Pain

Question 1

where does pain transmission and processing occur

Answer 1

Peripheral - at site of injury

Central - spinal dorsal horn; midbrain and cortex

Question 2

Pathway of pain transmission

Answer 2

nociceptor -> DRG -> spinal cord -> processed -> relayed to brain

Question 3

What are nociceptive fibers

Answer 3

nerve fibers located in skin and deep tissue that detect pain (not called pain until brain registers it as pain)

Question 4

Two types of nociceptive fibers

Answer 4

A-delta and C-fibers

Question 5

A-delta fibers

Answer 5

myelinated, fast conducting, involved in 1st pain sensation

Question 6

C-fibers

Answer 6

non-myelinated, slower conducting, involved in 2nd/continuous pain sensation

Question 7

Do A-delta and C-fibers go to the brain?

Answer 7

NO. Only located in periphery. Cell bodies located in DRG

Question 8

Pain travels through _____ and causes the release of _____ in the _______

Answer 8

1. nociceptive fibers
2. neurotransmitters
3. spinal cord

Question 9

Primary neurotransmitters released into the spinal cord upon activation of nociceptive fibers

Answer 9

Glutamate and Substance P

Question 10

What does NT release activate

Answer 10

projection neurons of spinal cord

Question 11

Is glutamate excitatory or inhibitory

Answer 11

excitatory

Question 12

Main neuronal pathway involved in nociceptive transmission from spinal cord to brain

Answer 12

spinothalamic pathway

Question 13

where do projection neurons from spinal cord send information

Answer 13

to the brain

Question 14

Pathway of pain processing in the brain

Answer 14

Ascending pathway: signal goes to primary somatic sensory cortex -> homunculous, lets the brain know where pain is coming from –> projection neurons stimulate specific parts of the brain.

Question 15

what is the primary sensory cortex involved in

Answer 15

awareness of pain

Question 16

what is the amygdala involved in

Answer 16

affective components of pain (emotional aspect)

Question 17

what part of the brain is constantly activated in chronic pain

Answer 17

the amydala

Question 18

the descending pain pathway is also known as the

Answer 18

bulbospinal pathway

Question 19

The descending patheway consists of several synaptic connections where in brain (2)

Answer 19

midbrain and brainstem

Question 20

prominent NT of descending pathway (2)

Answer 20

NE and 5HT

Question 21

What is the mechanism by which you can inhibit pain

Answer 21

descending pathway

Question 22

where are NT and 5HT released

Answer 22

spinal cord

Question 23

descending pathway

Answer 23

cell bodies in brain release NE and 5HT into spinal cord –> make synaptic connection with interneuron –> interneuron synapses with projection neuron and releases NE and enkephalin –> this inhibits projection neuron –> stops pain transmission

Question 24

NT with inhibitory effect

Answer 24

NE, 5HT, Enkephalin

Question 25

Nociception

Answer 25

physiological perception of pain

Question 26

hyperalgesia

Answer 26

enhanced sensitivity to painful stimuli

Question 27

allodynia

Answer 27

enhanced sensitivity to non-painful stimuli

Question 28

What causes peripheral sensitization

Answer 28

A-delta and C-fibers

Question 29

What causes central sensitization

Answer 29

neurons in spinal cord

Question 30

peripheral sensitization pathway

Answer 30

1. tissue damage 2. prostaglandins (PG) and bradykinin )BK) released 3. this stimulates release of substance P from local fibers --> causes MORE release of PG, BK, histamine, 5HT, etc. 4. Leads to sensitization of nociceptive fibers: sensitized fibers transmit more intense messages to spinal cord; fire multiple AP; can contribute to primary hyperalgesia

Question 31

central sensitization pathway

Answer 31

1. projection neurons sensitized when large amts of glutamate and substance P constantly released. 2. sensitization of neurons in the spinal dorsal horn magnify pain signal to brain

Question 32

what receptors are believed to play a role in central sensitization

Answer 32

NMDA

Question 33

Can you have central sensitization without first having peripheral sensitization

Answer 33

No

Question 34

What lasts longer: central or peripheral sensitization

Answer 34

central

Question 35

does central sensitization always occur?

Answer 35

No - depends on severity of injury

Question 36

Primary and secondary hyperalgesia are due to central sensitization

Answer 36

True

Question 37

What is neurokinin receptor 1 (NK1r)

Answer 37

player in central sensitization | activated by substance P

Question 38

What do interneurons release

Answer 38

Enkephalin and NE

Question 39

Describe the tissue inflammation pathway

Answer 39

Injury -> PLA2 activation leads to increase in AA -> COX and AA released -> increases PG release -> increases PG -> terminal sensitization and pro-inflammation

Question 40

What to block to treat pain

Answer 40

block enzymes that convert AA to PG --> COX 1 and 2

Question 41

Does COX 1 or 2 have minimal constitutive activity

Answer 41

COX 2

Question 42

Inhibitors of Cox 1 and 2

Answer 42

``` Acetylsalacylic Acid (Aspirin) Ibuprofen (Advil) Naproxen (Aleve) Ketoprofen Indomethacin Ketorolac (Toradol) Meloxicam (Mobic) ```

Question 43

NSAIDs with LOW potency and FAST elimination

Answer 43

``` Acetylsalacylic Acid (Aspirin) Ibuprofen ```

Question 44

NSAIDs with INTERMEDIATE potency and INTERMEDIATE elimination

Answer 44

Naproxen (Aleve)

Question 45

NSAIDs with HIGH potency and FAST elimination

Answer 45

Ketoprofen Indomethacin Ketorolac

Question 46

NSAIDs with HIGH potency and SLOW elimination

Answer 46

Meloxicam

Question 47

Which NSAID is most selective for COX 2

Answer 47

Meloxicam

Question 48

Selective COX-2 inhibitors

Answer 48

Celecoxib (Celebrex) Valdecoxib (Bextra) -> off market Rofecoxib (Vioxx) -> off market

Question 49

COX 1 and 2 inhibitors SE profile

Answer 49

Lung: can exacerbate asthma sx (esp aspirin) Stomach: can induce ulcers and stomach bleeds (mainly COX1 property) Platelets: inhibits platelet aggregation (good for pt at risk for clots) Anti-coagulant properties -> can be good or bad

Question 50

Selective Cox 2 inhibitors SE profile

Answer 50

just as effective as COX1/2 inhibitors in reducing pain reduced risk of ulcers and modest decrease in stomach bleeds no effect on platelet aggregation no long term use risk

Question 51

Para-aetylaminopenol

Answer 51

Acetaminophen (Tylenol)

Question 52

Is Tylenol an NSAID

Answer 52

NO! It is an analgesic/antipyertic

Question 53

What does acetominophen increase?

Answer 53

endogenous NT

Question 54

What can disable acetominophens anti-inflammatory properties

Answer 54

peroxidases