Recreational Drugs: Addiction And Neuroscience Flashcards
How are drugs used recreationally?
Rewarding effects of drugs create issues with dependence. Effect of drug diminishes after repeated use, so higher quantities of the drug is required to have the same effect = tolerance.
What is a definition of addictive behaviour?
Loss of control, and a separation of liking and wanting.
What neurotransmitter receptors are involved in different drugs?
- Nicotine = subtype of acetylcholine receptor.
- Alcohol = modulates GABA-A and GABA-B receptor.
- Opiates = opioid beta receptor.
- MDMA = serotonin 2A receptor and serotonin transporter.
- Cocaine = dopamine transporter.
- Amphetamine = releases dopamine.
- Barbiturates = modulates GABA-A receptor.
- Cannabis = cannabinoid CB1 receptor.
What is a place preference task?
Uses genetically manipulated animals. Have a chamber with two distinct parts (checked walls and pattered floor and plain side). In plain side object with drug, on patterned side inject with saline solution. Repeat sequence. When allow the animal to choose which side they want to be on spend more time in drug associated environment.
What are the effects of cocaine?
Cocaine blows the dopamine transporter, increasing levels of dopamine at the synapse. Also a local anaesthetic, resembling lidocaine (lidocaine blocks AP’s by blocking sodium channels). Has a behavioural effect.
What is the effect of amphetamines?
Has some clinical uses (ADHD and narcolepsy). At higher does used recreationally. Enhances dopamine release and reduces reputake. Can be used to treat binge eating.
How do psychostimulants affect the dopamine system?
Cocaine blocks the reuptake pump system (reuptake mechanism goes around the cycle and take the neurotransmitter back into the presunaptic terminal. Dopamine can therefore be reincorporated into vesicles and can be re-released). Amphetamines promote the release of dopamine. Their behavioural effects are similar.
What is the effect of cannabis?
Contains large amount of psychoactive compounds. Some have an effect which are opposed to the effects of THC (rewarding effect of cannabis).
What are synthetic cannabinoids?
Full agonist = produces maximal stimulation of the target at higher doses (high efficacy). Partial agonist = produces a smaller effect (moderate efficacy). Agonists reduces the effect of partial and full agonists.
What is the effect of an agonist?
Agonist drugs essentially have no effect. Different drugs have 2 effects at the receptor: can stimulate post-synaptic mechanism (high efficacy), low efficacy drug likely to be an agonist. Also depends of infinity of receptor (how well it binds to neurotransmitters). Antagonist binds to receptor but doesn’t activate mechanism = useful in treating bad effects of drugs e.g. breathing failure.
What is the link between dopamine and reward?
Many drugs lead to activation of brain dopamine systems, either directly or indirectly. These drugs are rewarding.
What are the brain circuits for drug reward?
Within the brain have ventral tegmental area: have cell bodies that use dopamine as their neurotransmitter. Activation of this system can demonstrate effects of many drugs.
What happens to the prefrontal and temporal cortex when you take cocaine?
Study asked cocaine abusers to rate craving for cocaine while observing images of either neutral or cocaine-associated objects. Craving increased when looking at cocaine-associated cues, and blood flow to prefrontal cortex and medial temporal cortex increased. Also activated ventral striatum and other basal ganglia structures.
How can you treat drug addiction?
(a) substitute drug with one that has less rewarding properties.
(b) block the effects on the rewarding drug with an antagonist.
(c) use a behavioural strategy(e.g. CBT)
