Problem 1 When is a drug a drug? Flashcards
What is a drug?
A substance that comes from outside the body, crosses the blood/brain barrier and has an effect similar to our natural neurotransmitters
Opioids
o Target endorphin receptors and creating a dreamy sense of well-being
o used as painkiller (physical as well as psychological pain)
Stimulants (upper)
o Release noradrenaline and dopamine making you feel alert and full of energy
Depressants (downer)
o Activate GABA receptors
o They are useful for decreasing anxiety, relieving insomnia and pain, reducing convulsions, and relaxing muscles in spasm
Psychedelics
o Have effects on serotonin receptors but where they engage else where is not really known
Difference between dependence and addiction
The difference is that that you have the craving with an addiction. (Addiction is the last stage of dependence)
Pull factors
Pleasure, powerful memories, reducing suffering, new meanings
Push factors
Impulsivity, Compulsion, withdraw
Dopamine
is involved in drive and desire and perhaps (pretty sure that it is like this) reward (important for addiction acts at the reward centre of the brain the nucleus accumbens)
Endorphines
Give peace and pleasure, reduce suffering and numbs pain
GABA & Glutamate
regulate memory
Serotonin
may be involved in attributing meaning to experience
Noradrenalin
related to impulsivity and compulsivity
The addicted personality
o When mother used drugs during pregnancy
o Traumas encourage opiate use
o Impulsivity
o Compulsivity (are less likely to start but when its harder to stop)
o Anxiety (relief of these feelings)
o Gender: men are more likely to get addicted because they tend to more sensation seeking
Effects of alcohol
o Reduces anxiety
o Concentrations >50 ml/dl: produce ataxia, inattention and slowed reaction times
o Concentrations >150 ml/dl: amnestic
o Concentrations above 300 ml/dl: death from respiratory depression can occur
Effects of tabaco
o Highly addictive
o Increases the risk of lung cancer and can cause chronic bronchitis, emphysema and asthma as well as heart problems cardiovascular disease and stroke
o Nicotine: has anti-psychotic and cognition-impairing properties
o No loss of tangibles and relationships
o Medium international damage caused by deforestation fertilisers and farmers who are exploited
o Social benefits: Smokers tend to have a strong sense of group identity and create social bonds by while consuming cigarettes
Tabaco and Neurotransmitter
o Smoke contains substances that block the important brain enzyme monoamine oxidase (MAO)
o Monoamine oxidase: breaks down dopamine so if blocked, the level of dopamine increases
o is delivered to the brain nearly as fast as an injection
o tabaco binds to acetylcholine receptors
Alcohol and neurotransmitter
o Releases endorphins noradrenaline and dopamine and endogenous opioid
Receptors involved in reinforcement actions of alcohol
mu and delta receptors (opioid receptors)
GABA (alcohol)
GABA a receptor: alcohol increases the ability of GABA a receptor to open chloride channel but only for some sorts of GABA a receptor. (if gamma-2 unit of the GABA a receptor includes the amino acid serine, alcohol potentiate GABA)
GABA enhancing actions of alcohol are found at low concentrations (<100 mg/dl)
At higher concentrations alcohol has a direct action on the receptor, causing opening of the chloride channel that is GABA independent (>250 mg/dl)
Glutamate (alcohol)
Key receptor: NMDA receptor → sits in the cell membrane and regulates calcium passage
Alcohol acts as a blocker of the NMDA channel, opposing the effects of glutamate (>100 ml/dl)
Contributes to the causation by alcohol of amnesia and other cerebral depressant effects
• Hedonic homeostatic dysregulation
1 pre occupation and anticipation
o Dopamine and endorphin are high and stress is too
2Positive reinforcement: (binge intoxication)
o Dopamine and endorphin are high stress is gone
3Withdraw negative affect
o Neurotransmitter go low because they were to high and the stress goes up → craving
