Drug Dependence [9]

Question 1

What neurones are involved in the reward pathway

Answer 1

The mesolimbic dopaminergic neurones

Question 2

What contributes to the reward feeling

Answer 2

Increase release or prevent uptake of DA in nucleus accumbens

Question 3

There is evidence for a separate opioid-mediated pathways involving

Answer 3

5-HT and GABA

Question 4

What is habituation

Answer 4

Withdrawal affects

Question 5

What is the habituation mechanisms

Answer 5

Increased adenylate cyclase activity to compensate for acute inhibitory effect on cAMP

Question 6

In habituation - what other pathways are increased

Answer 6

G-proteins & protein kinases
Increased activity of ion channels
Cells are more excitable

Question 7

How is smoking addictive

Answer 7

Activation of nicotinic Ach receptors
Channel opening
Neuronal excitation

Question 8

What is the difference in consequence with small / large doses of nicotine

Answer 8

Small doses - arousal
Large doses - the reverse

Question 9

How do peripheral side effects of nicotine occur

Answer 9

Stimulation of autonomic ganglia & peripheral sensory receptors mainly in heart + lung
Causes autonomic responses
- tachycardia, increased GI output, increased arterial pressure etc

Question 10

How does tolerance of nicotine arise

Answer 10

Desensitisation of nicotinic Ach receptors

Question 11

How does dependence of nicotine arise

Answer 11

It causes excitation of the mesolimbic pathway & increased DA release in nucleus accumbens

Question 12

What are the physical withdrawal symptoms of nicotine

Answer 12

Irritability, aggressiveness, sleep disturbance
- these can persist for 2-3 weeks but cravings last much longer

Question 13

Harmful effects of smoking

Answer 13

Cancer
Coronary heart disease
Chronic bronchitis

Question 14

3 treatments for smoking addiction

Answer 14

Nicotine replacement therapy
Varenicline
Clonidine

Question 15

What membrane ion channel / receptors does ethanol increase

Answer 15

GABA
Nicotinic Ach
5-HT3

Question 16

What membrane ion channel / receptors does ethanol decrease

Answer 16

Ca2+
Glutamate
NMDA

Question 17

Ethanol has depressant action true/false

Answer 17

True

Question 18

What effect does ethanol have on dopamine

Answer 18

Enhanced dopamine release in reward pathway
- DA released from ventral tegmental area and nucleus accumbens

Question 19

Effects of acute ethanol intoxication

Answer 19

Slurred speech
Motor incoordination
Increased confidence

Question 20

Effects of higher levels of intoxication

Answer 20

Euphoria & melancholy
Aggression & submission
Driving risk

Question 21

What neurological syndrome can ethanol cause

Answer 21

Dementia
Partly due to thiamine deficiency

Question 22

What is the cardiovascular effect of ethanol

Answer 22

Heat loss

Question 23

What is the gastric mucosa effects of ethanol

Answer 23

Chronic gastritis

Question 24

What is the diuresis effects of ethanol

Answer 24

Inhibition of ADH secretion

Question 25

What is ethanols effect on the liver

Answer 25

Increased fat accumulation Hepatitis Hepatic necrosis & fibrosis

Question 26

Why does ethanol cause fat accumulation in the liver

Answer 26

Release of fatty acids from adipose tissue Impaired fatty acid oxidation due to metabolic loss by ethanol

Question 27

What is used in aversion therapy for alcohol abuse

Answer 27

Disulfiram Has a severe reaction with ethanol by preventing conversion of acetaldehyde to acetic acid (build up of acetaldehyde) Causes flushing, panic, tachycardia

Question 28

What are the beneficial effects of ethanol

Answer 28

Protective against atheroma formation Increased plasma HDL