Alcohol Flashcards
(20 cards)
Alcohol is a CNS depressant, what does this mean?
has an overall inhibitory effect on neural activity and arousal
is alcohol quickly absorbed into the blood?
yes
alcohol has dose dependent effects, what happens at:
- 0.5 g/l
- 0.8 g/l
- 1.5 g/l
0.5 = anxiolytic, social lubricant
0.8 = impaired motor and cognitive function
1.5 = ataxia, blackouts
what is ataxia
staggering or slurred speech
what is a lethal blood concentration of alcohol
3-4 g/l
what is alcohols effect on dopamine
release
what does increased dopamine signal
increased activity of the mesolimbic dopaminergic pathway - positive reinforcement, motivation, reward anticipation
what does acute alcohol do to GABA
enhanced GABA inhibition = anxiolytic effects
what does acute alcohol do to glutamate, how?
reduces glutamatergic activity
- NMDA receptor antagonist
what type of memory is unaffected by alcohol consumption
implicit
how does alcohol affect memory
suppresses the firing of hippocampal place cells
how does neurotoxicity arise? in the example of glutamatergic neurons
alcohol reduces glutamatergic activity
the neuroadaptive response is to upgrade NMDA receptors
cessation of drinking causes NMDA receptor overactivity
this causes a large calcium influx into cells which causes hyper excitability and cell death.
how does alcohol dependency arise
compulsion to seek and take the drug
loss of control in limiting intake
negative emotions when access to the drug is denied
why is addiction quick in alcohol?
because it reaches the brain fast = immediate high
how does reinforcement mediate addiction
liking is associated with wanting
- learned association between anticipation and positive reinforcement
- chronic use leads to reinforced wanting
- wanting turns to craving behaviour
what is the role of mesolimbic dopaminergic system in addiction
becomes hyper-responsive
- drug cues trigger craving and increased salience
- increased motivation for alcohol seeking behaviour
what happens to receptors in chronic alcohol use
NMDA receptors become hypersensitive to glutamate
GABAergic receptors become desensitised
how does tolerance arise?
the impairing effects are reduced which has reinforcing properties = reduced pleasure
means that higher doses are needed to produce the same effects
how are the withdrawal effects caused?
reduced synaptic GABA activity lowers inhibition of the neuron
this creates anxiety behaviours and hyper excitability
what are the late stages of alcohol dependence
significant reduction in the volume of brain regions - prolonger periods of abstinent can lead to recovery
- this leads to cognitive deficits
