Neurotransmitters Flashcards
What are the two main classical neurotransmitters?
- Glutamate
-GABA
What type of information do the main classical neurotransmitters deal with?
sensory information
What is the basic effect of glutamate on brain chemical and electrostatic activity?
- It is an excitatory neurotransmitter
- Fast EPSP
What do all ionotropic glutamate receptors have in common?
let sodium in
What do all ionotropic GABA receptors have in common?
Let in chloride
What is the basic effect of GABA on brain chemical and electrostatic activity?
- inhobitory neurotransmitter
- fast IPSP
What is the main difference between neuromodulators and neurotransmitters?
Neuromodulators cannot affect ionotropic receptors. They only affect metabotropic receptors
What is the difference between the effect of neuromodulators and that of neurotransmitters?
- neuromodulators will tend to alter the postsynaptic activity to modulate it, but they do not generally cause fast EPSPs or IPSPs
what is the action of ionotropic glutamate receptors?
let in sodium ions (EPSP and depolarization)
What are the effects of glutamate agonists?
Seizures
Excitotoxicity
what are the effects of glutamate antagonists?
dissociative anesthetics
What is the action of ionotropic GABA receptors?
- let in chloride ions
- cause IPSP
- hyperpolarization
What are the neuromodulators?
- acetylcholine
- dopamine
- serotonine
- norepinephrine
What type of effects do neuromodulators have?
- subtle effects: not visible EPSPs or IPSPs
Where do the neuromodulators diffuse?
short distances outside of the synapse
Where are the conventional neurotransmitters released?
inside the synapse
Where are neuromodulators produced?
In some specialized neurons
Where are GABA and Glutamate produced?
Pretty much every neuron produces one or the other
Are neuromodulators present only in the brain?
No, they are present as hormones inside the blood
What is the structure of conventional neurotransmitters?
- amino acid derivatives
- single amino acids
What are the conventional neurotransmitters?
- Gaba
- Glutamate
- dopamine
- serotonine
-acetylcholine - norepinephrine
Where are the conventional neurotransmitters synthetized?
in the axon terminal
How are the conventional neurotransmitters secreted?
- through small synaptic vesicles
- the synaptic vesicles will dock very close to the site of Ca entry in the axon terminal
What happens to the classical neurotransmitters after they have their effect?
- recaptured and reused
Where is the effect of classical neurotransmitters?
- binds to receptor directly across the synapse (GABA and Glutamate)
- can go to neighbouring neurons (neuromodulators)
What is the structure of neuropeptides?
Small chain of amino acids (baby sized proteins)
Where are neuropeptides synthetized?
In the soma
Why are neuropeptides necessarily made in the soma?
necessitate DNA transcription and translation
What happens to neuropeptides after they have been secreted?
They are destroyed (only used once)
how are neuropeptides secreted?
secreted from large dense core vesicles
these will be secreted after the vesicles containing conventional neurotransmitters
What type of receptors do the neuropeptides activate?
ONLY metabotropic receptors
Where do the neuropeptides diffuse?
- can diffuse long distance
- non synaptic communication
What is non synaptic communication?
When a neuropeptide diffuses away from the axon terminal that has released it to and then has an effect on a much further neuron
What type of neurotransmitter is associated with non synaptic communication?
Neuropeptide
How are lipid-based signaling molecules synthetized and released?
On demand
That is all we know
How are lipid-based signaling molecules secreted?
In a non vesicular manner
By post-synaptic neurons
What type of receptors are affected by lipid-based signaling molecules?
- metabotropic receptors on the pre-synaptic neuron
Where is the effect of lipid-based signaling molecules?
typically: on pre-synaptic neurons
What is the typical effect of lipid-based signaling molecules?
- hyperpolarize the pre-synaptic neuron
- stops the signal (there is too much signal being sent)
What type of neurotransmitter is cannabinoid?
lipid-based signaling molecule
what are lipid-based signaling molecules made of?
pieces of cell membraine that are clipped off
What happens to lipid-based signaling molecules after they have their effect?
Destroyed
What are the only neurotransmitters that are recycled?
Classical neurotransmitters
What are the only neurotransmitters that can activate ionotropic receptors?
GABA and Glutamate
How are classical neurotransmitters produced and used?
1) free-floating amino acids in axonic terminal
2) an enzyme finds a loose amino acid and turns it into an NT
3) NT floats around
4) NT put into a vesicle
5) influx of calcium ions
6) vesicle fuses with membrane
7) the vesicle releases nerutransmitters into the synaptic cleft
What are monoamine neuromodulators?
The four common neuromodulators
What is the structure of monoamine neuromodulators?
Composed of just one amino acid
they all have a relatively similar structure
What is the protein that packages monoamine neuromodulators in vesicles?
VMAT
What are catecholamines?
- dopamine
- norepinephrine
- epinephrine
Why are the catecholamines classified together, as one family?
They have an extremely similar molecular structure
What are neuropinephrine and epinephrine synthetized from?
Dopamine
What is a dirty drug?
Affects more than one receptor of the monoamies, as they are very similar. Most drugs are dirty drugs. It is extremely hard to synthetize a molecule that will affect only one of the types of neuromodulator receptors.