W3L1: Serotonin, Mood Disorders, Designer Drugs

serotonin (5-hydroxytryptamine = 5-HT)

mood regulator, sleep, arousal, appetite, temperature, working memory, hallucinations

serotonin: neuromodulator

influence activity of a variety of neurone throughout brain

serotonin: location

raphe nucleus, cortex, amygdala, hippocampus

serotonin: receptor subtyes

has different effects depending on receptor subtypes, drugs often only activate one or a few subtypes so will be more selective then natural neuromodulator

serotonin: synthesis

caused by tryptophan synthesised into serotonin

serotonin: tryptophan

amino acid found in food - chicken, cheese, chocolate

monoamine oxidase

modulate and get rid of neuromodulators (serotonin, dopamine, noradrenaline) to shut down neurotransmitter system

serotonin is…

all about modulating (mood, sleep, appetite etc.)

serotonin: depression

some serotonergic abnormality occurring

depression: familial clustering: neighbour

16%

depression: familial clustering: sibling

30%

depression: familial clustering: identical twin

>80%

serotonin: depression: serotonergic receptors

less in depressed people (has relation to depressive symptoms)

serotonin: antidepressants (SSRI’s)

citalopram, fluoxetine, paroxetine, sertraline (similar structure to serotonin so they can attach to serotonergic receptors)

SSRI - Selective Serotonin Reuptake Inhibitors

prevents reuptake of serotonin back into presynaptic neuron

SSRIs: long latency onset theories: altered gene expression

slow changes in action of different processes within neuron (neurotransmitter synthesis and storage), changes in structure of neuron (synaptic remodelling)

SSRIs: long latency onset theories: stress response

shuts off response underlying depressive symptoms, allowing for important neural adaptations

SSRIs: long latency onset theories: increased levels of neurogenesis

birth of new brain cells change/strengthen important mood related circuits in brain

SSRIs: in clinical populations

reduces symptoms of depression

SSRIs: in healthy people

increases empathy and prosocial behaviour

serotonin: monoamine oxidase inhibitors (MAOIs)

blocks enzyme from breaking down serotonin (causes upregulation of serotonin because there’s nothing to break it down) - can lead to lethal levels of serotonin if taken too much

MDMA

key MAOI

more dopaminergic than serotonergic the drug

more addictive