Explanations for nicotine addiction: brain neurochemistry AD

Question 1

Neurochemistry

Answer 1

relating to chemicals in the brain that regulate biological and psychological functioning

Question 2

Dopamine

Answer 2

a neurotransmitter that generally has an excitatory effect and is associated with the sensation of pleasure.

Question 3

Dani and Heinemann

Answer 3

focussed on dopamine in their desensitisation hypothesis of nicotine addiction and the neurotransmitter acetylcholine.

Question 4

nAChRs

Answer 4

n=nicotine
Ach= acetylcholine
Rs= receptors

Question 5

Acetylcholine ACh plays a role in all nervous system activity, which means that….

Answer 5

they are on the surfaces of most neurons in the CNS.

Question 6

The subtype nicotinic acetylcholine receptors (nAChR) are activated by nicotine molecules and then transmits dopamine. This then……..

Answer 6

gets followed by shutdowns where the nAChR temporarily cannot respond to neurotransmitters.

Question 7

Where are nAChR concentrated?

Answer 7

the ventral tegmental area VTA of the brain

Question 8

What happens when nAChR are stimulated by nicotine?

Answer 8

dopamine is transmitted along the mesolimbic pathway to the nucleus accumbens NA, which triggers the release of more dopamine into the frontal cortex.
Simultaneously, dopamine is also transmitted along the mesocortical pathway to be released directly into the frontal cortex.

Question 9

what activates the brain dopamine reward system?

Answer 9

nicotine, results in pleasurable effects such as mild euphoria, increased alertness and reduction of anxiety.

Question 10

withdrawal

Answer 10

When someone abstains from smoking then
the nAChRs become functional again and dopamine neurons resensitise and more become available (upregulation).

During this time, the person will experience withdrawal symptoms.

Question 11

dependance and tolerance

Answer 11

Smoker avoids unpleasant physiological and psychological withdrawal by having another cigarette. This means that there is a constant cycle of daytime downregulation and night-time upregulation (from sleeping) creates long term desensitisation of nAChRs.

Question 12

What does continuous exposure of nAChR to nicotine cause?

Answer 12

permanent changes to the brain neurochemistry → a decrease in the number of active receptors

Question 13

tolerance

Answer 13

develops as a smoker has to smoke more to get the same effect.

Question 14

Research support -
Support from human research

strength

Answer 14

• McEvoy et al studied smoking behaviour in people with schizophrenia who were taking a antipsychotic drug
• This drug blocks dopamine receptors in the brain, reducing dopamine transmission
• So people taking the drug had increased levels of smoking presumably from self-medicating
  Supports the view that dopamine has a key role in the neurochemistry of nicotine addiction.

Question 15

counterpoint to RS -Counterpoint
Explanations of nicotine addiction that consider only the role of dopamine are limited

limitation

Answer 15

• Research increasingly shows complex interactions of several neurochemistry systems
• Watkins et al said these include neurotransmitter pathways and endogenous opioids
  Therefore the neurochemistry of nicotine addiction cannot be fully understood by just looking at dopamine.

Question 16

RWA -
Neurochemistry lends to new treatments

strength

Answer 16

• Nicotine replacement therapy NRT helps smokers quit
• NRT products like gum release a controlled dose of nicotine, which acts neurochemically by binding with nAChRs
• Satisfies cravings and reduces withdrawal symptoms
  Greater understanding of neurochemistry has led to an effective treatment for nicotine addiction.

Question 17

Withdrawal symptoms -
Does not fully explain withdrawal

limtiation

Answer 17

• According to the theory, withdrawal symptoms rely on the amount of nicotine in the body
• Gilbert challenges this as these factors are not strongly correlated
• He argues that withdrawal depends on environment and personality
  Withdrawal effects can be explained in other ways

Question 18

determinism - Shiffman and Paty 2006

Answer 18

This explanation is biologically deterministic, so nicotine addiction is inevitable in someone who has started smoking because of the chemicals in the brain. But some people smoke without becoming dependent on nicotine

Question 19

What are shutdowns?

Answer 19

This is when the neuron is desensitised, which leads to downregulation (a reduction in the number of active neurons because fewer of them are available)

Question 20

What do the pleasurable effects of nicotine causing the release of dopamine become associated with through operant conditioning?

Answer 20

smiling