Why do psychostimulants sometimes produce a calming effect?

Question 1

What is a readily releasable pool?

Answer 1

Vesicles that stay close to the synapse

- these release NTs under normal circumstances

Question 2

Do all of the catecholamines have the same synaptic transporter?

Answer 2

Yes

Question 3

What is the PRIMARY DA signal termination?

Answer 3

Through reuptake via the dopamine transporter

Question 4

What is the other way that DA’s signal can be terminated?

Answer 4

Through two enzymes metabolizing the NT:

1. COMT
2. MAO
   - both of these break down monoamines

Question 5

Which transporter does dopamine have the highest affinity to?

Answer 5

NET (norepinephrine’s transporter) vs. its own (DAT)

Question 6

Which receptors do epinephrine and norepinephrine act on?

Answer 6

Adrenergic receptors

Question 7

What are the two families of adrenergic receptors?

Answer 7

Alpha (1, 2) and beta (1, 2, 3)

Question 8

Which part of the PNS does epinephrine act on?

Answer 8

The sympathetic NS (to activate the fight/flight response)

Question 9

Where do the cell bodies of NE lie? Where do these neurons project to?

Answer 9

NE cell bodies lie in the locus ceruleus and project to the cortex, thalamus and hypothalamus

Question 10

What are the cortex, thalamus and hypothalamus important for? What have these areas been implicated in?

Answer 10

Orienting response (hypervigilance)
- have been implicated in depression and anxiety

Question 11

What is a reserve pool?

Answer 11

Vesicles waiting for sustained firing

Question 12

Why do beta blockers have a calming effect?

Answer 12

because when they are bound, they prevent the heart from beating too quickly

Question 13

Which two co-factors does tyrosine hydroxylase need in order to regulate DA synthesis?

Answer 13

1. O2 (oxygen)

2. BH4 (pteridine co-factor)

Question 14

If a receptor is presynaptic, what can we say about its function?

Answer 14

That it is presynaptic

Question 15

What do the DA autoreceptors do when too much DA is bound to the D2 autoreceptors?

Answer 15

They phosphorylate tyrosine hydroxylase

Question 16

What are 4 ways to control DA neurotransmission?

Answer 16

1. end product inhibition?
2. BH4 availability (BH4 must be synthesized)
3. DA autoreceptors phosphorylate TH
4. controlling the firing rate of DA neurons (increased firing causes TH to make more DA, which increases BH4 affinity)

Question 17

What are the two major DA pathways?

Answer 17

1. The nigrostriatal pathway

2. The mesocorticolimbic pathway

Question 18

Describe the nigrostriatal pathway.

Answer 18

Cell bodies lie in the substantia nigra and project to the dorsal striatum (aka caudate nucleus aka putamen)

Question 19

Describe the mesocorticolimbic pathway.

Answer 19

Cell bodies lie in the ventral tegmental area and project to the ventral striatum (aka nucleus accumbens) and the prefrontal cortex

Question 20

What effect do all psychostimulants have on the receptors they bind to?

Answer 20

They all act on the dopamine transporter, causing DAT to pump DA out instead of sucking it back in
- they also work on the NE transporter, and the 5-HT transporter (they have a higher affinity to NET than DAT)

Question 21

What is ADHD characterized by?

Answer 21

1. hyperactivity

2. attention deficits

Question 22

Which of dopamine’s two pathways is degenerated in Parkinson’s disease?

Answer 22

The nigrostriatal pathway (which is responsible for initiation of movement, habit learning, and motor learning

Question 23

What is the prefrontal cortex responsible for?

Answer 23

1. inhibition
2. working memory
3. executive function

Question 24

What did Patricia Goldman-Rakic research?

Answer 24

She gave administered DA agonists in the pfc to primates and observed an increase in memory deficits
- she also gave DA antagonists and observed the same memory deficits

Question 25

How can we describe the effect that DA has on working memory?

Answer 25

In terms of the Yerkes-Dodson law (not enough DA impairs memory, and too much DA does the same thing; there is a sweet spot of DA concentration where memory is at its peak)