15 - Depression Flashcards
What is the requirements for a depression diagnosis?
5/9 of the symptoms in a 2 week period
What is the limbic system?
- Cortical border circling the brainstem
- Includes the amygdala, hippocampus, basal ganglia and cingulate gyrus with connects to the frontal cortex and hypothalamus
- Involved in emotions (subjective feelings - anger, fear, sadness, jealousy, embarrassment, joy)
Which system is associated with motivation?
Mesocorticolimbic dopamine system
Major depressive disorder is associated with increased activity in the ________ and decreased activity in the _______ of the brain compared to healthy controls
Major depressive disorder is associated with increased activity in the Limbic regions (amygdala) and decreased activity in the Striatum (regions involved with motivation) of the brain compared to healthy controls
Changes in brain activity reflect changes in _________ release and/or _______ response
Changes in brain activity reflect changes in neurotransmitter release and/or postsynaptic response

Neurotransmitters concentrated within the _________ region of the brain may be involved in mediating depression
Neurotransmitters concentrated within the limbic region of the brain may be involved in mediating depression
What is the Amine hypothesis of Depression?
The amine hypothesis of depression suggests that depression is due to the reduced functional activity of one or more brain amines (dopamine, norepinephrine, and serotonin).
What are the monoaminergic neurotransmitters?
- Dopamine
- Serotonin
- norepinephrine

What is the biosynthesis pathway for serotonin?
Tryptophan - converted to 5-HTP by tryptophan hydroxylase -> converted to serotinin by L-amino acid decarboxylase (AADC)
What is the catabolic pathway of serotonin?
Serotonin is broken down into 5-hydroxyindole acetic acid (5-HIAA) by MAO (Monoamine oxidase)
What is the biosynthesis pathway of Dopamine?
- Tyrosine is converted to L-DOPA by tyrosine hydroxylase (TH)
- L-DOPA is converted to Dopamine by L-amino acid decarboxylase (AADC)
What enzymes breakdown dopamine and what is the product?
MAO and COMT break dopamine into homovanillic acid (HVA)
What is the synthesis pathway of Noradrenaline (Norepinephrine)?
- Tyrosine is converted to L-DOPA by tyrosine hydroxylase (TH)
- L-DOPA is converted to dopamine by L-amino acid decarboxylase (AADC)
- Dopamine is converted to noradrenaline via dopamine Beta-hydroxylase (DBH)
What enzymes breakdown noradrenaline (norepinephrine) and what is the product?
PNMT and MAO
Product is adrenaline (epinephrine)
The monoaminergic neurotransmitters have a _________ role in the brain and are involved in ____, ______ and ______
The monoaminergic neurotransmitters have a modulatory role in the brain and are involved in mood, arousal, and attention
- alterations in these NT’s are associated with mood disorders (among other things)
- These NT’s include dopamine, norepinephrine and serotonin
What molecule is shown in the image?

Serotonin
What molecule is shown in the image?

Dopamine
What molecule is shown in the image?

Norepinephrine
What molecule is shown in the image?

Epinephrine
Fill in the blanks of the venn diagram
- Three functions of Norepinephrine
- Three fxns of Dopamine
- Four fxns of Serotonin
- Low Norepinephrine and Low Dopamine =________
- Low Norepinephrine and Low Serotonin = _______
- Low Serotonin and Low Dopamine = ________

Fill in the blanks of the venn diagram
- Three functions of Norepinephrine:
- Stress
- Energy
- arousal
- Three functions of Dopamine
- Motivation
- Salience
- Reward
- Four functions of Serotonin
- appetite
- anxiety
- well-being
- sleep
- Low Norepinephrine and Low Dopamine = Focus
- Low Norepinephrine and Low Serotonin = Depression
- Most antidepressants therefore target these two NT’s
- Low Serotonin and Low Dopamine = Learning

Depression results from inadequate _____________ (esp. _______ and _______) in the brain
Depression results from inadequate monoamine neurotransmission (esp. serotonin and norepinephrine) in the brain
What are three factors that could cause inadequate monoamine neurotransmission?
- less NT release
- fewer receptors
- impaired signal transduction
How was it decided that depression might be because of inadequate monoamine neurotransmission?
Through the use of the antihypertensive drug reserpine
- 15% of patients using this drug developed a syndrome indistinguishable from naturally occurring depression
- Discovered that reserpine depletes neurons of dopamine and norepinephrine transmitters

Why is it that ipronazid alleviated depression?
Ipronazid inhibited Monoamine oxidase (MAO) which is the enzyme responsible for the breakdown of monoamines = increased synaptic [monoamine NT’s]




