Lec #1 The Human Brain

Question 1

Dopaminergic neuron

Answer 1

neuron that releases dopamine

Question 2

Glutamatergic neuron

Answer 2

neuron that releases glutamate

Question 3

Excitatory neurotransmitter

Answer 3

released neurotransmitter when bonded to a downstream neuron, causes the neuron to fire more and depolarize the membrane

Question 4

Inhibitory neurotransmitter

Answer 4

released neurotransmitter when bonded to a downstream neuron, causes the neuron to fire less and hyperpolarize the membrane

Question 5

membrane potential

Answer 5

• the difference in electrical charge or voltage between the inside and outside of a neuron
• typically negative inside the cell relative to the outside. This difference in charge results from the selective permeability of the cell membrane to ions (charged particles): sodium, calcium and potassium and chloride (positive)

Question 6

what happens when if a membrane is depolarized enough?

Answer 6

a strong electrical current goes down the axon, the action potential with sufficient amount of positive ions flowing in and triggers calcium channels to enter the axon terminal and causes the release of neurotransmitters

Question 7

action potential

Answer 7

the electrical current that flows through the axon. When it reaches the end of the axon (terminal), the electrical cuttrny triggers the release of neurotransmitter

Question 8

drug

Answer 8

A chemical that interacts with a protein to alter its activity.

Question 9

endogenous ligand (endogenous agonist)

Answer 9

naturally occurring substance within the body that can bind to and activate specific receptors in the body, such as cell surface receptors or intracellular receptor

Question 10

receptor

Answer 10

The protein that is altered by the drug through a physical interaction between the drug and the protein.

Question 11

therapeutic target

Answer 11

The target (receptor) that is believed to be the reason why the drug is
effective to treat a disease condition.

Question 12

therapeutic effect

Answer 12

The beneficial change in physiology that occurs with drug administration.
For example, analgesia (pain-relief) is the therapeutic effect of morphine.

Question 13

off-set target

Answer 13

The interaction of the drug with other proteins that are not part of the therapeutic effect. Off-target actions of the drug can contribute to unwanted adverse effects(also called side effects). If a drug has off-target effects that are the reason for the adverse effects, it suggests that a more selective drug could provide the same benefits with fewer side effects.

Question 14

adverse effect

Answer 14

An undesirable and/or pathogenic change in physiology that occurs with drug administration.

Question 15

mechanism of action

Answer 15

A drug’s mechanism of action is our current understanding of that drug’s target(s), and how the interaction of drug and receptor leads to a change in neuron activity that ultimately changes brain function.

Question 16

affinity

Answer 16

the strength of the attraction between the drug and the receptor. A drug with high affinity will have several points of electrostatic interactions. For example,
several negatively charged ions on the drug will come in contact with positively charged amino acids on the receptor. A drug with high affinity is often very selective for its target, because each protein has a unique shape.

Question 17

selectivity

Answer 17

the number of proteins that are affected by a drug. A highly
selective drug will only bind one or two proteins, while a non-selective drug will bind several.

Question 18

what are 3 steps of finding drugs to treat brain diseases?

Answer 18

1. take a natural product and isolate the psychoactive chemical
2. identify the receptor for that chemical
3. change the chemical structure to improve the drug and how well it fits/ acts on the receptor

Question 19

Acronym for ADME

Answer 19

Absorption
Distribution
Metabolism
Elimination

Question 20

agonist drug

Answer 20

a substance that binds to a receptor and activates it, often mimicking the effects of endogenous (naturally occurring) compounds or neurotransmitters.

Question 21

antagonist drug

Answer 21

substance that binds to a receptor without activating it and blocks or inhibits the receptor’s normal activity.
Antagonists compete with agonists (including endogenous ligands) for receptor binding sites, preventing the receptor from being activated.
Antagonist drugs are used to reduce or block the effects of agonists, typically for therapeutic purposes or to study the specific functions of receptors.

Question 22

what happens when a neurotransmitter binds itself to ion channels:

Answer 22

2 reactions:
- If the neurotransmitter binding to its receptor on the ion channel leads to the opening of ion channels that allow positively charged ions (typically sodium, Na+) to flow into the neuron, this results in an excitatory postsynaptic potential (EPSP).
- when a neurotransmitter binding to its receptor opens ion channels that allow negatively charged ions (typically chloride, Cl- or potassium, K+) to flow into the neuron or positively charged ions (such as potassium, K+) to flow out of the neuron, this results in an inhibitory postsynaptic potential (IPSP).

Question 23

what does it mean when the drug is transient (reversible)

Answer 23

the drug does not go on the receptor forever, can go into the bloodstream and be eliminated

Question 24

what happens when the receptor for a drug is activated so much by an agonist?

Answer 24

desensitization= receptor activated so much, that it refuses to send the signal anymore

Question 25

what is the only way to stop the action of a drug that binds irreversibly to a receptor?

Answer 25

make a new receptor (takes several hours)

Question 26

What happens when a drug is present continuously in a cell?

Answer 26

The cell will adapt to the presence of the drug.

Question 27

What occurs with receptors when a drug acts as an antagonist?

Answer 27

Receptors are sometimes upregulated, leading to the production of more receptor proteins.

Question 28

What happens to receptors when a drug functions as an agonist?

Answer 28

Receptors are sometimes downregulated, resulting in a decrease in the number of receptor proteins.

Question 29

what part of the neuron determines whether a neuron will fire

Answer 29

axon hillock