explanation for nicotine: brain neurochemisty

Question 1

define neurochemistry

Answer 1

Relating to chemicals in the brain that regulate biological and psychological functioning.

Question 2

one example of neurochemistry

Answer 2

dopamine

Question 3

define dopamine

Answer 3

A neurotransmitter
has an excitatory effect
associated with the sensation of pleasure

Question 4

what did dani and Heinemann look at

Answer 4

dopamine in their desensitisation hypothesis of nicotine addiction

Question 5

what is Acetylcholine (ACh)

Answer 5

key neurotransmitter in the central nervous system

ACh receptors on the surfaces of many neurons.

Question 6

one subtype of Acetylcholine

Answer 6

nicotinic acetylcholine receptor (nAChR).

Question 7

what is nicotinic acetylcholine receptors activated by

Answer 7

ACh or nicotine

Question 8

how dose nicotine effect nicotinic acetylcholine receptor

Answer 8

nAChRs are stimulated and transmit dopamine.

then immediately shut down and temporarily cannot respond to neurotransmitters.

neuron desensitised leads to down regulation

Question 9

what is downregulation

Answer 9

a reduction in the number of active neurons because fewer of them are available.

Question 10

where are nAChRs concentrated

Answer 10

the ventral tegmental area (VTA) of the brain

Question 11

what happened when nAChRs are stimulated by nicotine

Answer 11

dopamine is transmitted along the mesolimbic pathway to the nucleus accumbens (NA)

triggers the release of more dopamine from the NA into the frontal cortex.

dopamine is also transmitted along the mesocortical pathway to be released directly into the frontal cortex.

Nicotine powerfully activates this system and results in pleasurable effects

Question 12

what are both the mesocortical pathway and the mesolimbic pathway apart of

Answer 12

the brains dopamine reward system.

Question 13

what happens when the pleasurable effect occurs due to nicotine

Answer 13

effects become associated with smoking through operant conditioning.

Question 14

What happens to nicotine in the body when a person stops smoking overnight?

Answer 14

nicotine disappears from the body.

Question 15

What happens to nAChRs when nicotine disappears from the body?

Answer 15

nAChRs become functional again, so dopamine neurons resensitise and more become available (upregulation).

Question 16

What happens during resensitisation?

Answer 16

nAChRs become overstimulated by ACh and are at their most sensitive.

(because there is no nicotine for them to bind with)

Question 17

Why do smokers describe the first cigarette of the day as the most enjoyable?

Answer 17

it strongly reactivates the dopamine reward system.

Question 18

what happenes when people keep having cigarette to avoid withdrawal.

Answer 18

a constant cycle of daytime downregulation and night-time upregulation

creates long-term desensitisation of nAChRs (i.e. dependence).

Question 19

what dose continuous exposure to nicotine cause

Answer 19

permanent changes to brain neurochemistry – a decrease in the number of active nAChRs.

Question 20

Why does tolerance develop in smokers?

Answer 20

the smoker needs more nicotine for the same effects.