Flashcards in Study Guide 4 Deck (29)
What is the effect of excitatory NT binding at the membrane?
- brings closer to depolarization
- AP will occur if threshold is reached
What is the effect of inhibitory NT binding at the membrane?
- brings closer to hyperpolarization
- prevents an AP from occurring
When does a neuron fire an action potential?
- when threshold is exceeded
- excitatory NTs » depolarization
How do agonists impact the channels involved in neurotransmission?
- binds to a receptor and activates it to produce a biological response
- agonist causes action (same action as NT)
How do antagonists impact the channels involved in neurotransmission?
blocks the action of the agonist (blocks NT action)
What does an inverse agonist do?
Causes an action opposite to that of the agonist
How can NTs be removed from the synapse?
- can bind to receptor
- degrade in the synapse (ACh)
- taken up by astrocytes (glutamate)
How is an electrical synapse different from a chemical one?
- presynaptic target
- faster transmission
- smaller synapse
Electrical synapse: communication between axons
How is a chemical synapse different from an electrical one?
- postsynaptic target
- slower transmission
- larger synapse
Which type of synapse do NTs use?
Which are more common: chemical or electrical synapses?
What are the macroglia? (Specific cells)
- Schwann cells
What do macroglia do?
Support and maintain neuronal plasticity
What are the microglia?
Immune cells of the brain
What does activation of microglia produce?
Produces inflammatory cytokines within the CNS
How might aging impact microglia?
- may provide brain environment in which microglia activation continues
- contributes to pathogenesis of neuro dz
What makes up the blood brain barrier?
- tight junctions
- surrounded by astrocytes
How is the BBB different from other capillaries? (Structure)
- regular capillaries have pores
- no astrocytes
What do the tight junctions/astrocytes of the BBB means for membrane transport?
require carrier mediated transport across the membrane
To get across the BBB, a substance must be:
- fat soluble (lipophilic)
- hydrophobic (non-polar)
What can compromise the BBB?
What are some strategies to deliver drugs to the CNS when those drugs are not lipophilic?
- Trojan horse
Which drug helps hydrophilic drugs cross the BBB?
What happens with hyperosmosis?
- endothelial cells lose H2O and shrink
- space that is left can be used for drug delivery
What is microcatheterization?
- small amount of mannitol is delivered to a specific place
- can be used to deliver anti-clotting drugs as well
How do microbubbles work for drug delivery?
- fizzy saline
- a beam of US makes them vibrate in a space
- causes opening of barrier