Drugs affecting nerve excitability Flashcards Preview

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Flashcards in Drugs affecting nerve excitability Deck (33):
1

4 things required for chemical neurotransmission

synthesis/storage
release
inactivation
receptors

2

2 features of local anaesthetic? Where does it act?

regionalised
no loss of consciousness
acts peripheral nerve

3

2 features of general anaesthetic?

non-regionalised
LOSS of consciousness
acts central cortex

4

What happened with cocaine in the eye ball?

reversible numbness

5

mechanism of action of local anaesthetic?

reversibly block conduction of nerve impulses at axonal membrane via binding of Na+ channel

6

aminoesters short or long acting? why? example?

procaine
shorter acting
due to hydrolysis by esterases

7

aminoamides short or long acting? why? example?

long acting
lignocaine, bupivi/ropivi-caine
hepatic metabolism

8

Is Benzocaine an aminoester? or aminoamide?

neither, is its own class

9

local anaesthetic affect any nerve?

yes depending on dose (determines effect)

10

nerve damage with local anaesthetic?

Nope. Reversible binding

11

sensory or motor knocked out first with epidural anaesthetics?

sensory first, then motor slowly

12

Where does local anaesthetic bind on sodium channel compared to toxins?

anaesthetic: intracellular
toxins: extracellular

13

2 mechanisms of anaesthetic interaction with membrane Na+ channel?

hydrophobic: fast, non use dependent
hydrophilic: slow, use dependent

14

benzocaine is hydrophilic or phobic? fast or slow? properties?

hydrophobic
fast acting non use dependent

15

aminoesters and amino amides is hydrophilic or phobic? fast or slow? properties?

hydrophilic
slow acting, use dependent

16

why chew lime with cocaine leaves?

acid helps to neutralize the basic flavour and helps with increased absorption into membrane

17

sensory fibers small or large?

small
sensory>ANS>motor

18

what does local anaesthetic do to axon membrane?

stabilize resting membrane potential

19

local anaesthetic better or worse in basic medium?

basic

20

better to have charged or uncharged species for local anaesthetic?

both essential
uncharged more active

21

is hypersensitivity to local anaesthetic proportional to blood level?

Nope, small amount cause big reaction

22

too much local anaesthetic does what to cardiovascular system?

myocardial depression
vasomotor centre depression
hypotension

23

cocaine cause hypotension?

Nope

24

too much local anaesthetic does what to CNS system?

excitation
tremor
convulsion
respiratory arrest

25

people with more trauma and inflammation need more or less anesthetic?

More because pH lower d/t inflammation

26

4 stages of general anaesthetics?

1. amnesia,euphoria
2. excitement
3. surgical anaesthesia
4. medullary depression

27

2 ways to administer general anaesthetics?

inhalation
intravenous

28

2 big side effects of general anaesthetic?

respiratory
Cardiovascular

29

what is lipid theory of pharmacodynamics of general anaesthetics?

1. correlation b/n anaesthetic and lipid solubility
2. meyer-overton: volume expansion of membrane lipids

30

can you reverse general anaesthetic via pressure?

yes in hyperbaric chamber

31

what is receptor interaction theory pharmacodynamics of general anaesthetics?

inhibit excitatory receptors like glutamate
enhance inhibitory receptors like GABA

32

what class of drugs enhance GABA?

benzodiazepines

33

3 ways to reduce excitatory glutamate?

1. limit nerve activation
2. inhibit T-type Ca2+channels
3. inhibit NMDA receptor