TOXICODYNAMICS Flashcards

1
Q

Mechanism of action of tetradotoxin

A

Blocks VG sodium channels of motor neurons causing skeletal muscle paralysis

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2
Q

Mechanism of action of 2,4-dinitrophenol

A

Collapses mitochondrial proton gradient across the inner membrane causing seizures and hyperthermia

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3
Q

Attributes of target molecule

A

Reactivity
Accessibility
Critical function

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4
Q

Reaction types

A

Noncovalent
Covalent
Hydrogen abstraction
Electron transfer
Enzymatic reaction

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5
Q

Target of CCL4

A

Destroys cytochrome p450 enzymes which catalyzes its own activation

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6
Q

Benefits of plasma cholinesterase binding to organophosphate

A

Counteracts the phosphorylation of acetylcholinesterase

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7
Q

Examples of noncovalent bonding

A

Strychnine - Glycine receptor on motor neurons in the spinal cord

TCDD to Aryl hydrocarbon receptor

Saxitoxin to Sodium channels

Phorbol esters to PKC

Warfarin to Vit K 2,3- epoxide reductase

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8
Q

Examples of soft électrophiles

A

Silver
Mercury
Carbon in polarized double bonds

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9
Q

Examples of hard electrophiles

A

Lithium
Calcium
Barium
Alkyl carbonizing ions
Benzylic carbonizing ions, nitrenium ions

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10
Q

Électrophiles that are neither hard not soft

A

Chromium , zinc, lead
Aryl carbonium ions

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11
Q

Examples of hard nucleophiles

A

Sulfur in thiols
Sulfur in methionine

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12
Q

Examples of hard nucleophiles

A

Phosphate oxygen in nucleus acids
Oxygen of purines and pyrimidines in nucleus acids

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13
Q

Nucleophiles that are neither hard nor soft

A

Mostly nitrogen containing
Nitrogen in primary and secondary amino groups of proteins
Nitrogen in amino groups in purine bases in niçois acids

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14
Q

Which toxicants abstract hydrogen

A

Neutral free radicals

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15
Q

What is the first step in DNA cleavage

A

Abstraction of H from deoxyribose in DNA to yield the C-4 radical

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16
Q

Toxication reactions that involve hydrogen abstraction

A

Nitration of tyrosine residues in proteins
Lipid peroxidation
DNA cleavage by hydrogen abstraction

17
Q

Toxication reactions involving enzymatic reactions

A

Ricin and Abrin hydrolyse ribisomal RNA and block protein synthesis

Botulinum toxin acts as a Zn-protease and prevent exocytosis of acetylcholine by hydrolysing the proteins responsible for the process

Anthrax also acts as a Zn protease and inactivate MAPKK inducing death

Diphtheria toxin blocks function of elongation factor 2 in protein synthesis

Cholera toxin activates a G protein

Snake venoms

18
Q

Bacterial toxins that catalyse transfer for ADP-ribose from NAD+ to specific proteins

A

Diphtheria
Cholera

19
Q

Toxins that inhibit closure of voltage activated Na channels

A

DDT
Pyrethroids

20
Q

Toxins impair tubulin function

A

Vinblastine
Colchicine
Paclitaxel
Arsénite

21
Q

Toxins that impair the function of actin

A

Cytochalasin B
Phalloidin

22
Q

Difference between sympathomimetic and anticholinergic toxidromes

A

Sympathomimetics cause sweating but anticholinergics do not