Drugs affecting nerve excitability Flashcards Preview

Hugh's MD1 Neuro > Drugs affecting nerve excitability > Flashcards

Flashcards in Drugs affecting nerve excitability Deck (31):
1

T/F Both toxins and local anaesthetics bind extracellularly

False, local anaesthetics bind intracellularly

2

Are local anaesthetics more effective in basic or acidic environments?

Basic

3

What occurs with general anaesthetics?

Depression of cortal processes for pain/sensory signalling

3

What are barbiturates main effect?

Depression of the CNS

- sedation > surgical anaesthesia > coma > death

4

Which type of GABA receptors do benzodiazepines bind to?

GABA A receptors - Ligand gated ion channels

4

Are there dependence issues/withdrawal symptoms with benzodiazepines?

Yes

5

Why are some hydrophilic local anaesthetics dependent on nerve activity?

Because they bind to the inactivative state that the Na channels are in after a Na channel has been opened

7

What is the mechanism of action of local anaesthetics?

Reversible blockage of Na channels

7

What is clinical efficacy?

The strength of the beneficial effect

8

Which is faster acting, hydrophobic or hydrophilic local anaesthetics? Why?

Hydrophobic because they can diffuse through membranes and reach the intracellular domain

9

Which nerves will local anaesthetics affect in a given bit of tissue?

All of them!

10

What are the side effects of benzodiazepines?

Drowiness

Confusion

Loss of coordination

11

What is a common side effect of anxiolytics?

A degree of drowiness and sedation

12

What are benzodiazepines used for?

Epilepsy

Sleep disorders

Anxiety

Pre-surgical

Acute alcohol withdrawal

13

What are the physiological effects of benzodiazepines?

Sedation and induction of sleep

Amnesia

Muscle relaxant

Reduction of anxiety and anger

13

Why are benzodiazepines generally prefered to barbiturates?

Less central and cardiovascular effects

No overdose

Less dependence

14

How does benzodiazepine work in epilepsy?

It enhances the activity of GABA (inhibitory) receptors

15

What is potency?

The dose of drug required to elicit its effect

16

What is an example of a hydrophobic local anaesthetic?

Benzocaine

17

What are the 7 aspects of synaptic transmission that can be targeted by drugs?

Synthesis

Storage

Release

Inactivation

 - Reuptake

- Metabolism 

Receptor

18

What are the problems with barbiturates?

Toxic - low therapeutic window

- Induce liver enzymes

- Abrapt withdrawal causes death

Highly addictive

20

What is anxiety?

The manifestation of the fear response

22

Which is more sensitive to local anaesthetics, sensory or motor nerves?

Sensory

23

Are fast or slow acting local anaesthetics dependent on the level of use of a nerve?

Slow

25

What occurs in local anaesthetics?

Local inhibition of pain and sensory pathways

26

Describe the level of glutamate in epilepsy

There is too much of it (it's excitatory)

27

Describe the level of GABA in epilepsy?

There is too little of it (it's inhibitory)

28

How do barbiturates act on GABA receptors?

Prolong opening of the receptor

29

How does phenytoin act in epilepsy?

Blocks Na+ channels to inhibit excitability

- the channels must be open to be blocked, therefore the nerve must be active

30

What do benzodiazepines do to their target GABA receptor?

Increase it's rate of opening and closing

31

Why are sensory nerve more sensitive than motor nerves to local anaesthetic?

Because they are smaller