MECHANISM OF PSYCHOTROPIC DRUG ACTION

Question 1

what are 4 strategies to help alleviate mental illness?

Answer 1

lifestyle
social support
psychotherapy
antidepressants

Question 2

what are the 4 dopamine pathways?

Answer 2

mesolimbic
mesocortical
nigrostriatal
tuberoinfundibular

Question 3

what is the function of the nigrostriatal pathway?

Answer 3

initiation and control of movement

Question 4

what is the function of the mesolimbic pathway?

Answer 4

reward and reinforcement

Question 5

what is the function of the mesocortical pathway?

Answer 5

cognition, planning and motivation

Question 6

what is the function of the tubero-infundibular pathway?

Answer 6

Inhibits the release of prolactin hormone from the pituitary gland

Question 7

what behaviour does noradrenaline influence?

Answer 7

sleep
wakefulness
attention
feeding behaviour

Question 8

where is noradrenaline most commonly released from?

Answer 8

neurones originating from the locus coeruleus in the brainstem

Question 9

where is serotonin released from?

Answer 9

neurones originating from the Raphe nuclei in the brainstem

Question 10

what does serotonin influence?

Answer 10

mood, emotional behaviour, sleep and the feeling of being satisfied

Question 11

where is GABA released from?

Answer 11

inhibitory neurones throughout the CNS

Question 12

what is GABAs mechanism of action?

Answer 12

It binds to a GABA-A receptor, which allows an influx of Cl- across the post-synaptic membrane which hyper polarises the neurone

Question 13

what are positive schizophrenic symptoms?

Answer 13

hallucinations
delusions
thought disorder

Question 14

what is the aim of treatment for positive symptoms?

Answer 14

To decrease dopamine transmission as they’re associated with the mesolimbic pathway.

Question 15

what are negative schizophrenic symptoms?

Answer 15

lack of motivation, reduced speech, reduced emotion, social withdrawal

Question 16

what is the aim of treatment for the negative schizophrenic symptoms?

Answer 16

To increase dopamine transmission as they are associated with the mesocortical pathway.

Question 17

what is the cause of schizophrenia?

Answer 17

unknown

Question 18

what is the dopamine hypothesis of schizophrenia?

Answer 18

hyperactivity of dopamine D2 receptor neurotransmission in subcortical and limbic brain regions contributes to positive symptoms of schizophrenia, whereas negative and cognitive symptoms of the disorder can be attributed to hypofunctionality of dopamine D1

Question 19

what are some arguments for the dopamine hypothesis?

Answer 19

Antipsychotics block dopamine receptors

Drugs that increase dopamine cause psychosis

PET and SPECT scans show increased brain Dopamine activity when people have Schizophrenia

Question 20

what are some arguments against the dopamine hypothesis?

Answer 20

Neurotransmitter effects are immediate, but antipsychotics take 2+ weeks to work on symptoms

Other transmitters appear to be involved with psychosis –Glutamate, 5HT2, 5HT1A

Critical potential role for environmental factors during brain development

Neurodegeneration associated with worsening symptoms. Linked to glutamate induced excitotoxicity

Question 21

what are antipsychotics mechanism of action?

Answer 21

antagonizes D2 receptors in the mesolimbic system

Question 22

what can antipsychotics be used to treat?

Answer 22

delusions, hallucinations, thought disorder, mania, delirium

Question 23

what’s the different between first and second generation antipsychotics?

Answer 23

1st- target D1 and D2

2nd- target D2 mostly and a little D1

Question 24

what is the effect of antipsychotics acting on the nigrostriatal pathway?

Answer 24

extrapyramidal side effects e.g. Parkinsonism, acute dystonia, dyskinesia

Question 25

what is the effect of antipsychotics acting on the tubuloinfundibular pathway?

Answer 25

excess prolactin | leads to galactorrhea, amenorrhoea, infertility

Question 26

what are some long term side effects of antipsychotics?

Answer 26

weight gain, diabetes, raised cholesterol

Question 27

what are some factors of depression?

Answer 27

``` persistent low mood/self esteem reduced enjoymnt fatigue sleep/appetite/weight/concentration changes loss of consciousness indecisiveness guilt hopelessness suicidal thoughts ```

Question 28

what is the monoamine theory of depression?

Answer 28

Depression is a result of a deficiency in brain monoamine neurotransmitters

Question 29

what are the 4 monoamine transmitters?

Answer 29

serotonin noradrenaline adrenaline dopamine

Question 30

what are arguments for MOA hypothesis?

Answer 30

Antidepressants increase the availability of monoamines at synapses People with depression can have lower levels of monoamine precursors/metabolites in their CSF or blood

Question 31

what are arguments against MOA hypothesis?

Answer 31

Neurotransmitter effects of antidepressants are immediate, but they take 2+ weeks to work on symptoms Cocaine and amphetamine mimic NA and 5-HT but do not act as antidepressants Iprindole is an antidepressant which does not affect NA or 5-HT reuptake (5-HT2 antagonist)

Question 32

what are some antidepressant types?

Answer 32

tricyclic antidepressants selective serotonin reuptake inhibitors monoamine oxidase inhibitors serotonin noradrenaline reuptake inhibitors

Question 33

what are tricyclic antidepressants mechanism of action?

Answer 33

block reuptake of noradrenaline and serotonin which allows it to have an elongated effect. However, they do not have an effect on Ach reuptake.

Question 34

what are the side effects of tricyclic antidepressants?

Answer 34

sedation, dry mouth, blurred vision, constipation, urinary retention, postural retention, can cause drug interactions, potentiates effects of alcohol and anaesthetics.

Question 35

what is the mechanism of selective serotonin re-uptake inhibitors?

Answer 35

Block re-uptake of serotonin from synaptic cleft to give it longer to work.

Question 36

what are the side effects of selective serotonin re-uptake inhibitors?

Answer 36

nausea and vomiting, sexual dysfunction, withdrawal reaction, can inhibit metabolism of other drugs.

Question 37

what is the mechanism of monoamine oxidase inhibitors?

Answer 37

Inhibit monoamine oxidase so serotonin and noradrenaline can’t be broken down. This allows the continuation of the neurotransmitter activity in the synaptic cleft.

Question 38

what are side effects of monoamine oxidase inhibitors?

Answer 38

postural hypotension, insomnia, weight gain, potential drug interactions.

Question 39

what is the theory about why antidepressants take 2 weeks to work?

Answer 39

Initially the increased 5HT in synapses is cancelled out by auto-receptors reducing 5HT release and more reuptake of the extra 5HT in the synapses. But after a couple of weeks, the auto-receptors desensitise, and the blocked reuptake transporters get internalised. So eventually there really is increased 5HT in the synapses

Question 40

what are symptoms of anxiety disorders?

Answer 40

``` nervousness foreboding agitation palpitations sweating bowel upset ```

Question 41

what are some benzodiazepines?

Answer 41

diazepam lorazepam temazepam

Question 42

what are benzodiazepines used for?

Answer 42

anxiety seizures increased muscle tone

Question 43

what are side effects of benzodiazepines?

Answer 43

drowsiness, confusion, forgetfulness, impaired motor control, tolerance, dependence, respiratory depression