Flashcards in Pharm- 17 Deck (84)
What is the role of the limbic system in pain?
Responsible for emotion, social behavior, autonomic control, perception of pain, and memory
What happens in the descending pain modulation?
An ↑ or ↓ of the sensation of pain, possibly due to a 2º neural pathway
What is the fxn of N-type Ca channels?
Plays a strong role in controlling the release of neurotransmitters
AP’s generated in primary afferents induce neurotransmitter release at the dorsal horn of the spinal cord
What happens if u block N-tpye voltage gated Ca channels?
Which receptors are between the C-fiber and secondary projection nuerons?
glutamate R's (NMDA and AMPA)
What is the roles of cannabinoid receptors?
These have regulatory roles in the spinal cord and both are G protein-coupled
What is the fxn of CB1 receptors?
expressed in brain, spinal cord, and sensory neurons; mediator of analgesia following a stressor
What is the fxn of CB2 receptors?
largely expressed in nonneural tissue; especially immune cells including microglia. Up-regulated in spinal cord microglia after peripheral nerve injury
Where is substance P at?
What is the fxn of substance P?
to aid in the signaling response to stimuli of particularly high intensity because they require higher frequency and longer-lasting action potential trains than release of glutamate-containing vesicles.
What is the fxn of B-endorphin, enkapalins, and dynorphins (mu, k, and d receptors) in the CNS?
inhibit synaptic transmission to the brain (reducing pain sensed; analgesia) and are released at several CNS sites in response to pain stimuli
What are the effects of opioid receptor stimulation?
reduced presynaptic calcium conductance (↓ Presynaptic Nt release), enhanced postsynaptic potassium conductance (↓ post-synaptic excitability), and reduced adenylyl cyclase activity. Gi crap.
True or False: Norepinephrine, serotonin (5-HT), glycine, and GABA are major inhibitory neurotransmitters in the dorsal horn of the spinal cord
What is the fxn of the NE/5-HT system for pain?
These systems can limit transfer of incoming sensory to the brain and descending information from the brainstem to the dorsal horn
What is the role of the NE receptors in the spinal cord?
it works on a2 receptors --> Gi mediated inhibition of pain excitation
What is the role of 5-HT3 ligand-gated channels in the spinal cord?
excitatory actions of serotonin in the spinal cord
What is the role of 5-HT G protein-coupled receptors in the spinal cord?
mediate the inhibitory actions of 5-HT
How does the GABA R work?
by hyperpolarizing the membrane by opening K+ or Cl- channels and causing an influx of Cl- or an efflux of K+ .
What are the 2 types of different pain perceptions can result from peripheral sensitization?
alldynia (noninjurous pain) and hyperalgesia
What causes the peripheral sensitization?
peripheral stimuli which induce primary afferents to lower their activation THRESHOLDS thereby making them more sensitive/responsive
What are the mediators to peripheral sensitization?
bradykinin, protons, histamine, prostaglandin E2 (EP receptors), and nerve growth factor (NGF; TrkA receptors)
What types of receptors do the mediators to peripheral senstization act on?
G-protein coupled or receptor tyrosine kinase on nociceptors
What is the first-line drug for peripheral sensitization?
What is the mechanism of action of NSAIDs?
inhibits COX → ↓ prostaglandins → ↓ local inflammatory response and peripheral sensitization
celecoxib, rofecoxib, and valdecoxib block which COX?
celecoxib, rofecoxib, and valdecoxib have an increased risk of what?
What happnens in central sensitization?
Hyperalgesia and allodynia can extend beyond the primary area of inflammation and tissue damage resulting in secondary hyperalgesia/allodynia; this depends on changes in sensory processing in the dorsal horn of the spinal cord.
Why does central sensitization occur?
occurs with repetitive high-intensity stimuli; synaptic transmission activates intracellular signal transduction cascades in the dorsal horn neurons that enhance the response to subsequent stimuli.
What are the receptors invovled with central senstiization?
AMPA, NMDA, glutamate, substance P receptor NK1 and the neutrophin receptor TrkB