Term
| Is the endogenous pathway ascending or descending? |
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Definition
| Descending. The ascending pathway carried painful impulses to the thalamus |
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Term
| What are endogenous opioids? |
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Definition
Located in the CNS:
- Enkephalins: peripheral and CNS, acts on mu receptors and delta receptor
- Endorphins - releases from anterior pituitary to act on mu and delta receptors
- Dynorphins - Released from posterior pituitary w/ vasopressin to act on the kappa receptor. |
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Term
What are opioid receptor subtypes and their affinities?
Where do the opioids work? |
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Definition
- mu - Endorphins > enkephalins
- Delta - enkephalins > endorphins
- kappa - dynorphins >> either
- work in the peripheral terminals, spinal cord, and brain stem/cortex. |
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Term
| Are there opioid receptors in a joint? |
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Definition
| Yes. If morphine is injected into the joint, works better than IV |
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Term
| How do endogenous opioids work in the spinal cord? |
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Definition
Inhibit vesicle release from the 1st order neuron and/or hyperpolarize 2nd order neurons
How? Block calcium entry and increase K efflux - reduce mediators and decrease impulse.
Inhibition of adenylyl cyclase --> decr cAMP and calcium |
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Term
| How do endogenous opioids affect GABA? |
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Definition
| Opioids inhibit the release of GABA, allowing inhibitory signals to proceed |
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Term
| What is the gate control theory of pain? |
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Definition
| Pain inhibits Enkephalin (a gate), which allows signal to proceed. Rubbing, a TENS, acupuncture allows enkephalin to work again |
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