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Flashcards in CNS Neurotransmitters Deck (61):
1

What are the monoamine neurotransmitters?

  • Norepinepherine (NE)
  • Serotonin (5-HT)
  • Acetylcholine (ACh)

2

What are the amino acid neurotransmitters?

  • Glutamate (Excitatory)
  • GABA (Inhibitory)
  • Glycine (Inhibitory)

3

What are the neuropeptide neurotransmitters?

  • Endorphin
  • Angiotensin
  • Substance P
  • Many others

4

What type of staining showed the nervous system was a collection of individual neurons?

Golgi staining

5

Describe the two types of transmission speeds and the charactestics of each.

  • Fast
    • Rapid, point-to-point, transient (doesn't last long)
    • Involve transmitter-gated ion channels (ionotropic)
    • Typicall triggered by a single depolarizatoin
  • Slow
    • Slow, diffuse, lasting
    • Involve G-protein coupled receptors (metabotropic)
    • Typically triggered by prolonged or repetative depolarization

6

What functional groups do monoamine neurotransmitters consist of? What is the exception to this?

  • Amine group connected to an aromatic ring by a two carbon chain
    • ACh is not a monoamine but is clumped together with this group

7

What enzyme converts glutamate (excitatory) to GABA (inhibitory)?

Glutamic acid decarboxylase (GAD)

  • Wherever there is glutamate, there is also GAD

8

What determines if a neuron is inhibitory or excitatory? What is the exception?

  • It's receptor
    • Gluatamate - Always excitatory
    • GABA - Always inhibitory

9

What neurotransmitters work together to tightly regulate different neural functions?

Glutamate & GABA

  1. Glutamate released into cleft
  2. Binds post-synpatic neurons
  3. Neurons can take up Glutamate and convert to GABA

10

What receptor is believed to be the source of learning?

Glutamate-NMDA receptor

11

Describe the Glutamate-NMDA recptor firing.

NMDA is a slective agonist to glutamata

  1. NMDA, Glutamate, and depolarization from -80mV to -40mV are required to fire
  2. Depolarization frees a Mg2+ that blocked channel
  3. Ca2+ influx results (Voltage gated)

12

What is synaptic plasticity?

Regulation of strength of connection between two synapses

  • Seen in Glutamate-NMDA receptor

13

What is glutamate toxicity?

Too much glutamate from:

  • Excessive gluatamate release
  • Poor glutamate reuptake

Excessive Ca2+ intake triggers neuronal injury/death

14

What can cause glutamate toxicity?

Stroke: Anoxia can release toxic amounts of glutamate

15

What is the mechanism of the GABAA receptor and what drugs act on it?

Hyperpolarization via Cl- influx into neuron

Drugs:

  • Benzodiazepines
  • Barbituates

16

What is the mechanism of the GABAB receptor and what drugs act on it?

Hyperpolarization via K+ outflux from neuron

Drugs:

  • GHB
  • Baclofen

17

What is the disease model for Huntington's?

Destruction of GABAergic neurons in basal ganglia

18

What is the disease model for Tetanus and Strychnine?

Inhibition of presynaptic GABA release (results in shortage of GABA in synaptic cleft)

19

What is the disease model in Stiff-Person Syndrome?

Antibodies destroy GAD and prevent GABA production, causing autoimmune or paraneoplastic syndrome

20

What drugs can treat excessive glutamate? (Increased glutamate can cause seizures)

  • Benzodiazepines (increase GABA efficiency)
  • Valproate (Inhibit enzymes that deactivate GABA)
  • Topiramate (Inhibit GABA re-uptake)

21

What are the side effects of treating excessive glutamate with GABA?

  • Sedation
  • Cognitive slowing

22

What are the non-therapeutic uses of drugs that increase GABA?

  • Anxiolysis, hypnosis, amnesia (occasionally)
  • High addictive potential
  • "Date-rape" drugs
    • GHB (Gamma-hydroxybutrate)
    • Benzodiazepines

 

23

What nuclei produce Dopamine?

  • Pars compacta (substantia nigra) - largest
  • Ventral tegmental area
  • Hypothalamus

24

Describe the Nigrostriatal tract.

  • Substania nigraStriatum (D2 receptors)
  • Regulates fluid and smooth muscle action

 

25

Describe the Mesolimbic tract.

  • Ventral tegmental areaN. accumbens (D1 receptors; part of limbic system)
  • Associated with fear & reward responses

26

Describe the mesocortical tract.

  • Ventral tegmental area Frontal lobe
  • Associated with motivation and response

27

Describe the Tubero-infundibular tract.

  • Hypothalamus → Pituitary
  • Regulates secretion of hormones, notably prolactin

28

What are the 4 clinically imporant tracts associated with dopamine?

  • Nigrostriatal tract
  • Mesolimbic tract
  • Mesocortical tract
  • Tubero-infundibular tract

29

Parkinson's disease is associated with death of what structures?

Pars compacta (within substantia nigra) - Decreased dopamine

30

What are the primary and secondary symptoms related to Parkinson's disease?

  • Primary: Movement-related disorders
    • Shaking, rigidity, slowness, difficulty with gait
    • Lack of DA to reach receptors to gait/initiate movements
  • Secondary: Cognitive disorders
    • Dementia, sensory, sleep, emotional lability

 

31

What illicit drugs block the re-uptake of Dopamine? What is the effect?

  • Cocaine and methamphetamine
  • Excessive dopamine can cause paranoia, hallucinations, delusions, disorganized thoughts
  • Results in reward dysfuntion

32

What can be used to treat Parkinsons (decreased dopamine)?

L-DOPA (bypasses rate limiting step of converting tyrosine to DOPA by tyrosine hydroxylase)

33

What are the neurotransmitters changes associated with depression and what can be used to treat it?

  • Decreased dopamine and serotonin
  • Buproprion/Methylphenidate (prevent DA re-uptake)

34

What are the neurotransmitter changes associated with ADHD and what drugs can be used to treat it?

  • Decreased dopamine and norepinepherine
  • Bupropion/Methylphenidate (prevent re-upatke of DA)

35

What are the neurotransmitter changes associated with Schizophrenia and what drugs can be used to treat it?

  • Increased dopamine
  • Antipsychotics (operate via D2 receptor antagonism)

36

What nucleis produce serotonin (5-HT)?

Raphe nucleus (pons/midbrain)

37

What tracts are associated with serotonin (5-HT)?

Many; extensive projections throughout brain including:

  • Cortex
  • Cerebellum
  • Hypothalamus
  • Spinal column
  • PNS

38

What disorders are associated with decreased serotonin?

  • Major depressive disorder
  • Anxiety disorders
  • Nausea (increased, not decreased)

39

What are the drugs used to treat major depressive disorder?

  • SSRIs
  • TCA
  • MAO inhibitors

40

What are the drugs used to treat anxiety disorders?

  • Benzodiazepines (DOC)
  • SSRIs
  • TCA
  • MAO inhibitors

41

What are the drugs used to treat nausea?

Ondansntron (5-HT3 receptor antagonist)

42

What is the rate limiting step in serotonin production?

Tryptophan → 5-HTP

TPH (Tryptophan hydroxylase)

43

What is serotonin syndrome and what are the symptoms?

  • Excessive serotonin
  • Cognitive symptoms: Headache delerium
  • Autonomic symptoms: Hyperthermia, hypertension
  • Somatic symptoms: Tremor, hyperreflexia, clonus

44

What drugs of abuse can causes serotonin disorders?

  • LSD
  • MDMA

45

What food and beverages can cause serotonin disorders?

  • Cheese (tyramine)
  • EtOH

46

What nuclei produce norepinepherine? What is it responsible for?

  • Locus ceruleus (pons)
  • Fight or flight response
  • Smooth muscle contraction or relaxation, heart muscle contraction, glycogenolysis

47

What tracts are associated with norepinepherine?

Broad projectsion throughout cortex (frontal), limbic, spinal

48

What neurotransmitter changes are associated with Parkinsons?

  • Decreased NE (locus ceruleus destruction) secondarily due to decreased DA (substania nigra destruction) - Must have dopamine to make NE
  • Increased 5-HT
  • Increased ACh

49

Panic attacks are associated with increased levels of what neurotransmitter?

Increased norepinepherine (due to re-uptake deficiency)

50

What drugs can be used to treat norepinepherine disorders?

  • Antidepressants (increase NE availability)
  • Selective NE/DA re-uptake inhibitor (Bupropion)
  • SSNRIs (Vanlafaxine, duloxetine)

51

What nucleus produces ACh?

  • Nucleus Basalis of Mynert (inferior to anterior commissure)
  • Pedunculopontine nucleus (brainstem, caudal to substantia nigra)

52

What tracts are associated with ACh?

Pedunculopontine - Projects to:

  1. Thalamus, basal ganglia
  2. Brainstem, deep cerebellar nuclei

Nucleus Basalis of Mynert - Projects to:

  1. Cortex, associated with memory, learning, defecits with Alzheimer's

Parasympathetic nervous system

  1. Heavily involved with limbic system and homeostasis

53

Alzheimer's disease is associated with what neurotransmitter changes?

  • Decreased ACh (degeneration of NBM)
  • Loss of nACh receptors in hippocampus

54

The hippocampus in normal, healthy adults is rich in what?

Nicotnic ACh receptors

Linked to cognition

55

Schizophrenia shows reduction of what type of receptors?

Nicotinic ACh receptors in hippocampus and frontal cortex

Cigarette smoking is commonly believed to be form of self-medicatoin

56

What is required for nictonic ACh receptors to fire?

  • ACh
  • Nicotine

57

What is required for muscarinic ACh receptors to fire?

  • ACh
  • Muscarine

58

What can cause ACh toxicity and what is used to treat it?

Organophosphates/Sarin gas

Atropine (anti-muscarinic)

59

What are the symptoms of ACh toxicity at nicotinic receptors?

SLUDGE

  • Salivation
  • Lacrimation
  • Urination
  • Defacation
  • GI upset
  • Emesis

60

What are the symptoms of too little ACh (anticholinergic toxicity) at muscarinic receptors?

  • Increased body temperature and sweating (hot as a hare)
  • Loss of accomidation (blind as a bat)
  • Decreased secretions (dry as a bone)
  • Disorientation from CNS manifestations (mad as a hatter)

 

61

What drugs can cause anticholinergic toxicity (too little ACh)?

  • Anti-nausea medications
  • Antidepressants
  • Antipsychotics
  • Anti-histaminics