10/02 Flashcards
The European book with NDMA Dr. Smidt was reading was right about everything except:
the nomenclature of NMDA
Why don’t arteries compress in the brain when ICP increases?
Because the arteries have a high Internal pressure.
What is the internal blood pressure of arteries in the skull?
100mmHg
Are the second ascending neurons after a nociceptor myelinated?
most of the time, but not always
Which neuron has a difference in myelination in the fast/slow pain pathways?
the first order nociceptor
Where does inhibition happen in the lateral inhibition pathway?
some happens in the dorsal horn, some happens out in the periphery
Where are metabotropic receptors found compared to the 3 inotropic ones we talked about in A&P
the brain
enkephalins are similar to what?
endorphins
enkephalin is the body’s endogenous
opiate system
what kind of receptor is an enkephalin receptor?
GPCR
Where are enkephalin receptors found on our drawing?
on the presynaptic and postsynaptic neurons
Enkephalin receptors are functionally linked to what type of channel?
Potassium
When opiates hitting enkephalin receptors, what should happen?
potassium channels should open, giving potassium more places to leave the cell. This makes the cell more negative and therefore makes the neuron harder to excite
When someone asks you how opiate receptors work, you would tell them that they
increase cell wall permeability to potassium and that inhibits the cells.
What receptor, besides enkephalin receptors, does the first and second order neuron have on them?
alpha 2 receptors
what do alpha 2 receptors do on the 1st and 2nd order neuron in the spinal cord?
open potassium channels
what type of receptor is an alpha 2 receptor?
GPCR
alpha 2 receptor activation at the synapse is going to do what?
shut down the first order nociceptor and the second order in transmission neuron
What are examples of alpha 2 receptor agonist? A&P
xylazine
clonidine
precedex
xylazine activates which receptors?
alpha 1 and 2
List the alpha 2 receptor agonist from most specific to least specific
precedex
clonidine
xylazine
Precedex, clonidine, and xylazine are all drugs that decrease pain by relaxing the CNS, but differ from opiates in that they
don’t produce the same sensations in the top parts of the brain like euphoria.
alpha 2 receptor agonists do what in the CNS?
slow it down
what CNS depressor do people abuse (A&P)
xylazine
what does the media call a horse tranquilizer?
xylazine
xylazine is basically a
tranquilizer
other things that can affect the synapse would include general effects produced by
volatile anesthetics
all the volatile anesthetic drugs that use a gas typically suppress activity throughout the
CNS
How do volatile anesthetics impact the synapse between the first and second order pain neurons?
by increasing potassium conductance
What is the mechanism of action for volatile anesthetic drugs?
opening potassium channels throughout the CNS
What is another thing that volatile anesthetics do besides open K channels that Dr. Smidt mentioned?
they can interact with inhibitory neurotransmitters
Potassium always ______ the cell despite what the internet says
leaves
Where is cox 2 typically expressed?
in our first and second order ascending pain neurons
what induces cox 2 activity?
activity at the synapse
the more pain we have the _____ Cox 2 is expressed
more
what does cox 2 produce?
prostaglandins
What do prostaglandins interact with in the 1st and 2nd order neuron synapse?
receptors located on both the first and second order ascending pain transmission neurons
What do prostaglandins do to the 1st and 2nd order neurons in the ascending pain transmission pathway?
increases their sensitivity to pain by increasing the likelihood of an action potential firing or the likelihood of having multiple action potentials in succession
What is an odd enzyme that can ramp up pain signals?
One of the forms of nitric oxide synthase, iNOS
What is iNOS?
an inducible form of nitric oxide synthase
Why is iNOS’s role in amping up pain odd?
typically you think of nitric oxide synthase as a good thing. It relaxes the blood vessels, keeps our blood pressure down, and gives us organ perfusion when we need it.
what electrolyte supplement can help with chronic pain?
magnesium
what is a downside to magnesium?
you’re your going to be in the bathroom for hours
Why don’t people take calcium supplements to help with chronic pain?
because although it is typically a suppressing agent, it doesn’t help that much with pain
Where is the 3rd order neuron located on the DIC pathway?
a portion of it is in the dorsal horn and a portion is outside of the horn
are fast pain neurons myelinated in the dorsal horn?
yes! there just isn’t enough to make the dorsal horn white
what are the spinal reflex pathways?
stretch
tendon
withdrawal
crossed extensor
which reflexes are pain reflexes?
withdrawal
crossed extensor
which reflexes are stretch or tension reflexes?
stretch
tendon
What are the components of the general spinal wiring schematic for reflexes?
Sensory portion (afferent)
a way to talk to the motor portion
motor portion (efferent)