Effect of Drugs on the Transmission Process in the CNS

Question 1

A depressant is a drug that

Answer 1

slows down brain activity, e.g alcohol

Question 2

A hallucinogen

Answer 2

alters what we hear and see, e.g cannabis, LSD

Question 3

A painkiller blocks

Answer 3

nerve impulses, e.g aspirin, heroin

Question 4

A performance enhancer

Answer 4

improves muscle development, e.g anabolic steroids

Question 5

A stimulant increases

Answer 5

brain activity, e.g nicotine, caffine, ecstacy

Question 6

Recreational drugs are used in the absense of medical grounds for

Answer 6

personal enjoyment and they alter brain function

Question 7

Doctors call a drug addictive if it makes you dependent on the drug and withdrawal symptoms appear unless you take it and

Answer 7

you crave them, even after the withdrawal symptoms have disappeared

Question 8

Tolerance to drugs may develop which means

Answer 8

you need to take more of the drug to get the same effects as the brain adapts to the high levels of dopamine caused by the drug and regulates its own natural production of it therefore the baseline is lower

Question 9

Addictive drugs activate the brain’s reward system by increasing the release of the chemical dopamine from

Answer 9

neurons in the key areas of the brain

Question 10

The reward pathway connects

Answer 10

the ventral tegmental to the nucleas accumbens, the pathway is a collection of dopamine releasing neurons

Question 11

Cannabis will bind to cannibanoid receptors and block them which prevents the NT release from the presynaptic neuron sending the message to the postsynaptic neuron. Why does this affect memory?

Answer 11

The hippocampus has a lot of these receptors and is associated with memory, activity is prevented here

Question 12

Cannabis also stops specific neurons from

Answer 12

preventing dopamine production in the reward system, so there is excess dopamine

Question 13

Amphetamines force the release of dopamine, can block reuptake and in high doses can inhibit their breakdown by enzymes which result in

Answer 13

more dopamine in the synapse where it can act on receptors causing short term happiness

Question 14

Amphetamines are similar in structure to dopamine, so can enter the terminal button of the presynaptic neuron via

Answer 14

dopamine transporters as well as by diffusing through the neural membrane directly

Question 15

Once inside the presynaptic neuron, amphetamines force the dopamine molecules out of their

Answer 15

storage vesicles and expel them into the synaptic gap by making dopamine transporters work in reverse

Question 16

Nicotine works by mimicking the actions of a naturally occurring NT, acetylcholine, by docking with its special receptor molecules and so mimics its action. Also

Answer 16

it targets aspects of the dopamine pathway increasing the amount and transmission of dopamine by blocking the enzyme that breaks it down.

Question 17

Alcohol acts to inhibit neurotransmission by increasing the action of GABA (an inhibitory nt) which is why when people are drunk they seem sluggish, also

Answer 17

it seems that alcohol stops enzymes breaking down dopamine and it binds to receptors for seretonin which explains its initially pleasing affects

Question 18

Hard to study the mode of action of recreational drugs at the synpase although

Answer 18

brain scanning has helped but we still can’t get to the level of synaptic transmission

Question 19

There is credibility in the fact that drugs create more dopamine in the reward system and so give pleasure and also have a desensitising effect leading to tolerance and addiction as

Answer 19

observation of those who take drugs often at first experience great pleasure and then become addicted finding they need more to feel the pleasure again.

Question 20

Pickens and Thompson found that cocaine acted as a positive reinforcer for rats as when they pressed a lever they were given cocaine, they found

Answer 20

an increase in lever pressing as they had operantly conditioned the rats, the process suggests reliability to the explanation

Question 21

Alternative explanations for drug uses

Answer 21

OC, CC, SLT

Question 22

There is complexity in how transmission works in the brain that is hard to capture, e.g

Answer 22

there are multiple reward pathways in the reward system and more than one brain region involved therefore having one explanation for the mode of action is simplistic

Question 23

How does Olds and Milner support?

Answer 23

Put electrodes were put in rats brains they found when given electrical brain stimulation rats experienced ecstasy and would press a lever 2000 times an hour

Question 24

Besides the hippocampus, where else do cannibanoid receptors prevent the release of NTs and the passing of messages and what effect does this have?

Answer 24

In the cerebral cortex which affects concentration and perceptions and so gives an altered perspective of time and space.

Question 25

How does caffine work in the brain?

Answer 25

It increases the firing of dopaminergic neurons leading to feelings of pleasure