CNS Flashcards

1
Q

Which drugs can target the CNS directly without peripheral effects?

A

Morphine. receptor is on surface of spinal cord - can slip needle between vertebrate, cannula delivered epidural injection to deliver morphine post surgery
Drug to treat spasticity can also be given spinally

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

Which neurotransmitters are excitatory and inhibitory?

A
Glutamate is excitatory
Ach, NA, 5ht, DA mixed effects
Peptide substance P is excitatory
Opioids inhibitory
Nitric oxide and adenosine inhibitory
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What kinds of pathways is glutamate found in?

A

Often long pathways, neuron to neuron across body
periphery->cortex
often long term effects via receptors

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

Which receptor is overactive during a stroke?

A

NMDA
NMDA allows Na and Ca to enter, causing large bursts of activity.
Calcium entry brings water, osmotic pressure → cell death.
NO is increased. NO → free radicals → cell death

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

How are peptide neurotransmitters synthesised and transported?

A

Nuclear synthesis as large precursors/polypeptides, which are called pre-propeptides. These are then processed and cut down.
Peptide-containing vesicles are moved along microtubule “tracks” by ATP-requiring “motor” proteins such as kinesin. Microtubules are long, cylindrical filaments, 25 nm in diameter, present throughout neurons and other cells. This may be very slow.

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

With which other neurotransmitters do peptides coexist?

A

glutamate (sub P)
NA (NPY)
DA (CCK)

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

Are peptide nts uptaken?

A

No - they are broken down

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the therapeutic index of general anaesthetics?

A

4

side effects are mild to fatal eg respiratory depression

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

What are the 4 stages of general anaethesia?

A

1) analgesia
2) excitement/delirium
3) surgical anaethesia
4) respiratory depression, severe brainstem depression –> death

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

What are the 4 planes of surgical anaethesia?

A
  • eyes rolled, then fixed
  • corneal and laryngeal reflexes lost
  • pupil dilation and lost light reflex
  • intercostal paralysis, shallow amdominal respiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are some examples of intravenous general anaesthetics?

A

thiopentone, propofol, etomidate

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

What is the benefit of propofol?

A

no “hangover” so it enables day surgery after which patients can go home

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

What is the general structure of general anaesthetics?

A

there is no common structure. they are generally small and must be lipid soluble

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

Which features increase or decrease potency of a GA?

A

unsaturation increases potency
halogen substitution increases potency
ether group increases potency
hydrophilic groups decrease potency

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

What is the most accepted theory of mechanism of GAs?

A

they bind proteins having effect on neuronal function.

CNS is most sensitive - cortex first, brainstem later (which causes respiratory depression etc)

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

How does xenon affect NMDA Rs?

A

inhibits the glycine binding site of the NMDA R reducing its excitation

17
Q

Which receptor does halothane and propofol affect?

A

GABA-A

cause massive inhibitory potentiation

18
Q

What other effect do halothane and propofol cause?

A

increased current through 2 pore leak K channels (hyperpolarisation)

19
Q

What is a measurement of GA potency?

A

Minimum alveolar concentration/ MAC

The concentration in lungs required to prevent movement in 50% of patients in response to surgical stimulus ie pain

20
Q

What factors influence speed of induction/recovery of general anaesthetics?

A

Solubility in blood

Solubility in fats

21
Q

What are the features of ideal GA?

A

low MAC - high potency

low blood solubility - rapid onset and recovery

22
Q

What is remifentanil?

A

a potent, short-acting synthetic opioid analgesic drug given as adjunct to anaesthetic (propofol)

23
Q

What vehicle is used for propofol?

A

Cremophor EL –> anaphylactic reaction

now emulsion with soy oil, egg phospholipid, glycerol as tonicity-adjusting agent, NaOH to adjust pH

24
Q

What is carbamazepine used to treat?

A

epilepsy and pain

25
Q

How does Gabapentin work?

A

Gabapentin blocks calcium channels, treating pain

26
Q

Which receptors are recruited by “wind up” with chronic pain?

A

NMDA R

27
Q

What is heroin’s chemical name?

A

diacetylmorphine

28
Q

What are the names of the opioid receptors?

A

mu
delta
kappa
ORL-1

29
Q

What is Fentanyl?

A

rapid on/off opioid pain relief

30
Q

Which drug is an opioid antagonist?

A

Naloxone

31
Q

Are most opioid receptors pre or post synaptic?

A

75% are pre synaptic

32
Q

Is substance P excit or inhib?

A

excitatory

33
Q

Is nitric oxide excit or inhib?

A

inhibitory neurotransmitter