CNS Drugs Flashcards

1
Q

What are 4 types of ion channels and how do they affect ion influx and interact?

A
  1. V-gated channels: only open if there are certain conditions met in terms of ion balance across the membrane, very important in action potentials
  2. Ligand-gated (ionotropic) - don’t depend on ion concentration, depends on presence/absence of a ligand which binds a specific receptor
  3. Membrane delimited metabotropic ion channel - act through G protein
  4. Diffusable second messenger metabotropic ion channel
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2
Q

What drug is a Na channel blocker?

A

Tetrodotoxin (puffer fish)

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3
Q

What drug is an nACH receptor antagonist?

A

alpha-bungarotoxin (marine snake venom)

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4
Q

What drug is a GABAa receptor antagonist?

A

Picrotoxin (South Pacific plant)

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5
Q

What drug is a glycine receptor antagonist?

A

Strychnine (Indian plant)

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6
Q

What receptor do barbituates act on and what do they do?

A

Barbituates are GABAa receptor agonists and allow chloride to enter and hyperpolarize the cell, causing it to relax. Barbituates are anti-anxiety drugs?

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7
Q

What is a glutamine antagonist that acts as an antidepressant?

A

Ketamine

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8
Q

What are 3 ways to prolong the NT effect in the synaptic cleft?

A
  1. block reuptake transport to prevent NT reuptake
  2. prevent degradation by inhibiting the enzyme that metabolizes NT
  3. stimulate more release of the NT
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9
Q

What is the main nucleus in the brain that produces NE?

A

locus coeruleus

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10
Q

Describe teh order of metabolism of the 3 catecholamines.

A

tyrosine –> L-DOPA –> dopamine –> NE –> Epi

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11
Q

What are 3 selective NE reuptake inhibitors (SNRIs)?

A
  1. Desipramine
  2. Maprotyline
  3. Protryptiline
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12
Q

What is a drug of abuse that blocks NE reptake so that it remains in the synaptic cleft longer?

A

cocaine

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13
Q

What are 3 dopaminergic pathways and what are their neuronal tract projections?

A
  1. Nigrostriatal - nucleus in substantia nigra and projects to striatum –> pathology: Parkinson’s
  2. Mesolimbic - projects to limbic area particularly nucleus acumbens in teh ventral tegmental area of the midbrain (VTA) –> pathology: psychosis
  3. Tuberoinfundibular - cell bodies in infundibulum send projections into the pituitary hypophysis –> inhibitory control of PRL release
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14
Q

What is the precursor of dopamine used for Parkinson’s disease and the enzyme inhibitor that is often combined with it?

A

L-dopa is the precursor to dopamine and carbidopa is the inhibitor

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15
Q

What kind of drugs are anti-psychotics and what are 3 examples of these types of drugs?

A
  • Anti-psychotics are DA2 receptor antagonists
    1. spiroperidol
    2. primozide
    3. haloperidol
  • this are phenothiazines
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16
Q

What is the primary nucleus for 5H2 and what are its projections?

A

raphe magnus produces 5H2 (serotonin) and it projects to the hypothalamus and cortex

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17
Q

What kind of neurons are GABA NTs produced in?

A

short interneurons

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18
Q

What does GABA bind to and what does binding cause. Give an example of GABA agonists.

A

GABA binds to GABAa receptors which cause Cl- to come into the cell and hyperpolarize the cell.
*i.e. barbituates are GABA agonists, like phenobarbitol

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19
Q

Give an example of a benzodiazepine and describe how it acts.

A

Valium is a benzodiazepine and increases Cl- entry into the cell in the presence of GABA; it is not a GABA agonist on its own

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20
Q

What part of the brain contains CSF?

A

3rd ventricle

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21
Q

What NT pathways have C designations?

22
Q

What NT pathways have A designations?

23
Q

What part of the brain is responsible for strong emotions such as anger and fear and couples with hippocampus in intense events?

24
Q

What is the amino acid precursor for catecholamines?

25
What are 3 drugs that act on NE?
1. Cocaine 2. Rauwolfia alkaloids 3. Guanethedine
26
What drug of abuse acting on NE acts as an NE reuptake transporter blocker?
Cocaine
27
What drug acting on NE release NE by disrupting synaptic vesicle transporters?
Rauwolfia alkaloids
28
What drug acting on NE is used for HTN and inhibits release of NE from nerve endings and is taken up into sympathetic nerves by NE transporters?
Guanethedine
29
Describe the acute vs. chronic effects of cocaine use.
- Acute effect of cocaine - blocks reuptake sites and leads to a lot of DA in synaptic cleft. system detects it as an overstimulation and slows down production of DA - Chronic effect of cocaine - when cocaine is no longer there, DA is released less so that there is not even a normal level of DA at resting levels which leads to cocaine addiction
30
A 54yo woman is taking the SNRI maprotiline for her depression. It is workign well adn alleviating her problem. Her family physician, unaware of this previous drug use, prescribes guanethedine for her newly diagnosed hypertension. Is there any problem with this?
Yes- guanethedine blocks NE release and maprotilline blocks NE reuptake. These effects counteract each other, so guanethedine woudl not be effective.
31
What are 3 nuclei in the brain that produce dopamine?
1. VTA 2. Substantia Nigra 3. Tuberoinfundibular
32
Describe the Tubuloinfudibular Pathway
neurohypophysis to median eminence
33
Describe the Nigrostriatal Pathway
substantia nigra to caudate/putamen
34
Describe the Mesolimbic pathway
VTA and substantia nigra to nucleus accumbens
35
What structure at the base of the hypothalamus is associated with the anterior pituitary and portal system, and what catecholamine can act on this structure?
median eminence | -DA can act on it to inhibit PRL release
36
What disease is constitued by loss of 80% of nigrostriatal DA NTs?
Parkinson's disease
37
What pathology is associated with disturbance of the mesolimbic pathway?
psychosis
38
What 2 stimulants release DA?
amphetamine and methamphetamine
39
What does the enzyme carbidopa inhibit?
dopa decarboxylase
40
What is the name of the drug that contains the L-dopa precursor along with carbidopa for Tx of Parkinson's disease?
Sinemet
41
What are 3 main projection sites for serotonin?
1. hypothalamus 2. cortex 3. subiculum
42
What are 8 drugs that act as serotonin reuptake inhibitors?
1. fluoxetine 2. escitalopram 3. fluvoxamine 4. paroxetine 5. trazodone 6. imipramine 7. methysergide 8. LSD
43
ACh receptor subtype and agonist
M1; muscarine
44
DA receptor subtype and agonist
D1 or D2; bromocriptine
45
GABA receptor subtype and agonist
GABAa; muscimol; barbituates
46
Glutamate receptor subtype and agonist
NMDA
47
Glycine receptor subtype and agonist
Taurine, B-alanine
48
Serotonin receptor subtype and agonist
5HT1a; LSD
49
A 28 yo man is psychotic and taking Haloperidol. This man takes Parkinson's disease. Should he continue taking Haldol?
Haldol is a DA2 receptor antagonist. It can cause Parkinson's because drugs do not distinguish between the pathways, so it is blocking DA in substantia nigra and causing Parkinson's Syndrome in pits. Syndrome is reversible. Syndrome - blocking activity Disease - cells are actually dying
50
What should be given to pts for Parkinson's?
give L-Dopa to pt for Parkinson's because it stimulates DA2 receptors, but Haldol blocks it
51
In addition to Parkinson's Syndrome due to medication for psychosis, a pt has noticed milk dripping from his nipples?
Haldol is blocking DA which is the inhibitor of PRL. By blocking the action of DA, you are blocking inhibition of PRL which stimulates milk production. Tuberoinfundibular pathways timulates this
52
What kind of drugs act on GABA?
Barbituates bind to GABA site and act like an agonist to increase the Cl- and leads to hyperpolarization. Benzodiazepines like valium and librium bind to another site on GABAa receptor and increase Cl- influx in the presence of GABA.