Depression Flashcards
What are the two types of depression
Unipolar - low mood -
reactive depression - something triggers it - stressful event
Bipolar - alternation between low and over exuberant moods
What regions of the brain are implicated in depression
Cingulate nucleus
Nucleus accumbens - limbic system control of emotion
Hippocampus
Amygdala - involved in the processing of fearful emotions
Peripheral hormonal aspect - increased levels of cortisol (stress hormone)
BDNF - brain derived neurotrophic factor
What are symptoms of depression
Low mood, apathy, loss or gain of weight, low self esteem, loss of appetite/libido
What is postnatal depression
Occurs in women shortly after birth - children of depressed mothers are more likely to become depressed themselves in later life
What is the monoamine theory of depression
proposed in 1965 - suggests depression results from functionally deficient monoaminergic transmission is the CNS
Based on the ability of MAO inhibitors to increase this transmission and drugs such as reserpine to deplete stores of monoamine neurotransmitters and therefore cause depression
What is the action of MAO inhibitors
MAO-A found in the CNS
Rapid and sustained increase in 5-HT (and noradrenaline/adrenaline) act by inhibiting uptake of noradrenaline/5-HT by monoaminergic nerve terminals
What are some side effects of MAOIs
Exaggerated effects in the peripheral nervous system
Tyramine acts as a catecholamine/monoamine releasing agent - also displaces stored monoamines from presynaptic vesicles - MAO-A breaks down dietary tyramine - if in conjunction with MAOIs - foods high in tyramine are ingested - a hypertensive crisis occurs (vasoconstriction)
What is the action of tricyclic antidepressants
Inhibit reuptake of 5-HT and noradrenaline
Tend to affect mAchRs - side effects related to mAchR antagonism
-dry mouth
-Blurred vision
-Constipation
What is the action of SSRIs (Specific serotonin reuptake inhibitors)
Inhibit 5-HT reuptake - less side effects and toxicity than TCAs, some patients - SSRI’s aren’t effective - need to control noradrenaline levels as well
What is the action of SNRIs
Specifically inhibit noradrenaline reuptake
What is the process of noradrenaline synthesis
Tyrosine - DOPA - dopamine - noradrenaline - adrenaline
What is the action of noradrenaline
Binds to alpha and beta adrenoceptors - Alpha2 adrenoceptors in the CNS - this is a negative feedback system so prevents further release of noradrenaline - Noradrenaline action terminated by COMT (catechol-o-methyl transferase)
Where are the majority of 5-HT neurons cell bodies found
In the raphe nucleus
What are serotonin functions
Hallucinations, mood, feeding behaviour, body temp, vomiting
What role does serotonin have on the limbic system
Regulates limbic processing - Decreased serotonin leads to anhedonia - inability to gain pleasure from pleasurable activities
