3.8 Pain + Opioids

Question 1

What are the 3 types of primary afferent fibres?

Answer 1

1. Ab
2. Ad
3. C

Question 2

Which fibres are for physical pain?

Answer 2

Ad

Question 3

T/F: pain is only physical

Answer 3

False, emotional too

Question 4

What is an analgesic?

Answer 4

Selectively blocking pain only

Question 5

What is a local anesthetic?

Answer 5

Non-selectively blocking all sensation (including pain)

Question 6

What is a general anesthetic?

Answer 6

Cause unconciousness but not always analgesia

Question 7

What is allodynia?

Answer 7

Feel pain by a weak stimulus

Question 8

Persisting pain is carried by ___ fibres

Answer 8

C

Question 9

Acute pain is carried by ___ fibres

Answer 9

Ad

Question 10

Chronic pain is caused by the release of…?

Answer 10

Bradykinin, histamine, and PGs

Question 11

What is deep pain?

Answer 11

Non-localized pain caused by major traumas

Question 12

NSAIDs treat ___ pain

Answer 12

Mild, persistent, chronic pain

Question 13

Opioids treat ___ pain

Answer 13

Deep pain

Question 14

Which type of pain is ‘bad’ pain?

Answer 14

Neuropathic pain, disease of pain

Question 15

What is neuropathic pain?

Answer 15

Pain induced by nervous system disease, persisting despite healing of the original injury ending

Question 16

What is centralization of pain?

Answer 16

Untreated injury to periphery leads to CNS chronic pain

Question 17

What are the types of endogenous opioids?

Answer 17

Endorphins and enkephalins

Question 18

What are the types of endorphins?

Answer 18

1. Beta-endorphins
2. Dynorphins
3. Endomorphins

Question 19

What are the types of enkephalins?

Answer 19

Met and leu

Question 20

Opioid receptors are coupled to…?

Answer 20

GiCPRs

Question 21

What are the steps in the opioid receptor signalling pathway?

Answer 21

1. Gi-alpha –> -AC –> -cAMP
2. • K+ –> hyperpolarized –> -APs –> -pain
3. -N-type Ca2+ –> -APs –> -NTs –> -pain

Question 22

Where do endogenous opioids come from?

Answer 22

Periaqueductal grey (PAG)

Question 23

Opioid signalling goes from the PAG go to the…?

Answer 23

RVM (rostral ventral medulla) and dorsal horn

Question 24

Opioid signals in the RVM and dorsal horn cause…?

Answer 24

Decreased NT release

Question 25

The PAG and RVM descend into the ____ to inhibit pain

Answer 25

Substantia gelatinosa

Question 26

What do GABA neurons do?

Answer 26

They inhibit pain inhibiting neurons, causing pain

Question 27

Opioids ____ GABA neurons

Answer 27

Inhibit

Question 28

T/F: all opioids are antagonists

Answer 28

False, all agonists or partial agonists

Question 29

What are the 3 types of opioid receptors?

Answer 29

MOR, DOR, and KOR
miu, delta, kappa

Question 30

Which ORs cause analgesia?

Answer 30

MOR and KOR

Question 31

All ORs cause…

Answer 31

Sedation and fogginess

Question 32

Which ORs cause euphoria and peace?

Answer 32

MOR and DOR, dopamine linked

Question 33

Which ORs involve dopamine signalling?

Answer 33

MOR and DOR

Question 34

What are the major effects of opioids?

Answer 34

1. Analgesia
2. Sedation
3. Euphoria
4. Antitussive
5. Depression of respiratory centre
6. Nausea/vomiting

Question 35

Which ORs cause respiratory depression?

Answer 35

MOR

Question 36

How do opioids supress breathing in opioid overdose?

Answer 36

Repress prebotzinger complex (respiratory centre)