Pharm- 11 Flashcards Preview

Clinical Neuroscience 2 > Pharm- 11 > Flashcards

Flashcards in Pharm- 11 Deck (78)
Loading flashcards...
1

Which sensations do A(delta) fibers transmit for pain?

myelinated transmit impulses much faster, used for first pain, noxious cold below 5 degrees C and injurious force on the skin

2

Which sensations do C-fibers transmit for pain?

nonmyelinated transmit impulses slower, used for second pain, temperatures above 45 degrees C and chemical and mechanical stimuli

3

Describe the pathway of pain peception from the periphery to the thalamus?

Impulses from the skin generated by the nociceptors activation are conducted to the dorsal horn of the spinal cord
In the dorsal horn the nociceptors form synapses with interneurons and second order neurons
Second order neurons travel in the lateral areas of the spinal cord (ALS from pain, temp crude touch), and project mainly to the thalamus

4

Where does the thalamus then project pain fibers in the CNS?

somatosensory Cx of the parietal lobe

5

Which fibers transmit the first pain signals?

transmitted by the Aδ fibers and is quick sharp (pinprick-like) in quality, and is perceived as highly localized on the body

6

Which fibers transmit the second pain signals?

transmitted by C-fibers and is slower to develop but longer lasting, feels dull, throbbing, or burning (the clap), and only diffusely localized, and endures after the stimulus ends

7

Are Aδ or C fibers more susceptible to local anesthetics?

8

Define analgesics

are specific inhibitors of pain pathways

9

How does codeine work?

signals the cell to increase K+ conductance in postsynaptic neurons and decrease Ca entry into presynatpic neurons --> double whammy decrease in NT action/release

10

What is local anesthesia?

- are nonspecific inhibitors of peripheral sensory (including pain), motor, and autonomic pathways

11

How does lidocaine work?

inhibits conductance of AP's in all afferent and efferent nerve fibers in the PNS

12

How do all local anesthetics block pain perception?

Inhibiting Na-channels --> prevents AP's on pain fibers

13

Procaine, tetracaine, and cocaine are example of what type of local anesthetics?

ester-linked

14

Lidocaine, prilocaine, bupivacaine, articaine, and EMLA are example of what types of local anesthetics?

amide-linked

15

What happens to ester-linked local anesthetics in the presence of water and esterases?

easily hydrolyzed to carboxylic acid and alcohol

16

Do amide or ester linked local anesthetics have a longer duration of action?

Amide LA's

17

What is the role of the aromatic group in the local anesthetic (LA)?

Hydrophobicity --> passage through cell membranes

18

What happens if there is too much hydrophobicity in the LA?

It's bad cuz the drug wont leave the hydrophobic interior of the cell --> continually acting

19

What are the 2 forms the amine group of the LA exist in?

protonated (+) or deprotonated (0)

20

What is the range of pKa for LAs?

8-10 (theyre weak bases)

21

So at physiological pH (7.4), are LA's protonated or unprotonated?

almost equal amts of both

22

Which form (+ or 0) crosses the cell membrane?

neutral form

23

Which form (+ or 0) binds stronger to the voltage-gated Na channel?

+ form

24

Procaine (novocain)- use

epidural for delivery, dentists

25

Procaine- plasma T1/2

low b/c of hydrophobicity and rapid removal

26

Procaine- potency

Low b/c of rapid dissociated from Na channel

27

Tetracaine- use

topical and spinal anesthesia

28

tetracaine- plasma T1/2

logn b/c of high hydrophobicity, can stay in tissues for a while

29

Tetracaine- potency

high because of high hydrophobicity and longer binding to Na channel

30

Cocaine- use

;-), mucosal and opthalmic local anesthetic, Dx of Horners