Drugs affecting nerve excitability

Question 1

4 things required for chemical neurotransmission

Answer 1

synthesis/storage
release
inactivation
receptors

Question 2

2 features of local anaesthetic? Where does it act?

Answer 2

regionalised
no loss of consciousness
acts peripheral nerve

Question 3

2 features of general anaesthetic?

Answer 3

non-regionalised
LOSS of consciousness
acts central cortex

Question 4

What happened with cocaine in the eye ball?

Answer 4

reversible numbness

Question 5

mechanism of action of local anaesthetic?

Answer 5

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

Question 6

aminoesters short or long acting? why? example?

Answer 6

procaine
shorter acting
due to hydrolysis by esterases

Question 7

aminoamides short or long acting? why? example?

Answer 7

long acting
lignocaine, bupivi/ropivi-caine
hepatic metabolism

Question 8

Is Benzocaine an aminoester? or aminoamide?

Answer 8

neither, is its own class

Question 9

local anaesthetic affect any nerve?

Answer 9

yes depending on dose (determines effect)

Question 10

nerve damage with local anaesthetic?

Answer 10

Nope. Reversible binding

Question 11

sensory or motor knocked out first with epidural anaesthetics?

Answer 11

sensory first, then motor slowly

Question 12

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

Answer 12

anaesthetic: intracellular
toxins: extracellular

Question 13

2 mechanisms of anaesthetic interaction with membrane Na+ channel?

Answer 13

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

Question 14

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

Answer 14

hydrophobic

fast acting non use dependent

Question 15

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

Answer 15

hydrophilic

slow acting, use dependent

Question 16

why chew lime with cocaine leaves?

Answer 16

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

Question 17

sensory fibers small or large?

Answer 17

small

sensory>ANS>motor

Question 18

what does local anaesthetic do to axon membrane?

Answer 18

stabilize resting membrane potential

Question 19

local anaesthetic better or worse in basic medium?

Answer 19

basic

Question 20

better to have charged or uncharged species for local anaesthetic?

Answer 20

both essential

uncharged more active

Question 21

is hypersensitivity to local anaesthetic proportional to blood level?

Answer 21

Nope, small amount cause big reaction

Question 22

too much local anaesthetic does what to cardiovascular system?

Answer 22

myocardial depression
vasomotor centre depression
hypotension

Question 23

cocaine cause hypotension?

Answer 23

Nope

Question 24

too much local anaesthetic does what to CNS system?

Answer 24

excitation
tremor
convulsion
respiratory arrest

Question 25

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

Answer 25

More because pH lower d/t inflammation

Question 26

4 stages of general anaesthetics?

Answer 26

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

Question 27

2 ways to administer general anaesthetics?

Answer 27

inhalation

intravenous

Question 28

2 big side effects of general anaesthetic?

Answer 28

respiratory

Cardiovascular

Question 29

what is lipid theory of pharmacodynamics of general anaesthetics?

Answer 29

1. correlation b/n anaesthetic and lipid solubility

2. meyer-overton: volume expansion of membrane lipids

Question 30

can you reverse general anaesthetic via pressure?

Answer 30

yes in hyperbaric chamber

Question 31

what is receptor interaction theory pharmacodynamics of general anaesthetics?

Answer 31

inhibit excitatory receptors like glutamate

enhance inhibitory receptors like GABA

Question 32

what class of drugs enhance GABA?

Answer 32

benzodiazepines

Question 33

3 ways to reduce excitatory glutamate?

Answer 33

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