L8 - 5-HT - 3 IRL flashcards + 1 flowchart

Question 1

Where does 5-HT come from?

Answer 1

Dorsal raphe nucleus and the gut - stored in platelets (5%)

Question 2

Whats unique about 5-HT3?

Answer 2

Ligand gated channel

Question 3

Whats unique about 5-HT1E?

Answer 3

Not found in rats - hence can’t do exp to figure out function

Question 4

5-HT1 family is coupled to which G-protein?

Answer 4

Gi/0

Question 5

5-HT2a,b,c is coupled to which G-protein?

Answer 5

Gq/11

Question 6

5-ht4 is coupled to which G-protein?

Answer 6

Gs

Question 7

5-ht5a is coupled to which G-protein? What about b?

Answer 7

Gi/0, B- none identified (has STOP codon)

Question 8

5-ht6, 7 is coupled to which G-protein?

Answer 8

Gs

Question 9

Why do SSRIs take time to work?

Answer 9

Too much 5-HT binds to 5-HT1 a,b,d autoreceptors - inhibiting release of 5-HT. Eventually autoreceptors are downregulated or desensitized - leading to increased 5-HT output. The need for downreg or desen. is why there is a delay in SSRIs effects.

Question 10

Which 5-HT receptor is a target for LSD?

Answer 10

5-HT2A

Question 11

Where are 5-HT2B receptors found?

Answer 11

Interstitial tissue of heart valves - none are found in the brain

Question 12

Where are 5-HT2C receptors found?

Answer 12

Hypothalamus

Question 13

Where are 5-HT2A receptors found?

Answer 13

Layer V of cerebral cortex

Question 14

List 5-HT2A agonists (3) and antagonists (2)

Answer 14

Ag (Hallucinogenics): LSD, DOI, psilocybin

Antag (Antipsychotics): Clozapine (best antipsychotic as it has affinity to lots of receptors and transporters), atypical antipsychotics

Question 15

List 5-HT2B agonists (3) and antag (1)

Answer 15

Ag: Fenfluramine (disrupting 5-HT vesicular storage of the neurotransmitter, and reversing serotonin transporter function) , Benflurorex, MDMA (ecstasy)
*Appetite suppressants BUT cause valvulopathies

Antag: Methysergide
*Migraine

Question 16

!List 5-HT2C agonist and antagonist

Answer 16

Ag: Lorcaserin (anti-obesity. aids in treating addiction)

Antag: Agomelatine (TREATS depression, Generalized anxiety disorders (GAD))
*As it is a melatonin receptor agonist - you have to take it before going to bed rather than in the morning

Question 17

Inverse Agonist

Answer 17

An agent that binds to the same receptor as an agonist but induces a pharmacological response opposite to that agonist. A neutral antagonist has no activity in the absence of an agonist or inverse agonist but can block the activity of either.

Question 18

?Ergotamine

Answer 18

5-HT2B antagonist?

• Furthermore, it is an antagonist at the 5-HT2C receptor, while at the 5-HT1A receptor it serves as a partial agonist
• Also binds to 5-HT2A receptor

Question 19

Atypical antipsychotics act at what R

Answer 19

D2, 5HT2A and many more

Question 20

All triptans act as

Answer 20

5HT1B/1D agonists

*Triptans are a group (class) of drugs that are used to ease the symptoms of a migraine attack or cluster headache.

Question 21

Antiemetics act as

Answer 21

5HT3 antagonists

Question 22

What 5HT R agonism is banned because of its detrimental effects?

Answer 22

5HT2B

Question 23

5HT2C agonist treats

Answer 23

Obesity

Question 24

What 5HT R are not targets for any meds

Answer 24

5HT5 or 5HT1e

Question 25

Pindolol

Answer 25

Partial 5HT1A/1B/1D autoR antagonist that is used to block autoR so that 5HT release is not inhibited

Question 26

2 AutoR involved when using SERT

Answer 26

Somatodendritic 5HT1A

Presynaptic 5HT1B/1D

Question 27

5HT2A agonist induces

Answer 27

Hallucinations