W20-L5: Transmitters and Receptors

Question 1

Where can drugs effect the CNS?

Answer 1

They can effect action potentials, synthesis of NT, release of NT, re-uptake, breakdown and actions at receptor

Question 2

Difference between cocaine and amphetamine

Answer 2

Cocaine blocks re-uptake

Amphetamine causes non-exocytotic release

Question 3

What are two treatment options for epilepsy?

Answer 3

A. Reduce excitatory input (Phenytoin)

B. Enhance inhibitory input (Benzodiazepines)

Question 4

What are benzodiazepines used in?

Answer 4

–  Epilepsy
–  Anxiety
–  Sleep disorders
–  Premedication
•  Sedation for medical
procedures
–  Acute alcohol withdrawal

Question 5

What is the problem with barbiturates?

Answer 5

They have a low therapeutic index and are highly addictive

Question 6

How do benzodiazepines work?

Answer 6

Interact with GABA A receptors only, increases the frequency of Cl- channel opening

Question 7

What type of modulation do benzodiazepines work by?

Answer 7

Allosteric modulation

Question 8

Why can you not die from an overdose of a single benzodiazepines?

Answer 8

There is a ceiling in the amount of activation a receptor channel can open which is below death

Question 9

What are some advantages of allosteric modulators?

Answer 9

• Ceiling of effect of inhibitors – increased therapeutic window
• Positive modulation of endogenous agonist effect rather than continuous effect of exogenous agonist
– physiological regulation continues
• Great receptor subtype selectivity possible

Question 10

What are some problems with benzodiazepines?

Answer 10

• Tolerance
– Gradual escalation of dose needed
• Dependence
– Signs of physical & psychological withdrawal
• Nausea, tremor, also anxiety, depression, insomnia – Gradual dose reduction

Question 11

What is potency?

Answer 11

Relative position of the dose-effect curve along the dose axis

Question 12

When is the only case in which low potency is a disadvantage?

Answer 12

if the dose is so large that it is awkward to administer

Question 13

What is efficacy?

Answer 13

The ability of a drug to do the right thing

Question 14

Barbiturates V Benzodiazpines

Answer 14

Both potentiate the effect of GABA
• Benzodiazepines increase the frequency of the chloride ion channel opening at the GABAA receptor (increases GABA potency)
• Barbiturates produce their pharmacological effects by increasing the duration of chloride ion channel opening at the GABAA receptor (increase GABA efficacy)