Pharmacology of anti-depressant drugs and mood stabilisers Flashcards
Name a MOAi
Iproniazid
What do appetitive/ approach systems do?
Function to mediate seeking and approach behaviours (including pleasure)
What do aversive/defensive systems do?
Function to promote survival in the event of threat (fear/pain)
What is the dorsal striatum responsible for?
Movement
What is the amygdala responsible for?
Conditioning/learning
What is the anterior cingulate responsible for?
The anterior cingulate cortex is responsible for reward anticipation, decision making, emotion, impulse control and empathy
What is the orbitofrontal cortex responsible for?
The orbitofrontal cortex is responsible for cognitive processing of decision making
Drug used to treat premature ejaculation
SSRI
How do SSRIs work?
Prevent the reupake of 5-HT
-increase synaptic 5-HT within hours
How long does it take to feel the effects of anti-depressant medications?
2-3 weeks
What are 5-HT1A receptors
These are auto-receptors found throughout the CNS
- they are inhibitory and more receptors means greater inhibition
- they may provide a plausible mechanism to explain the delayed effects of most anti-depressants
Name 2 SSRIs which inhibit CYP450
Fluoxetine
Paroxetine
( anti=psychotics which do this: phenytoin, carbamazepine)
One of the first antidepressant drugs was which category of drug?
TCA
-imipramine
Name an anti-psychotic which may act as an anti-depressant at a low dose
Flupentixol
Dopamine receptors involved in anti-depressants
D2 receptors
Main inhibitory neurotransmitter in the brain
GABA
- in the developing brain, its actions are primary excitatory
What does GABA binding cause?
GABA binding causes opening of ion channels - either Cl- ions into the cell or K+ ions out of the cell
-this leads to a negative change in the transmembrane potential –> hyperpolarisation
What are ‘mood stabilisers’
Most mood stabilisers are anti-convulsant drugs
-the majority of mood stabilisers are more effective at reducing manic episodes than depressive episodes
List some anti-convulsant drugs
- carbamazepine
- valproate, sodium valproate
- lamotrigine
“atypical” or “second generation” drugs
- olanzapine
- risperidone
- aripiprazole
- quetiapine
How does lamotrigine work?
Blocking Na+ channels
-overall effect is to reduce excitability and cell firing (potentially useful if you have over-excitable neurons
One of the oldest mood stabilisers
Exact mechanism unknown:
-Inhibition of 5-‐HT autoreceptors
-Increase in anti-‐apoptotic factor Bcl-‐2
-Inhibition of glycogen synthase kinase-‐3 (GSK-‐3)
-Depletion of inositol
Upregulation of glutamate re-‐uptake
Lithium
IMPORTANT: Anti-psychotic mechanism of action
The true antipsychotic efficacy is related to their affinity of the D2 RECEPTOR
IMPORTANT: What is the desired effect of anti-psychotics
Desired effect is DA blockade in the MESOLIMBIC CIRCUITS
IMPORTANT: adverse effects of anti-psychotics?
Adverse effects (e.g. movement disorders, hyperprolactinaemia) are due to DA BLOCKADE in the NIGROSTRIATAL and TUBERO-INFUNDIBULAR PATHWAYS
