13. Fear & anxiety 1

Question 1

What is fear and why is it necessary? (Fear/anxiety B&B)

Answer 1

• Innate, evolutionary response

- When exposed to a threatening stimulus, freeze/flight/fight response is activated

Question 2

What are anxiety disorders a product of and how are they characterised? (Fear/anxiety B&B)

Answer 2

• Product of inappropriate fear responses
• Often very maladaptive
• Continuation of fear related behaviours

Question 3

What has findings shown from patients with panic disorders? (Fear/anxiety B&B)

Answer 3

They have lower than average benzodiazepine binding sites, suggesting a lack of GABA-A receptor activity

Question 4

What do anxiolytic dugs do? (Fear/anxiety B&B)

Answer 4

Increase GABA-A receptor activity

Question 5

What do anxiogenic drugs do? (Fear/anxiety B&B)

Answer 5

Decrease GABA-A receptor activity

Question 6

What happens in the presence of benzodiazepines? (Fear/anxiety B&B)

Answer 6

• GABA-A molecules more effective at opening Cl- channels
• Greater influx of Cl-
• Greater hyperpolarisation
• More inhibition

Question 7

Where are binding sites for benzodiazepines in α1? (Fear/anxiety B&B)

Answer 7

Everywhere, but very high in cortex

Question 8

Where are binding sites for benzodiazepines in α2? (Fear/anxiety B&B)

Answer 8

• Limbic structure
• Hippocampus
• Amygdala

Question 9

Where are binding sites for benzodiazepines in α3? (Fear/anxiety B&B)

Answer 9

• Brain stem

- Basal forebrain

Question 10

Where are binding sites for benzodiazepines in α5? (Fear/anxiety B&B)

Answer 10

• Hippocampus

- Spinal cord

Question 11

What is the elevated plus maze? (Fear/anxiety B&B)

Answer 11

• Shape of +

- Anxiety is measure by the degree to which the animal avoids the open arms (sticking to the centre)

Question 12

How does diazepam affect mice in the elevated plus maze? (Fear/anxiety B&B)

Answer 12

Increases the amount of time spent in the arms of the maze, suggesting a reduction in anxiety

Question 13

What is the conditioned emotional response task? (Fear/anxiety B&B)

Answer 13

• Mice trained to press one lever for food on a 120s interval
• Paired with bell sound and electric shock
• When bell sounds (even with no shock), mice produce anxiety

Question 14

What did GABA-A α2 subunit knockout mice show in the conditioned emotional response task compared to healthy controls? (Fear/anxiety B&B)

Answer 14

• No difference in lever pressing
• Lower suppression response in severity of shock
• No suppression when given BZ’s

Question 15

What is shown as a response to BZ’s and α3 mutant mice? (Fear/anxiety B&B)

Answer 15

Same sedation, anxiolytic, anticonvulsant and muscle relaxation effects