What is GHB and how does it work?

Question 1

What is GHB?

Answer 1

A drug that is used as a date rape

Question 2

What kind of receptor is GABAb?

Answer 2

A GPCR

Question 3

How does the GABAb system work?

Answer 3

As a dimer (i.e. you need two of them activated to create an effect)

Question 4

What are the two halves of the dimer that are required to carry out a signal?

Answer 4

1. GABAb1

2. GABAb2

Question 5

What is the function of the GABAb1 receptor?

Answer 5

The activator

Question 6

What is the function of the GABAb2 receptor?

Answer 6

the signaller

Question 7

Describe the cascade of GABAb?

Answer 7

GABAb acts on NMDA receptors

1. Alpha subunit cleaves; the beta-gamma subunit goes on to negatively influence voltage-gated Ca2+ channels
2. alpha subunit acts on Gi pathway (inhibits adenylyl cylcase from making cAMP from ATP)
3. NMDA receptor has to be phosphorylated by protein kinase a to be activated

Question 8

How does the GABAb receptor inhibit the NMDA receptor?

Answer 8

By preventing phosphorylation (therefore it inhibits the excitatory response)

Question 9

What do presynaptic GABAb receptors prevent?

Answer 9

Ca2+ from causing vesicle to dock and release NTs

Question 10

What does GHB stand for?

Answer 10

gamma hydroxybuterate

Question 11

What is GHB synthesized from?

Answer 11

GABA

Question 12

Describe the synthesis of GHB?

Answer 12

succinic semialdehide makes GHB from GABA

Question 13

What does a low dose of GHB produce?

Answer 13

Excitement and euphoria (with some memory problems)

Question 14

What is liquid X?

Answer 14

GHB at low doses (is paired with other club drugs)

Question 15

What do moderate doses of GHB produce?

Answer 15

More memory problems and sedation

Question 16

What do high doses of GHB produce?

Answer 16

coma and/or death

Question 17

Why is GHB effective as a memory impairer in date rape situations (exam question)?

Answer 17

Because the LTP in NMDA receptors is blocked by the GABAb receptor cascade

Question 18

What is an orphan receptor?

Answer 18

Proteins that act like receptors, but with no known ligand that specifically binds to it

Question 19

What property can GHB have when it comes to neurotransmission (other than the possibility of it being its own neurotransmitter)?

Answer 19

GHB could be a GABAb co-signaller

Question 20

What are monoamine neurotransmitters?

Answer 20

They are a class of compounds that have a single amine

Question 21

What are the two classifications of monoamines?

Answer 21

Catecholamines and 5HTs

Question 22

What are the catecholamine NTs?

Answer 22

1. Dopamine (DA)
2. Norepinephrine (NE)
3. Epinephrine (Epi)

Question 23

Is serotonin a catecholamine?

Answer 23

No, but it is a monoamine

Question 24

What is the technical difference between epinephrine and adrenaline?

Answer 24

Epinephrine is used when referring to the effects in the CNS (i.e. in the brain) and adrenaline is used when referring to the effects in the PNS (i.e. in heart rate, pupil dilation, etc)

Question 25

What is a rate limiting step?

Answer 25

The slowest step in the synthesis of a monoamine - this step determines how much is released, and how quickly more is synthesized

Question 26

Describe the synthesis of dopamine.

Answer 26

1. tyrosine gets into the brain via a BBB transporter 2. tyrosine gets transformed into L-Dopa via tyrosine hydroxylase (TH) 3. L-dopa gets transformed into dopamine via dopa decarboxylase

Question 27

Describe the synthesis of norepinephrine.

Answer 27

1. tyrosine gets into the brain via a BBB transporter 2. tyrosine gets transformed into L-Dopa via tyrosine hydroxylase (TH) 3. L-dopa gets transformed into dopamine via dopa decarboxylase 4. dopamine gets transformed into norepinephrine via dopamine-beta-hydroxylase

Question 28

Describe the synthesis of epinephrine

Answer 28

1. tyrosine gets into the brain via a BBB transporter 2. tyrosine gets transformed into L-Dopa via tyrosine hydroxylase (TH) 3. L-dopa gets transformed into dopamine via dopa decarboxylase 4. dopamine gets transformed into norepinephrine via dopamine-beta-hydroxylase 5. norepinephrine gets transformed into epinephrine via phenylethanolamine-N-methyltransferase

Question 29

What does impulse dependent mean?

Answer 29

That the substance is only effective when active firing of the neuron is occurring (for example, cocaine is impulse dependent, because it needs DA in order to enhance its signal)

Question 30

What does impulse independent mean?

Answer 30

The neuron doesn't have to fire for the substance to have an effect - an example of an impulse independent substance would be meth

Question 31

What effect do psychostimulants have?

Answer 31

They are indirect agonists that affect DA release

Question 32

How is dopamine's signal terminated?

Answer 32

1. through reuptake (this is the primary method of signal termination) via DAT 2. it is metabolized

Question 33

Give some examples of medications that act on dopamine transporters.

Answer 33

1. ADHD medication (ex. dexadrine, adderall, concerta) 2. cocaine 3. methamphetamine

Question 34

How does ADHD medication affect neurotransmission?

Answer 34

These medications reverse the dopamine transporter DAT to instead push out more dopamine

Question 35

How does cocaine affect neurotransmission?

Answer 35

It blocks the DA transporter (therefore it acts as an antagonist)