Toxicology Exam 1

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study to identify the specific target molecule which is attacked by a toxin

molecular mechanisms
Toxins may be

specific and non-specific
Example of a non-specific toxin

sulfuric acid
Direct effect

attack molecule of the retina resulting in blindness
Indirect effect

attack the pancrease resulting in diabetes
Direct targets of toxins
- Proteins
- Lipids
- Nucleic Acids
Proteins that may be targeted by toxins
- Enzymes
- Receptors/Ion Channels
- Transport Proteins
Enzymes that may be targeted by toxins
- Acetylcholine esterase
- Mitochondrial enzymes
Organophosphates
- methylparoxon
- ties up ACHE
Example of enzyme aging

ACHE-Phosphate loses a methyl group resuling in a fre --O
Three types of chemicals to help enzyme recovery
- Hydroxylamine
- Hydroxamic acid derivatives
- Oximes
- (all contain N-OH group)
Oximes
- Pralidoxime (2-PAM)
- more efficient than water to recover ACHE
Mitochondrial enzymes that may be targeted by toxins
- Cytochrome oxidase
- ATPase
Complex I of the respiratory chain deals with

NADH - linked molecules
Complex II of the mitochondrial respiratory chain deals with

FADH linked molecules
Inhibitor of Complex I (NADH complex)

rotenone
Amytal

barbituric acid derivative
Oligomycin

inhibitor of ATPase
Cyanide

inhibitor of cytochrome oxidase complex
Tetrodotoxin

sodium channel inhibitor
Effects of toxins on receptors/ion channels
- increased or decreased ions moving through the channels
- intracellular enzyme activity increased or reduced
- gene expression may be altered
Most abundant protein carrier in the body is
- hemoglobin
- carries oxygen
Oxidized form of iron

ferric
reduced form of iron

ferrous
CO binds heme ____x better than O

20
Oxidized iron in hemoglobin is called
- methemoglobin
- will not bind oxygen
- can sometimes be beneficial

Author

Rx2013

61153

Card Set

Toxicology Exam 1

Description

Dr. Badr's lecture 1/19

Updated

2011-01-21T22:22:43Z

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