Flashcards in Pain lecture 2 Deck (52):
What are pain tranducers known as?
What are the different types of nociceptors?
What are mechanical subtypes of nociceptors?
What are the receptor types for nociceptors?
-Transient receptor potential
-Prostaglandin/purino and pyrimidine receptors
What are the chemical subtype of nociceptors?
What are the thermal subtypes of nociceptors?
What receptor type is found in thermal nociceptors?
What are polymodal subtypes of nociceptors?
What does Capsaicin activate?
-Polymodal nociceptors TRPV1
What is the transmitter for Capsaicin?
What is the positive feedback that causes secondary activation of nociceptor nerves?
-Chemical messengers released from activated nociceptor nerve endings act locally to release messengers that further activate the nociceptors
Action potentials propagate toward the cell body in the ______ and then enters the ______?
-Dorsal root ganglion
What is sensitization?
-Increased sensitivity and response to stimuli in and near the injured area caused by chemical messengers that make the nociceptors more excitable
What is Hyperalgesia?
-Increased perception of pain in response to painful stimuli
What is Allodynia?
-Pain evoked by normally nonpainful stimuli
What are the major candidates for sensitization?
-Substance P from nerve endings
-Prostaglandins from damaged cells
Prostaglandin receptor stimulation results in activation of what?
-Specific Na+ channels
What do you the activation of specific Na+ channels by PG receptor stimulations do?
-Makes the nociceptive nerve endings more excitable
Do we have selective COX-1 inhibitors?
What is COX-1?
-Is constitutive (always present) in many tissues
What does COX-1 do?
-Renal electrolyte homeostasis
-Renal blood flow maintenance
What are COX -1 inhibited by?
What are some adverse effects of classic NSAIDS?
-GI side effects
What does COX-2 do?
-Cardiovascular protection (constitutive)
What is COX-2 inhibited by?
-Selective COX-2 inhibitors (Celebrex)
What stimulated COX-2?
What do NSAIDS inhibit?
-Synthesis of prostaglandins that are involved in sensitizing the nociceptor nerve ending
How are nociceptors in the viscera normally activated?
-Mechanical stimulation such and distention or contractions (visceral pain can be referred to outside areas)
Do you take NSAIDS for visceral or somatic pain?
Which pain pathways are small, myelinated, and fast conducting?
What are A-delta fibers associated with?
-Mechanical and thermal nociceptors
Are A-beta fibers pain associated?
-No they are proprioception fibers
What pain fibers are small, unmyelinated, and slow conducting?
What are C- axons associated with?
What are plexus of nerves in the tooth called?
-Plexus of Raschkow
Which fiber gives you sharp pain?
Which fiber gives you dull diffuse pain?
Nociceptive fibers synapse with "projection" neurons in what area?
What are important pain neurotransmitters in modulation?
T/F Projection neurons send axons across midline
Where do the ascending pathways ascend contralaterally?
Where does the trigeminal nucleus input to?
Where is nociceptive input heavily modulated at?
-=Dorsal horn with both facilitatory and inhibitory influences
What is Central sensitization?
-Dorsal horn projection neurons also become sensitized and hyper-responsive to nociceptive input.
T/F Prostaglandins can sensitize at the nociceptive level and at the spinal cord level (central sensitization)
T/F The dorsal horn is a major site of action for analgesic drugs
What is a second mechanism for the anti-nociceptive action of NSAIDS for central analgesia?
-Inhibits the synthesis of prostaglandins in the dorsal horn that participate in central sensitization
T/F The dorsal horn is a major site of action of opioids
Sometimes strong touch stimulation can inhibit what?
T/F A Beta and A delta fibers never converge together
-They do converge
Visceral afferent nociceptors ________ on the same pain projection neurons as the afferents from the somatic structures in which the pain is perceived?