SP.236: Pharmacology
Antidepressants
Zak Fallows
A note on layout: The neurotransmitters are listed from the most often targeted by antidepressant drugs (serotonin) to the least often
targeted (dopamine). The mechanisms are listed in functional or “life cycle” order from the perspective of the neurotransmitter, which
is first synthesized, then released, binds receptors, and ultimately is broken down. The drug classes are listed in order of historical
discovery.
Neurotransmitters
Mechanisms
(to boost NT)
Serotonin
Norepinephrine
Dopamine
SER, 5-HT
NE
DA
Increase synthesis
Cause release
Receptor agonist
Partial agonist
Presynaptic antagonist
Inhibit reuptake
Inhibit breakdown
Antipsychotics*
Antidepressant
classes
Monoamine
oxidase inhibitors
Tricyclic
antidepressants
Selective serotonin
reuptake inhibitors
Satiety
Fight or flight
Salience
Example:
Levodopa, 5-HTP
Amphetamine (Adderall®)
Pramipexole
Buspirone (BuSpar®)
Mirtazapine (Remeron®)
Fluoxetine (Prozac®)
Phenelzine (Nardil®)
1952
MAOIs
1953
TCAs
1955
SSRIs
High:
Fullness, contentment
Alert, concentration, memory
Reward, desire, learning, alert
1977
First:
Chlorpromazine
(Thorazine®)
Iproniazid and
isoniazid
Imipramine
(Tofranil®)
Zimelidine
Low:
Anxiety, OCD, aggression, hungry
Inattentive
Inactive, unmotivated, hungry
Boosts:
Used for:
DA and SER, respectively
PD and useless, respectively
NE > DA >> SER
DA
SER
SER, NE
SER
SER, NE, DA
ADHD, narcolepsy
Parkinson’s (PD)
Anxiety > depression
Depression > anxiety
Depression, anxiety, OCD
Depression > anxiety
Notable:
Mechanism:
Haloperidol (Haldol®)
Antagonist*
Phenelzine, selegiline,
moclobemide, harmaline
Amitriptyline (Elavil®),
chlomipramine (Anafranil®)
Inhibit
breakdown
Inhibit
reuptake
Fluoxetine (Prozac®), sertraline (Zoloft®),
paroxetine (Paxil®), citalopram (Celexa®),
escitalopram (Lexapro®), fluvoxamine
(Luvox®), dapoxetine
Inhibit
reuptake
MIT OpenCourseWare
http://ocw.mit.edu
ES.S10 Drugs and the Brain
Spring 2013
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