Pain Neuro Lecture 2: Peripheral Sensitization

What is the common inflammatory dental pain condition that dentists encounter?

Pulpitis

What is the common musculoskeletal pain condition that dentists encounter?

Temporomandibular disorders

What is the common neuropathic pain condition that dentists encounter?

Trigeminal neuralgia

What is the term for increased pain from a stimulus that normally provokes pain?

Hyperalgesia

What is the term for pain due to a stimulus that does not normally provoke pain?

Allodynia

What is the term for the absence of pain in response to a usually painful stimulation?

Analgesia

What is the term for a burn injury lowering the pain threshold to amplify pain to noxious heat?

Thermal hyperalgesia

What is the term for the increased responsiveness of nociceptive neurons to their normal input?

Sensitization

Responses to what is recruited in sensitization?

Subthreshold inputs

How do inflammatory mediators affect nociceptors?

Sensitizes

What does peripheral sensitization act as for hyperalgeisa?

Neural substrate

What are the four steps of nociceptor signaling?

1. Transduction

2. Action potential initiation

3. Propagation

4. Neurotransmitter release

At which step of nociceptor signaling can sensitization occur?

All

What channel on nociceptors are opened by protons to lead to depolarization?

ASIC3

What type of signaling do inflammatory mediators use to sensitize nociceptors?

Gq-coupled receptor signaling

What are the lipid-like compounds that promote nociceptor signaling?

Prostaglandins

What type of medication prevents nociceptor sensitization by reducing prostaglandins?

NSAIDs

For what three reasons are local anesthesia less effective in inflamed tissue?

1. Acidic pH

2. Increased excitibility

3. Increased tissue blood flow

What is the pain caused when the sensory nerve itself is injured or diseased?

Peripheral neuropathic pain

What are the two trigeminal nerve branches that are commonly affected by dental procedures?

1. Inferior alveolar nerve

2. Lingual nerve

What are the disorganized axonal sprouts that form during axon regeneration?

Neuroma

Does removing injured afferent input abolish hyperalgesia?

No

What is the spontaneous activity developed by nociceptors for neuropathic pain?

Ectopic firing

What type of degeneration is triggered by injury on nociceptors?

Wallerian degeneration

What is created by Wallerian degeneration and glial cells to sensitize nociceptors?

Pro-nociceptive milieu