Pharmacology of the CNS

Question 1

What are the criteria for a neurotransmitter? (NT)

Answer 1

1. Presence
2. Stored in vesicles
3. Release
4. Effect
5. Termination of effect

Question 2

What are some properties of transmitters in the central nervous system (CNS) ?

Answer 2

• They are ALWAYS agonists
• They can produce fast or slow effects
• They can excite or inhibit
• They are determined by receptors

Ion channels — SLOW — neurotransmission
2nd messengers — FAST — neuromodulation

Question 3

What are the major EXCITATORY and INHIBITORY transmitters in the brain?

Answer 3

Excitatory: GLUTAMATE

Inhibitory: GABA

Question 4

Which neurotransmitters have mixed effects?

Answer 4

Acetylcholine (ACh)
Noradrenaline (NA)
Dopamine (DA)
Serotonin (5-HT)

Question 5

What kinds of molecules are substance P and opioids?

Answer 5

Peptides

Question 6

Is substance P excitatory or inhibitory?

Are opioids excitatory or inhibitory?

Answer 6

Substance P — excitatory

Opioids — Inhibitory

Question 7

Is Nitric Oxide (NO) excitatory or inhibitory?

Is Adenosine excitatory or inhibitory?

Answer 7

NO and adenosine are BOTH excitatory.

Question 8

Which receptors does Glutamate bind?
How do these receptors differ in their properties?

And what about for substance P?

Answer 8

AMPA — Fast
Kainate — Fast
NMDA — Delayed
Metabotropic (GPCR) — Slow

Substance P: Neurokinin 1 — Slow

Question 9

Which two neurotransmitters are present in small amounts in the nervous system?

Answer 9

Substance P and Opioids

Question 10

State some processes in which Glutamate plays a crucial role.

Answer 10

Pain — wind-up, LTP in spinal cord
Memory — LTP, etc. in hippocampus
Epilepsy — forebrain
Development — neuronal contacts

Cell death — excessive activation of Glutamate receptors such as NMDA results in excess influx of calcium, which increases osmotic pressure, thereby activating enzymes which increase [NO] subsequently releasing free radicals which leads to death.