Pharmacology of Antidepressants & Mood Stabilisers

Question 1

What are the 3 main monoamine neurotransmitters and what is the monoamine hypothesis ?

Answer 1

Depression results from a functional deficit of monoamine transmitters in particular serotonin (5-HT) and noradrenaline (note this is too simplistic

Question 2

What is the mechanism of action of monoamine oxidase inhibitors ?

Answer 2

The irreversibly or reversibly inhibit monoamine oxidase an enzyme (present in most tissues) which catalyses the oxidation and inactivation of monoamine neurotransmitters.reversibly or reverisbly inhibit

==> increasing the levels of monoamine neurotransmitters

Question 3

What is the mechanism of action of tricyclic anti-depressants ?

Answer 3

Block the reuptake of monoamines (mainly noradrenaline and 5-HT) into presynaptic terminals ==> increasing there levels

Question 4

What is the mechanism of action of SSRI’s?

Answer 4

Selectively inhibit reuptake of serotonin (5-HT) from the synaptic cleft.==> increasing serotonin levels

Question 5

What is the mechanism of action of SNRI’s?

Answer 5

Block the reuptake of monoamines (noradrenaline and 5-HT) into presynaptic terminals.

Question 6

What is the mechanism of action of mirtazapine (also called Noradrenergic and Specific Serotonergic Antidepressant (NaSSA) or atypical anti-depressant)?

Answer 6

blocks a2, 5-HT2 & 5-HT3 ==> increasing noradrenaline and serotonin levels are these receptors correspond to these drugs

Question 7

What is the mechanism of action of lithium carbonate ?

Answer 7

may block phosphatidylinositol pathway (second messenger system) or inhibit Glycogen Synthase Kinase 3β

Question 8

What is the mechanism of action of atypical anti-psychotics used as mood stabalisers ?

Answer 8

Dopamine antagonism + 5-HT antagonism