Neurotransmitters Flashcards
1
Q
What are neurotransmitters?
A
- Signaling molecules released in the brain to regulate neural activity
2
Q
What are hormones?
A
- Signaling molecules released into the blood
3
Q
What are the different types of neurotransmitters?
A
- Classical, conventional neurotransmitters
- Neuropeptides
- Lipid-based neurotransmitters
- Gasotransmitters
4
Q
What are the classical neurotransmitters (6)?
A
- glutamate
- GABA
- dopamine
- norepinephrine
- acetylcholine
- serotonin
5
Q
What is glutamate?
A
- main excitatory neurotransmitter
- because all ionotropic glutamate receptors let sodium in, causing EPSCs and depolarization
- Drugs that activate glutamate receptors often cause seizures and excitotoxicity
- Drugs that block glutamate receptors slow you down
6
Q
What is GABA?
A
- Main inhibitory neurotransmitter
- because all ionotropic GABA receptors let chloride in, causing IPSCs and hyperpolarization
- Drugs that activate GABA receptors slow you down
- Drugs that block GABA receptors often cause seizures
7
Q
What are the main neuromodulators?
A
- dopamine
- norepinephrine
- acetylcholine
- serotonin
8
Q
What type of neurotransmitters do more than 99.9% of neurons release?
A
- glutamate and GABA
9
Q
What are neuromodulators?
A
- primarily act on metabotropic receptors and tend to exert a modulatory influence on cell activity (not fast)
- released from small collections of neurons that send their axons out widely
- most of their receptors are g-protein coupled receptors, not ion channels
- they typically don’t produce immediate EPSPs or IPSPs
- they can diffuse short distances outside of the synapse and influence the activity of neighboring neurons
10
Q
What are classical/conventional neurotransmitters?
A
- modified amino acids (small molecules)
-synthesized locally in axon terminals - packaged in small synaptic vesicles that dock close to the site of Ca2+ entry in the axon terminal
- recaptured and reused (via reuptake proteins)
- rarely leave the synapse
- have both ionotropic AND metabotropic receptors (dopamine and norepinephrine are exceptions to this rule)
11
Q
What are neuropeptides?
A
- a small chain of amino acids (basically a protein that is only 10-30 amino acids long)
- synthesized in the cell body, then transported down the axon and released just once
- packaged in large dense core vesicles that dock a ways back from the site of Ca2+ entry in the axon terminal
- not recycled
- may diffuse long distances and exert action at a distance
- only have metabotropic receptors
12
Q
What are lipid based signalling molecules?
A
- fat soluble molecules (cut from the cell membrane)
- anandamide and arachidonoyl glycerol
- synthesized and released on demand, as needed
- are not packaged in vesicles (they can pass through cell membranes if not attached to something)
- only have metabotropic receptors
- signal backwards (they are released from postsynaptic membrane and the receptors are on axon terminals)
13
Q
What are gasotransmitters?
A
- primarily nitric oxide
14
Q
What happens when a neurotransmitter is made?
A
- it gets packaged into a synaptic vesicle by a vesicular transporter
15
Q
What are the monoamines?
A
- serotonin
- dopamine
- norepinephrine
