17 Chemical Messengers and Excitotoxicity - M/A Flashcards Preview

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Flashcards in 17 Chemical Messengers and Excitotoxicity - M/A Deck (116)
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1

How do you identify if a neurotransmitter is fast or slow acting?

By the type of channel it activates; (ionotropic = fast, metabotrophic = slow)

2

Ionotropic receptors are what?

Gated ion channels that are opened by binding of ligand = ions flow; results in a quick effect

3

Metabotropic receptors are what?

receptors that work through a 2nd messenger system when activated = slow effect; i.e GPCRs

4

What are the 4 major types of receptor classes?

GPCRs, RTKs, Ligand-gated ICs, NTFRs

5

How is the signaling of neurotransmitters (NTs) terminated? 

  • reuptake
  • enzymatic degradation
  • diffusion away from the synapse
  • accumulation in glial cells 

6

What are the possible effects that an NT can have on its target receptor?

stimulator, inhibitor, or modulator

7

What ion is required for the exocytosis (release) of an NT from a presynaptic neuron?

Ca2+ 

8

What are the 5 major biogenic amines?

  1. Epi 
  2. norepi (NE)
  3. Dopa (DA)
  4. Histamine 
  5. Serotonin (5-HT)

9

What amino acid are catecholamines (Epi, NE, and Dopa) derived from?

tyrosine 

10

What is the rate-limiting step in catecholamine synthesis?

tyrosine --> L-dopa 

11

Which catecholamine is L-dopa converted into?

Tyrosine --> L-dopa--> Dopa-- >NE

12

What enzyme is needed to convert NE --> Epi?

phenylethanolamine N-methyltransferase (PNMT)

13

What are the 2 major enzymes in catecholamine production?

tyrosine hydroxylase and PNMT

 

14

That is the sequence of catecholamine synthesis 

15

Where does the conversion of dopamine --> NE occur?

in vesicles called chromaffin granules 

16

Where is NE --> Epi?

cytosol 

17

What moves Epi from the cytosol into vesicles?

VMATs

18

What are COMTs and MAOs?

enzymes that inactive catecholamines convert them into VMA 

19

What products of catecholamine metabolism is used to measure catecholamine production?

VMA 

20

Where are NE producing neurons found?

Locus coeruleus = crucial to waking up/awareness; projects to almost all areas of CNS 

 

21

Where is Epi primarily released?

adrenal medulla 

22

Where is dopamine made in the CNS?

substantia nigra (black substance) and ventral tegmental area of brain stem 

23

Where does the substantia nigra project to?

striatum (lentiform nuclei & caudate nuclei)

24

Where does the ventral tegmental area project is DA fibers to?

prefrontal cortex and parts of the limbic system 

25

What are the 4 major systems that use DA?

  1. substantia nigra = motor 
  2. mesolimbic = VTA --> Nucleus accumbens 
  3. mesocortical = VTA--> frontal cortex
  4. tuberinfundibular = hypothalamus --> anterior pituitary (prolatin suppression)

26

where is histamine made in the CNS?

the tuberomammillary nucleus (TMN) of the posterior hypothalamus; project throughout brain

27

What cognitive state is histamine associated with?

wakefulness

28

How does histamine down regulate itself?

activation of H3 receptors on presynaptic neuron says there is enough histamine 

29

Diamine oxidase degrades what?

histamine 

30

What nuclei make serotonin (5-HT)

raphe nuclei of the brainstem