Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

MD1 Neuroscience > Regulating Neuronal Excitability > Flashcards

Regulating Neuronal Excitability Flashcards

(49 cards)

Start Studying
1
Q

What is an example of a neurotransmitter not stored in a vesicle?

A

NO

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What kind of inputs do motor nerves receive?

A

Excitatory

Inhibitory

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What happens in epilepsy?

A

Excessive discharge
Too little inhibition - get spasms
Too much excitation - excessive motor stimulatio

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What are the two neurotransmitters relevant to epilepsy?

A

GABA

Glutamate

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the best target for modulating inhibitory activity in epilepsy?

A

Enhance GABA receptor activity

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

How do benzodiazepines work?

A

Used to treat epilepsy
Enhance GABA receptor activity
Allosteric modulators
Increase GABA binding

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

How do you reduce excitatory input in epilepsy?

A 
Limit excitatory nerve activation
Inhibit T-type Ca channels
- Specific to some neurons
- More readily expressed on excitatory nerves
Inhibit NMDA receptor
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

Describe phenytoin

A

Used in treating epilepsy

Stops nerve action by inhibiting Na channels

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Describe ethosuximide

A

Inhibits T-type Ca channels

Stops vesicle release

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

Describe felbemate

A

Inhibits NMDA receptor

Enhances GABA receptor

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What else do many epileptic drugs cause?

A

Sedation; eg:
- Benzodiazepines
- Some others
Analgesia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are some examples of analgesics?

A

NSAIDs
Anti-pyuretics
Opioids

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

What is an analgesic?

A

Targets pain/sensory pathways
Sets threshold to determine what degree of excitation is sent to brain
Increases pain threshold

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What is a local anaesthetic?

A

Targets pain/sensory nerves as well as others in the region

No loss of consciousness

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What is a general anaesthetic?

A

Depresses cortical processing of pain/sensory signal
Causes loss of consciousness
Not regionalised

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Which drug category has the highest degree of selectivity?

a) Analgesics
b) Local anaesthetics
c) General anaesthetics

A

b) Local anaesthetics

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What was the first local anaesthetic?

A

Cocaine

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe local anaesthetic agents

A

Drugs that reversibly block conduction of nerve impulses at axonal membrane - influence action potential

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the weak base local anaesthetics?

A 
Aminoesters
- Eg: procaine
- Shorter acting
- Hydrolysis by choliesterases
Aminoamides
- Eg: lignocaine, bupivicaine, ropivicaine
- Longer acting = 1-1.5 hrs
- Hepatic metabolism
Benzocaine
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are examples of lethal toxins that share a target with local anaesthetics?

Study These Flashcards
A

Tetrodotoxin in puffer fish

Saxitoxin in dinoflagellates

21
Q

Describe the clinical use of local anaesthetics

Study These Flashcards
A

Safe
- Very specific binding to Na channel
- Reversible binding with no nerve damage
- Will affect all nerves/excitable tissues because Na channel fundamental to all excitable tissues
Local application to limit systemic distribution - makes them safe

22
Q

What are the effects if local anaesthetics act on non-sensory nerves?

Study These Flashcards
A 
Peripheral motor nerves
- Paralysis
Autonomic nerves
- Hypotension
- CNS convulsions
- Coma
Heart
- Anti-dysrhythmic
- Cardiac arrest
23
Q

What happens to the nerves with increasing concentrations of local anaesthetic?

Study These Flashcards
A

More sensory block
More motor block because drug reaches these fibres
More autonomic block

24
Q

What is the relative sensitivity of nerve types to local anaesthetics?

Study These Flashcards
A

Sensory > autonomic > motor

25
What is the site of interaction of local anaesthetics?
Intracellular transmembrane domain on Na channel
26
What is the difference in binding between local anaesthetics and toxins that share the same receptor target?
Local anaesthetics bind intracellularly and toxins bind extracellularly
27
What are the two mechanisms of action of local anaesthetics?
``` Hydrophobic - Faster - Non-use dependent - Eg: benzocaine Hydrophilic - Slower - Use dependent Eg: aminoesters, aminoamides - Mainly ionised at physiological pH ```
28
What determines the rate of onset/offset of local anaesthetics?
Rate of diffusion across membrane
29
Describe how hydrophobic local anaesthetics block the Na channel
Enter cell by diffusing across lipid membrane | Block gate like plug
30
Describe how hydrophilic local anaesthetics block the Na channel
Non-ionised form diffuses across membrane into cell Re-ionises Blocks channel in ionised form
31
What are the general properties of local anaesthetics?
Prevemt propagation of nerve action potential Small fibres more sensitive Stabilise axon membrane - No change in resting membrane potential Effect more pronounced in basic medium - Allows more drug to cross membrane Greater effect at high frequency
32
What happens when local anaesthetics are used during an infection?
Infection creates more acidic environment | Decreases effect of drug, therefore need higher concentration to get same effect as normal
33
What is the toxicity of local anaesthetics?
Generally safe Toxicity proportional to blood level - if they enter bloodstream Cardiovascular effects - Direct myocardial depression - Depression of vasomotor centre - Hypotension - except cocaine > causes hypertension instead Can cross BBB > CNS effects - Inhibitory fibres more sensitive > excitation - Tremor - Convulsion - Respiratory arrest
34
Are hypersensitivity reactions proportional to blood level?
No
35
Who can get hypersensitivity reactions to local anaesthetics?
Both patient and practitioner, as even handling drugs can cause development
36
Describe the topical application of local anaesthetics
Over the counter - Lozenge: throat drops containing benzocaine - Gels: generally poorly absorbed across skin and over inflamed areas because even though fibres exposed, at low pH - Contain very low concentrations of lignocaine - Menthol doing most of the work Professional use only - Eye drops: ocular procedures, often including a dye - Injection: specific procedural use; eg: IV lignocaine for dysrhythmia
37
What are the types of ways local anaesthetics are used when injected?
Infiltration: combination with vasoconstrictor prolongs action Nerve block: injection close to major nerves Epidural and intrathecal
38
What are the stages of anaesthesia?
``` Stage 1 - Amnesia - Euphoria Stage 2 - Excitement - Delirium - Resistance to handling Stage 3 - Unconsciousness - Regular respiration - Decreasing eye movement Stage 4 - Medullary depression - Respiratory arrest - Cardiac depression and arrest ```
39
How can general anesthetics be formulated?
Inhalation | IV
40
What does formulation of general anaesthetics influence?
Slight differences in pharmacokinetics
41
What are some inhaled general anaesthetics?
Desflurane Sevoflurane Isoflurane
42
What are some IV general anaesthetics?
Propofol | Thiopentone
43
What are the relevant pharmacokinetics for general anaesthetics?
``` Dose and duration of action Absorption - when inhaled Distribution - Vd - t1/2 - Get into compartments other than brain Metabolism Elimination - Kidneys - Liver - Lungs Drug interactions ```
44
What are the side effects of general anaesthetics?
``` Happen at final endpoint depression = stage 4 Respiratory - Impaired ventilation - Depression of respiratory centre - Obstruction of airways - Retention of secretions Cardiovascular - Decreased vasomotor centre function - Depress contractility - Peripheral vasodilation - Cardia arrythmias - Inadequate response to fall in BP or CO ```
45
What is given to counteract the retention of secretions that happens when a patient is given general anaesthetics?
Anti-muscarinics administered
46
What are the two theories on mechanism of action of general anaesthetics?
Lipid theory | Receptor interaction
47
What is the lipid theory in relation to mechanism of action of general anaesthetics?
Close correlation between anaesthetic potency and lipid solubility Anaesthesia caused by volume expansion of membrane lipids Effect can be reversed by pressure - pushed out of membranes
48
What is the receptor interaction in relation to mechanism of action of general anaesthetics?
Many anaesthetic agents inhibit excitatory receptors - Glutamate - NMDA Many anaesthetic agents enhance effects on inhibitory receptors - GABA - Glycine
49
What is an NMDA receptor agonist?
Ketamine

MD1 Neuroscience (55 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions