CNS 1 Flashcards
Name two ways neurotransmitter action is terminated.
Enzymatic Degradation or Reuptake
What effect does an excitatory nt have?
Activates post-synaptic receptors –> increase in Na+ ( and Ca2+) permeability–>membrane depolarization
What effect does an inhibitory nt have?
Activates post-synaptic receptors –> increase in Cl- permeability–>membrane depolarization.
When will IPSP not occur?
At rest since membrane is already at equilibrium.
How are the amino acids glutamate, GABA, and glycine removed from the presynaptic terminal?
through re-uptake by a transporter
How is acetylcholine removed from the presynaptic terminal?
By Acetylcholinesterase
Only choline is taken back up by a transporter into presynaptic neuron.
Name the transporter that coincides with each nt:
GABA, Dopamine, Serotonin, NE, Glutamate
GABA- GAT Dopamine - DAT Serotonin- SERT NE- NET Glutamate- EAAT
What special cell is used to convert glutamate to glutamine before re-uptake into presynaptic neuron?
Glial cell
Once NE, Serotonin, DA are taken back up in presynaptic cell, what two things can happen?
1) repacked by VMAT2
2) Degraded by MAO
precursor of GABA is what and what vitamin is needed for synthesis?
glutamate, Vit B6
Name the repackaging enzyme that coincides with each nt:
GABA, Dopamine, Serotonin, NE, Glycine
GABA- VGAT DA- VMAT2 Serotonin- VMAT2 NE- VMAT2 Glycine- VIAAT
Where do neurotransmitters bind on direct receptors?
Directly to receptor
Where do neurotransmitters bind on indirect receptors?
Typically bind G-protein that causes opening of ion channel downstream.
What three steps in GPCR signal cascade causes signal amplification?
1) Receptor- Gprotein
2) 2nd Messenger
3) Protein Kinase phosphorylation of target proteins
What type of receptor are Cholinergic Nicotinic receptors?
Direct (Ion Channel)
What type of receptor are Cholinergic Muscarinic receptors?
Indirect (GPCR)
What type of receptor are GABAa receptors?
Direct (Ion Channel)
What type of receptor are GABAb receptors?
Indirect (GPCR)
The biogenic amines DA, NE, and Epi work on what type of receptor?
Indirect (GPCR)
What three places can GABA be taken up into?
Presynaptic neuron, postsynaptic, and glial cells
Name three Ionotropic Glutmate receptors.
NMDAR, KA, GluR
What type of receptor does glycine use?
All Direct (Ion Channels)
What does a protein phosphatase do?
Removes phosphate
Does NOT always inactivate!
What does a protein kinase do?
Adds phosphate
Does NOT always activate!
What is desensitization?
Upon giving a second dose of drug you get reduced response due to desensitization of receptor or uncoupling.
NOT a change in receptor number.
What is coactivation and give an example.
When a nt requires second agonist to bind in order to activate.
Glycine is coactivator for glutaminergic NMDA R.
When does downregulation occur?
After prolonged exposure to agonist. Due to decreased receptor number.
When does upregulation occur?
After prolonged exposure to antagonist. Due to increase in receptor number.
What is potentiation?
Increased response to an agonist by binding to an allosteric site on the receptor.
Where is the origin of Dopamine?
Substantia Nigra
Where is the origin of NE?
Locus Coeruleus
What is the origin of Serotonin?
Raphe nuclei
Main functions of histamine?
Wakefulness, motion
Where are GABAergic neurons?
Widespread, known as interneurons!
Major inhibitory neurotransmitter.
Where do dopaminergic neurons of the substantia nigra project to?
Basal Ganglia
Prefrontal cortex
Limbic system
Origin of glutaminergic neurons?
thalamus
subthalamic nuceli
