Chapter 8 Poison Medicine Pharmacology Flashcards
drug
chemical that in small amounts has a significant effect on body function
pharmacology
scientific study of drugs, their origins, compositions, and effects on the body
Paracelsus
16th century Swiss physician and alchemist who said “Everything is a poison” (anything is a poison, dosage is important)
Tetrodotoxin (TTX)
poisonous substance found in puffer fish, tropical and semitropical oceans, salamanders, newts, octopus
made by bacteria living symbiotically within the animal species found to possess it
sticks to outside surface of voltage gated sodium channel (blocks pore through which sodium ions pass which prevents neurons from sending signals)
affects peripheral nervous system (does not get into heart because different molecular type or the brain because blood brain barrier)
symptoms: numbness, muscle weakness, paralysis, death (by respiratory paralysis and resulting suffocation)
treatment: artificial respiration until poison wears off
blood brain barrier
construction of blood vessels within central nervous system to regulate passage of material from blood to brain and vice versa
can cross barrier via transporter proteins or dissolving through blood vessel cell walls (must be hydrophobic/lipophilic)
TTX Resistance
results from mutation that changes only a single amino acid in the voltage gated Na+ channel (prevents TTX from blocking the Na+ channel)
Saxitoxin (STX)
molecule found in dinoflagellates (humans exposed to STX via consumption of shellfish)
blocks Na+ channels in a similar way to TTX (with same effects on peripheral nervous system)
STX Resistance
amino acid change from glutamic acid to aspartic acid
Paralytic shellfish poisoning (PSP)
medical condition resulting from STX poisoning
symptoms: numbness, muscle weakness, paralysis, death (respiratory paralysis and suffocation)
hydrophilic (does not cross blood brain barrier)
Batrachotoxins (BTX)
ultimate source unknown
prevent Na+ channel from closing (continusous flow of Na+ means cannot generate action potential)
results similar to that of TTX and STX
Anesthesia
loss of sensation
general anesthetics
chemicals that produce a global loss of sensation over the entire body
impacts the brain to produce a change in consciousness that affects all perception
Local anesthetics
chemicals that produce a loss of sensation locally (only in the region of the body near where they have been applied)
by the time the chemical enters the blood stream and spreads to other parts of the body, its concentration becomes too low to have any noticeable effect
Cocaine
first local anesthetic chemical to be appreciated by modern science
purified from coca plant Erythroxylum coca
binds to voltage gated Na+ channels, disrupts ability to open/close channel which results in reduction in signals from neurons sending sensory information to brain
acetylcholine (ACh)
neurotransmitter
corresponding receptor: AChR
