Pharmacology

Question 1

What is the action of benzodiazepines (e.g. diazepam)?

Are they an allosteric or orthosteric modulator

Answer 1

Benzodiazepines enhance GABA receptor activity.
They act at the GABA-A receptor which is a ligand-gated ion channel for Cl-.
(They do not affect the GABA B receptor which is G protein-coupled).
GABA is an inhibitory neurotransmitter, therefore leading to anxiolytic activity and sedation.
Are allosteric modulators: bind at different site that leads to structural changes in the receptor. This modifies the receptor’s response to the ligand.

Question 2

What are some effects of increasing dopamine levels?

Answer 2

improve motor function, behaviour changes and dependence

Question 3

Which anaesthetics are commonly given by the intravenous route? Which ones are inhaled?

Answer 3

IV: propofol, thiopentane
Inhaled: the ‘fluranes’: desflurane, sevoflurane, isoflurane

Question 4

What does carbimazole treat and what is its action?

What is the action of propylthiouracil?

Answer 4

Treats hyperthyroidism (Grave’s disease)
Action: Inhibits thyroid peroxidase (which adds iodine to thyroglobulin to make T3 triiodthyroxine and T4 thyroxine)
Another drug, Propylthiouracil – also inhibits T4 to T3 conversion. T3 is more potent but less abundant (10%).