Lecture 12 - Ketamine

Question 1

Where are NMDA receptors found?

Answer 1

-NMDA receptors are largely found in hippocampus and cortex

Question 2

What drug binds to the PCP binding site in NMDA receptors?

Answer 2

-Ketamine (aka special K or horse tranquilizer)
-it can be an NMDA channel blocker
-it is a restricted drug because of its abuse potential

Question 3

What are the uses of different doses of ketamine?

Answer 3

-high dose –> general anesthetic
-medium dose –> psychedelic/hallucinogenic
-low dose –> treatment resistant depression

Question 4

How effective are antidepressants?

Answer 4

-known antidepressants are effective in 60-70% of the depressed population
-about the same for psychotherapy
-placebo is 50-60% effective

Question 5

What are the effects of [low dose] ketamine for treatment resistant depression?

Answer 5

-single low dose of ketamine can cure depression overnight and last for 3-6 months

Question 6

What does ketamine bind to?

Answer 6

-ketamine also binds to microglia
-microglia are the provisional immune cells of the brain (because of BBB there is no immune system)
-microglia walk around the brain looking for damage, and they eat all the debris from damaged neurons
-ketamine can deactivate microglia cells

Question 7

What is one of the theories of the cause of depression?

Answer 7

-depression is actually an inflamatory response of your nervous system and through certain pathways, through serotonin or norepinephrine, we can sometimes turn down that inflammatory response
-or more immediately go right to the source, the microglia, and shut it down with ketamine

Question 8

What would happen if a schizophrenic individual took ketamine?

Answer 8

-giving ketamine to a patient with schizophrenia would trigger a psychotic episode