of time in deep sleep in the early part of the night but this is just sedating yourself, it is not getting the natural biological sleep
Therefore all the benefits of SWS are not taking place
Alcohol metabolises quite quickly so wake up frequently during night, after sedative effects have worn off
Have a lot of REM sleep in second half
At low does alcohol reduces stage 3 NREM
Can worsen snoring and nightmare
What can be seen in alcohol withdrawal?
Increased sleep onset latency
Reduced SWS and increased REM rebound
Increased WASO
Reduced TST and efficiency (fragmented)
Lot of people go back to drinking so they actually sleep
How do we study cannabis’ effect on sleep?
Have to find people who are already actively using cannabis but these people often have additional addictive problems
Creates problems with quality of data
Also 60 different cannabinoids and a variety of ways to consume it - effects how it sits in your blood
