L12 - socially used and abused drugs

Question 1

how do social drugs evoke pleasure

Answer 1

activate dopaminergic reward pathways in brain

Question 2

where is the dopaminergic reward pathway

Answer 2

runs from the vetral tegmental area (VTA) to nucleus accumbens (NA)

Question 3

what is the direct activation of the reward pathway

Answer 3

VTA sends direct signals to Nucleus accumbens causing dopamine release

drugs can cause these signals to activate

Question 4

what is the indirect activation of the reward pathway

Answer 4

the reward pathway is under inhibition control

so drugs that inhibit this inhibition will activate the pathway

Question 5

what drugs can cause direct activation of the dopaminergic reward pathway

Answer 5

nicotine and ecstasy

Question 6

what drugs can cause indirect activation of the dopaminergic reward pathway

Answer 6

cannabis

Question 7

what is found in cigarettes

Answer 7

nicotine
arsenic
methanol
DDT

Question 8

effect of nicotine in the periphery

Answer 8

agonist at NAChRs

1. excite ANS ganglia - cause A release from medulla
2. slowed HR
3. vasoconstriction
4. increased BP

Question 9

effect of nicotine in CNS

Answer 9

release of many transmitters eg

• dopamine
• ACh
• serotonin

Question 10

how much more sensitive are NAChR’s in brain than NAChR’s in muscle?

Answer 10

50x more sensitive in CNS

Question 11

how are cigarettes toxic?

Answer 11

1. produce CO that displaces O from Hb
2. nicotine is vasoconstrictor and causes platelet aggregation
3. contains tar and irritants (carcinogenic)

Question 12

what is the effect of nicotine on expression of NAChR’s?

Answer 12

increased exposure to nicotine causes increased expression of NAChR’s

Question 13

where does heroin come from

Answer 13

opium poppy - synthesised from morphine - twice as potent

Question 14

what happens to heroin in the body

Answer 14

crosses BBB and is converted into morphine

Question 15

what receptors does heroin bind to and where are they located

Answer 15

opiate receptors in reward/pleasure areas (VTA and NA)

Question 16

effects of heroin

Answer 16

euphoria

addiction

Question 17

describe the acute toxicity of heroin

Answer 17

mild respiratory depression

Question 18

describe the chronic toxicity of heroin

Answer 18

severe respiratory depression
extreme sedation (confusion, anxiety)
respiratory failure

Question 19

effects of ecstasy

Answer 19

psychoactive stimulant
empathogenic
euphoria, arousal, endurance

Question 20

source of ecstasy?

Answer 20

synthetically made

Question 21

how does ecstasy produce its effect?

Answer 21

E displaces serotonin from vesicles
serotonin leaks out into cleft
E also blocks Serotonin reuptake pump
secondary rise in NA and A

Question 22

describe acute toxicity of ecstasy

Answer 22

1. hyperthermia (high temp) due to increased NA and metabolism and inability to regulate it
2. hyponatraemia (reduced blood NA+) due to sweat and drinking too much
3. exhaustion, irritability, low mood

Question 23

what is hyponatraemia

Answer 23

low blood Na+

Question 24

describe chronic toxicity of ecstasy

Answer 24

depression/anxiety

memory impairment

Question 25

why is it difficult to asses drug toxicity

Answer 25

1. people lie about drugs taken / how much

2. purity of drugs varies

Question 26

how was rationale scale of drug safety made

Answer 26

a graph of dependence on drug and toxicity (physical harm)