Pain

Question 1

What is Nociception?

Answer 1

A sensory process that provides the signals to trigger pain.

Question 2

What is phycological acute pain?

Answer 2

A warning device to damaging stimuli

Question 3

What stuff does phycological acute pain activate?

Answer 3

It activates nociception/ion channel complexes.

It activates chemicals and heat like TRPV1 and P2X3 receptors.

Mechanical - Ion channels.

Question 4

What is inflammatory pain?

Answer 4

Tissue damage and a release of mediators.
Temporary hypersensitivity at site and adjacent normal tissue.
Allodynia and Hyperalgesia.

Question 5

What is neuropathic pain?

Answer 5

Abnormal change in the tissue of the nervous system.
Permanent hypersensitivity at site and adjacent normal tissue.
Allodynia and hyperalgesia.

Question 6

What does the peripheral nervous system respond to?

Answer 6

Heat/cold
Chemical stimulation
Mechanical stimulation

Question 6

What are the ion channels with pain in the nociceptors?

Answer 6

Voltage gated ion channels
Voltage dependent Ca++ channels
K+ channels
Transient receptor potential channels (TRP)
Acid sensing ion channels (ASIC)
P2X and 5HT3

Question 7

What are the mediators generated by tissue damage?

Answer 7

Protons
Bradykinin
Nitric oxide
Nerve growth factor
5-HT
Inflammatory mediators like PG's, cytokines, histamines, ATP and adenosine.

Question 8

What is nociceptors activated by?

Answer 8

Bradykinin, 5-HT, Histamine, Prostaglandins, via separate receptors mechanisms.

Question 9

What are A sigma-fibres?

Answer 9

Myelinated fibres for transmission of sharp sensations/acute pain.

Question 10

What are C-fibres?

Answer 10

Unmyelinated fibres for conduction of slow pain/ache (SP).

Question 11

What are A beta-fibres?

Answer 11

Myelinated fibres for transmission of low intensity stimuli (touch, brush etc).

Question 12

What is Dorsal root ganglion?

Answer 12

Afferent transmission via DRG

Question 13

What is the neural mechanism of pain?

Answer 13

Fibres are entered into the spinal cord through the dorsal root and it ends in the grey matter of the grey horn.

Question 14

What are the central analgesic targets?

Answer 14

Opioid receptors - role in nociceptive transmission.

Substance P - transmitter in nociceptive afferent neurons.

5-HT - Important transmitter in inhibitory neurons from nucleus raphe
magnus to the dorsal horn.

NA - Important transmitter in inhibitory pathway from locus coeruleus
to the dorsal horn.

Question 15

What are the causes of neuropathic pain?

Answer 15

Lesion of somatosensory CNS
Diabetes (diabetic neuropathy)
Viral infection (Herpes virus, HIV)
Major surgery or trauma
Stroke
Spinal cord injury
Cancer
Chemotherapy (taxol, vincristine)
Inherited
Spontaneous
MS
Aging