Lecture 19 - Basic Introduction to Psychopharmacology

Question 1

At rest what is the charge of the inside of a neuron?

Answer 1

Negative.

Question 2

Can a neuron “half fire”?

Answer 2

No.

Question 3

What type of neurotransmitter receptor does not act as an ion channel, but rather when it is bound by it’s ligand it recruits a 2nd messenger that causes the opening of an ion channel or other intracellular processes, e.g DNA modulation.

Answer 3

G-Protein Coupled Receptors.

Question 4

What is the difference between neurotransmission and neuromodulation?

Answer 4

Neurotransmission is short lasting, released at a synapse and effects only the postsynaptic neuron at that site.
Neuromodulation has a global cortical effect and is longer lasting. Neuromodulators are also only produced by specific neurons in specific modules in the brain.

Question 5

What aspect of a chemical/molecule/substance determines whether it is a neurotransmitter or a neuromodulator?

Answer 5

It’s functionality, i.e whether it acts on a more global level or only influences one other neurone (neuromodulator and neurotransmitter respectively).

Question 6

List some differences between neurotransmitters and neuromodulators and examples of these substances.

Hint: GABA, glutamate, dopamine, serotonin

Question 7

Neuromodulators influence the responsiveness of neurones.
True or false?

Answer 7

True.

Question 8

Are norepinephrine and noradrenaline the same or different neuromodulators?

Answer 8

They are the same - US and Aus say noradrenaline and norepinephrine respectively.

Question 9

Where are neuromodulators produced in the brain?

Question 10

Can serotonin neurones produce dopamine?

Answer 10

No. Serotonin neurones can only produce serotonin and that is the same for all neuromodulator producing neurones.

Question 11

What is psychopharmacology?

Answer 11

The study of psychoactive drugs and their effects on mental, emotional, behavioural states.

Question 12

What are the two ways in which psycho active drugs mimic or are able to bind to neurotransmitter/modulator receptors?

Hint: agonist and antagonist

Question 13

How can the function of neurotransmitters be altered by psychoactive drugs and/or genetic abnormalities?

Hint: synthesis, receptors,

Answer 13

Psychoactive drugs work by either mimicking the action of neuromodulators/transmitters or my preventing their action, synthesis, re-uptake, release etc.

Question 14

Are hormones neurotransmitters?

Answer 14

No. Explain why.
Hormones are produced in glands and are transported through the blood. They affect muscles and other areas of the body including neurons, but are not generally considered neurotransmitters or modulators.

Question 15

What are the two key receptors located on the post-synaptic membrane?

Answer 15

Ion gated.
G-coupled receptors.

Question 16

How do ion channels work?

Answer 16

When the correct neurotransmitter binds to the ion channel it opens essentially like a gate and allows the flow of a specific ion (e.g Na or K or Ca) to flow in or out of a cell.

Question 17

What is a G-protein coupled receptor?

Answer 17

G-protein coupled receptors work in this way: a neurotransmitter binds to the extracellular portion of the receptor. The receptor is coupled with a g-protein complex, and when neurotransmitter or other ligand binds to the receptor the shape of the receptor changes which in turn changes the g-protein complex which then detaches from the receptor and binds to a secondary messegner, which in turn can lead to a variety of downstream effects, such as opening an ion channel or leading to DNA changes.

Question 18

What is the difference between neurotransmitters and neuromodulators?

Answer 18

Neurotransmitters are chemicals released at a synapse that affects the adjoining neuron. They have a short term effect and they only influence one neurons, e.g Glutamate, GABA.

Neuromodulators on the other hand are produced by neurons in a specific area and then affect many neurons across the cortex. The effect of neuromodulators is longer lasting compared to neurotransmitters, e.g serotonin and dopamine.

These differences are functional differences.

Question 19

What is another difference between neurotransmitters and neuromodulators?

Answer 19

Another difference between the function of neurotransmitters and neuromodulators is that neurotransmitters either excite or inhibit a single neuron and influence whether it will fire an action potential.
Neuromodulators influence many neurons and make them either more easily fire action potentials or make it more difficult for them to fire action potentials. That is, they cause golbal cortical excitation or inhibition.

Question 20

Release and action of neurotransmitters is very fast. What aspect of neuron activity and function is relatively slow?

Question 21

How do psychoactive drugs work?

Answer 21

They work by micking the action of neurotransmitters or neuromodulators or they block receptors for these ligands.
They can behave as AGONISTS or ANTAGONISTS.
AGONISTS mimic the natural ligand and cause the same effect.
ANTAGONIST drugs work by blocking the natural ligand from binding to their receptors.

Question 22

Tryptophan is the base amino acid for which two neuromodulators?

Answer 22

Serotonin and Melatonin