Affective Disorder Drugs

Question 1

Lithium is used for the treatment of a bipolar disorder and is generally used as an adjunctive to another anti-depressant medication. For example if a patient is bipolar 1 and already taking an anti-depressant but is having a manic episode, meaning they have increased neuronal activity, lithium can be prescribed to accentuate the effects of the anti-depressant. How does lithium accentuate anti-depressants?

Answer 1

• inhibits Gaq pathway
• lithium inhibits IMPase by displacing Mg2+
• IMPase creates free inositol
• inositol then creates PIP2 which is crucial for Gaq pathway
• no Gaq pathway means no release of Ca2+ and no release of neurotransmitters in to synaptic cleft

Question 2

There are a number of mechanisms that have been identified as to what causes depression. One theory is the monoamine hypothesis, which states that there is an imbalance between dopamine, serotonin and noradrenaline. Amitriptyline is a tricyclic anti-depressant medication. How does this drug treat depression?

Answer 2

• increases levels of serotonin and noradrenaline

Question 3

There are a number of mechanisms that have been identified as to what causes depression. One theory is the monoamine hypothesis, which states that there is an imbalance between dopamine, serotonin and noradrenaline. Amitriptyline is a tricyclic anti-depressant medication. Amitriptyline is able to increases levels of serotonin and noradrenaline. What is the mechanism of action of this drug?

Answer 3

• binds and inhibits the SERT (serotonin) transporter
• binds and inhibits the NET (noradrenalin) transporter
• keeps more serotonin and noradrenalin in synaptic cleft, increasing change of binding to post synaptic receptors

Question 4

There are a number of mechanisms that have been identified as to what causes depression. One theory is the monoamine hypothesis, which states that there is an imbalance between dopamine, serotonin and noradrenaline. Citalopram is a selective serotonin re-uptake inhibitor anti-depressant medication that is able to increase serotonin levels and relieve depression. What is the mechanism of action of Citalopram?

Answer 4

• able to bind and inhibit the serotonin re-uptake transports (SERTs)
• keeps serotonin in the synaptic cleft and action potentials firing in the post synapse