serotonin and mood disorders

Question 1

serotonin

Answer 1

• 5-HC
• important in many functions like sleep, arousal, appetite, working memory

Question 2

serotonin pathways

Answer 2

• originate from the Raphe nucleus
• all serotonin is synthesized and released from neurons originating in the Raphe nucleus. the 5H-YT is synthesized in the cell body and then transported to the synapses where it is stored. when the neuron fires, the stored 5HT is rapidly released from the synapse

Question 3

receptor subtypes of serotonin

Answer 3

• serotonin has different effects in different brain areas depending on the receptor subtypes. Drugs will often activate one or a few receptor subtypes, so will be more selective than the natural neuromodulator

Question 4

serotonin synthesis

Answer 4

• tryptophan- an amino acid found in food (cheese, chicken, chocolate)

Question 5

depression vs grief

Answer 5

• ## grief rarely produces the cognitive symptoms of depression such as low self esteem, self loathing or suicidal thoughts

Question 7

depression & serotonin

Answer 7

• in a post mortem study, patients with depression had reduced number of serotonin receptors.
• a gene involved in the transportation of serotonin is linked to increased risk of developing depression

Question 8

tryptophan depletion

Answer 8

• induced transient depressive symptoms in recovered unmedicated depressed patients (and in some people without depression)

Question 9

depression and serotonin vulnerability

Answer 9

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- impaired serotonin function may be a risk factor leading to people being vulnerable when developing depression
- depression is 5 x more likely after stressful events
- stress= increased release of a range of hormones, serotonin= important because it manages the feedback control of the brains stress response

Question 10

Serotonin antidepressants

Answer 10

• they prevent the reuptake of serotonin- to increase serotonin in the synaptic cleft.

Question 11

selective serotonin reuptake inhibitors (SSRI’s) therapeutic effects

Answer 11

• SSRI’s are very slow acting and often takes weeks for any therapeutic effects to be achieved
• if taken orally the drug reaches the brain after 1 hour. and should block serotonin reuptake immediately once in the brain
• therefore, improved mood cannot result directly from increased serotonin around the synapse

Question 12

theories of long latency of onset

Answer 12

• altered gene expression- leading to slow changes in the action of different processes within a neuron, or even change in the structure of the neuron
• shuts off a pathological elevated stress response for important neural adaptions
• increased levels of neurogenesis (birth of new brain cells) change or strengthen the mood related to circuits in the brain

Question 13

new brain cell growth

Answer 13

• new evidence suggests SSRI’s could promote new brain cell growth, treating past damage and may even be ‘neuroprotective’, protecting against future damage associated with depression.
• The serotonin theory of depression: a systematic umbrella review of evidence. They found there is some evidence that long term SSRI induces serotonin because it increases the levels artificially, meaning the ability of patients to produce serotonin once off the meds depleted.

Question 14

SSRI’s mood and personality

Answer 14

in clinical populations: reduces symptoms of depression
in health people: increases empathy and prosocial behavior

Question 15

Monoamine oxidase inhibitors: another type of antidepressant

Answer 15

• blocks the breakdown of serotonin, can lead to lethal levels of serotonin if the individual diet is not controlled.
• now used as last resort and strictly controls diet