Psychopharmacology

Question 1

What are the monoamine NT systems?

Answer 1

Noradrenaline, dopamine, serotonin

adrenaline + histamine are also monoamines

Question 2

What are the two main groups of symptoms in psychiatric disorders?

Answer 2

Affective (anxiety + depression)

Psychotic (bipolar / schizophrenia)

Question 3

Which NTs involved in depression, schizophrenia and ADHD?

Answer 3

depression: NA, 5HT
schizophrenia: DA, 5HT
ADHD: NA, DA

Question 4

Why are monoaminergic neurons different to glutamatergic neurons?

Answer 4

Monoamine neurons: cell bodies sit in groups of nuclei which project to different parts of brain.

Great diversity of post-synaptic receptors: results in diversity of function that transmitter known to modulate

e.g. NA neuron, 90% neurons found in locus coeruleus at back of brainstem, then sends projections to frontal regions

Question 5

What is monamine oxidase + COMT?

Answer 5

Monoamine oxidase + Catechol-O-methyltransferase (COMT) = intracellular enzymes, inactivate/degrade monoamines?

Question 6

Where are monoamine reuptake transporters located?

Answer 6

Both the dendritic/cell body region & terminal region

Also on glial cells

Question 7

How do autoreceptors produce negative feedback in monoaminergic neurons?

Answer 7

Inhibitory effect on calcium channels + positive effect on K+ channels → hyperpolarisation → reduced excitability of nerve (more depolarisation needed to elicit exocytosis)

Question 8

How do autoreceptors produce negative feedback in monoaminergic neurons?

Answer 8

Inhibitory effect on calcium channels + positive effect on K+ channels → hyperpolarisation → reduced excitability of nerve (more depolarisation needed to elicit exocytosis)

e.g. a2 adrenoreceptor: Gi coupling (reduces cAMP, inactivates calcium channels, activates potassium channels)

Question 9

How do serotonin and noradrenaline neurons interact?

Answer 9

NA= major regulator of the serotonin system: projections from locus coeruleus → dorsal raphe (synapse onto cell bodies in dorsal raphe)

Reciprocal: feedback from serotonergic system to LC via an interneuron

NA input to DR acts on a1 receptors (GPCR) stimulate firing (therefore calcium-dependent serotonin release)

Or if NA is released onto terminal region at synapse can inhibit 5-HT release through activation of alpha2-autoreceptors