neurotransmitters in depression

Question 1

areas of brain that are particularly affected?

Answer 1

basel ganglia
neocortex: prefrontal cortex
limbic system

Question 2

deep brain stimulation of the subthalamus (limbic system) in depression (link with mood)

Answer 2

mood changes in positive direction, but lower mood also reported

Question 3

main functions of limbic system

Answer 3

emotion
motivation
memory

Question 4

neuro transmitters - where is information received?

Answer 4

dendrites –> axon –> terminal buttons

synapse at synaptic cleft

Question 5

what are the types of neurotransmitters?

Answer 5

inhibitory
excitatory

ion channel
second messenger

Question 6

what are the 2 main neurotransmitters for depressive disorders?

Answer 6

noradrenaline

serotonin

Question 7

other neurotransmitters important in psychiatric conditions?

Answer 7

dopamine
acetylcholine
GABA (alcohol)
glutamate

Question 8

NA function in the brain?

Answer 8

mood
suggests a role in behaviour (arousal and attention)
implicated in memory functions

Question 9

where is NA made? transported to?

Answer 9

made in locus coeruleus in the brainstem and transported to several areas of the cortex

Question 10

receptors for NA?

Answer 10

4 types: alpha 1 + 2, ß1, ß2

alpha receptors play role in arousal and mood

Question 11

NA synthesis?

Answer 11

tyrosine – (tyrosine hydroxylase)–> dopa – (AA decarboxylase)–> dopamine – (dopamine ß-hydroxylase)–> NA –> adrenaline

Question 12

evidence of NA being implicated in causation of depression?

Answer 12

AMPT inhibits tyrosine to L-DOPA:
increase sleep, anger, depressive symptoms
decrease calmness

Question 13

anti-depressants?

Answer 13

NARI (NA reuptake inhibitor):
TCA (tricyclic anti-depressants)
SNRI’s

Question 14

effects of other substances e.g. reserpine?

Answer 14

depletes the nerve ends of NA

Question 15

role of serotonin in the brain?

Answer 15

sleep
impulse control
appetite
mood

Question 16

where is serotonin produced? transported?

Answer 16

produced in brain stem (Raphe nuclei) and transported to cortical areas and limbic system

Question 17

serotonin synthesis?

Answer 17

tryptophan (AA) –> 5-HTP –> serotonin –> N-acetyl serotonin –> melatonin

Question 18

serotonin receptors?

Answer 18

complex, many different pre + post serotonergic receptors

Question 19

reasons for implicating serotonin (5HT) in depression?

Answer 19

5HIAA depletion in CSF in patients with depression (metabolite of serotonin)
tryptophan depletion (precursor for serotonin) causes depression
PET + SPET studies
reserpine

Question 20

anti-depressants?

Answer 20

SSRI (serotonin reuptake inhibitor)
TCA
SNRI’s
MAO-I

Question 21

dopamine and depression?

Answer 21

3 main pathways
role in parkinson’s disease (40% PD pts have depression)
release gives pleasure feeling (cocaine + amphetamines)
HVA low in patients with depression
role in ‘drive’
ECT has effect on dopamine system
effects of anti-parkinson’s medication
main neurotransmitted implicated in schizophrenia

Question 22

mono-amine hypothesis of depression focuses on the role of?

Answer 22

serotonin
NA
dopamine

Question 23

neurotransmitter changes in mania?

Answer 23

NA increased in manic phrase in BPM patients
serotonin findings inconsistent
antipsychotics block dopamine and have anti-manic (and depressive) properties
dopamine agonists can cause main symptoms

Question 24

mood stabilisers?

Answer 24

lithium: classical mood stabiliser
exact mechanism unknown
positive effect on BDNF transcription
possible positive effect on serotonin production

Question 25

What is GABA?

Answer 25

most important inhibitory neurotransmitter in the brain
GABA (A) and GABA (B) receptors
several chemicals affect the chloride permeability of the membrane
affinity for alcohol, benzodiazepines and steroids

Question 26

GABA (A) receptors?

Answer 26

ion channels:
if the receptor is activated, the membrane permeability for chloride increases and this has an inhibitory effect on the neuron

Question 27

GABA (B) receptors?

Answer 27

second messenger receptors (e.g. GPCR)