Antipsychotics + dopamine pathway video

Question 1

What neurotransmitter is primarily targeted by antipsychotics?

Answer 1

Dopamine

Question 2

Antipsychotics are generally dopamine antagonists. true/false?

Answer 2

True

Question 3

What are the 4 dopaminergic pathways affected by the drugs?

Answer 3

Mesolimbic
Mesocortical
Nigrostriatal
Tuberoinfundibular

Question 4

Mesolimbic pathway role?

Answer 4

Transmits dopamine from midbrain (VTA - ventral tegmental area) to ventral striatum.

Involves the nucleus accumbens which is responsible for motivations, emotions and rewards.

Thought to be responsible for reducing the positive symptoms of schizophrenia.

Question 5

Mesocortical pathway role?

Answer 5

Transmits dopamine from midbrain (VTA) to the prefrontal cortex.

Hypofunction (low function) of this pathway results in the negative effects of schizophrenia.

Question 6

Nigrostriatal pathway role?

Answer 6

Transmits 80% of the brains dopamine from the pars compacta of the substantia nigra to the putamen and caudate nucleus.

Antipsychotics that reduce dopamine can target this pathway resulting in hypofunction and resulting in EPSE (extra-pyramidal side-effects), similar to the pathophysiology of Parkinson’s disease.

Question 7

Tuberoinfundibular pathway role?

Answer 7

Transmits dopamine from hypothalamus to pituitary gland.

Dopamine in this pathway acts to inhibit prolactin. So hypofunction/blockage of the D2 receptors of this pathway would lead to hyperprolactinaemia causing symptoms such as erectile dysfunction, galactorrhoea and lack of libido

Question 8

What is the role of ventral tegmental area in addiction?

Answer 8

The VTA is part of the reward circuit in the brain; psychoactive drugs directly influence the release of dopamine in this area, so leading to addiction and its associated behaviours.

Psychoactive drugs include heroin, ecstasy , tobacco, alcohol and cocaine.

Question 9

What are positive and negative symptoms of schizophrenia?

Answer 9

Positive symptoms reflects an excess or distortion of normal function e.g. delusions, hallucinations and disorganised bahaviour.

Negative symptoms refer to a diminution or absence of normal behaviors related to motivation and interest (e.g preference to solitude or lack of pleasure) or expression (e.g. restriction of speech).

Question 10

Positive symptoms of schizophrenia are usually easier to treat than negative symptoms. true/false?

Answer 10

True