Flashcards in Neurotransmitters Deck (46):
What is the one class of large neurotransmitters called?
What are the four widely studied amino acid neurotransmitters?
4. Gamma- aminobutyric acid (GABA)
What is the most prevalent excitatory neurotransmitter in the CNS.
What is the most prevalent inhibitory neurotransmitter in the CNS?
What are four types of monoamine transmitters?
Which monoamine transmitters are catecholamines?
Dopamine, epinephrine and norepinephrine
Which monoamine transmitters are indolamines?
What amino acid is dopamine, epinephrine and norepinephrine synthesized from and how?
The are synthesized initially by tyrosine that attaches to an L-dopa making dopamine and the dopamine attaches onto an enzyme that converts dopamine to norepinephrine and then another enzyme attaches to norepinephrine and converts it to epinephrine
How is serotonin synthesized?
By amino acid tryptophan
What are neurons that release norepinephrine called?
What are neurons that release epinephrine called?
How is acetylcholine made?
By adding an acetyl group to a choline molecule
Where is acetylcholine normally released?
- neuromuscular junctions or ANS
What enzyme breaks down acetylcholine in the synapse?
What are neurons that release acetylcholine called?
What are the two classes of unconventional neurotransmitters?
- soluble gas neurotransmitters
What does the soluble gas neurotransmitters include? Why is it difficult to study?
- nitric oxide and carbon monoxide.
- difficult to study because they only exist for a few seconds
What are endocannaboinoids and what are they made of?
- similar to THC found in marijuana
- most commonly studied is called Anandamide which have an effect on presyanptic neurons by inhibiting synaptic transmission
What are the five categories of neuropeptides?
1. Pituitary peptides --> neuropeptides as hormones released by pituitary
2. Hypothalamic peptides --> neuropeptides as hormones released by hypothalamus
3. Brain-gut peptides --> neuropeptides released in the gut
4. Opioid peptides --> neuropeptides similar to structure of active ingredient in opium
5. Miscellaneous peptides --> neuropeptide transmitters that don't fit into any of the 4 mentioned above
What are the two effects that drugs can have on synaptic transmission?
1. They can facilitate the effects of a particular neurotransmitter --> Agonists
2. They can inhibit the effects of a particular neurotransmitter --> antagonists
What are the seven general steps common to neurotransmitter process?
1. Synthesis of NT
2. Storage in vesicles
3. Breakdown of any NT that leaks from vesicles
5. Inhibitory feed back via auto receptors
6. Activation of post synaptic receptors
What effect does an agonistic drug have on synaptic transmission?
1. Increases synthesis of NT
2. Increases number of NT by destroying degrading enzymes
3. Increases release of NT
4. Blocks inhibitory effect of autoreceptors
5. Binds to post synaptic receptors and activates them or increases the effect on them to NTs
6. Blocks deactivation
How does an antagonistic drug effect synaptic transmission?
1. Blocks synthesis of NT
2. Causes NT to leak from vesicles
3. Blocks release of NT from vesicles (stops exocytosis)
4. Activates autoreceptors
5. Acts as a receptor blocker by binding to post synaptic receptors
What are the two neurotransmitters that can bind to acetylcholine receptors?
What are the general properties of nicotine?
- found in tabacco
- formed by nicotinic receptors
- located in PNS and CNS
- near junctions between motor neurons and muscle fibre
- functions ioniotropically
What are the general properties of muscarine?
- poisonous substance found in some mushrooms
- formed by muscarinic receptors
- found in PNS and CNS
- located in the autonomic nervous system
- function metabotropically
What is atropine?
- receptor blocker that has an antagonist effect on acetylcholine release by binding to muscarinic receptors in the ANS
- causes disruptive effects to memory
What is curare?
Curare is an antagonist drug to acetylcholine release by blocking the release of it and instead releasing nicotine
- causes a block in the transmission at neuromuscular junctions therefore, paralyzing recipients and killing them by blocking respiration
What is botox?
- also another nicotinic antagonist
- blocks the release of acetylcholine at neuromuscular junctions
What is the main ingredient in opium?
Where does morphine bind to in the brain and what does it do?
- morphine hangs around the cerebral aqueduct which is the connection between the third and fourth ventricles near the midbrain. this area is called periaqueductal gray (PAG)
- highly addictive
What are endogenous opioids and what are two classes of them?
- endogenous opioids are naturally occurring opioids that have been discovered in our bodies
- the first class is enkephalins
- the second class is endorphins
- they are all neuropeptides (large) and all of their receptors are metabotropic
What conclusion is made between how schizophrenia and parkingson's disease are linked?
- parkingsons results as a breakdown of the pathway of dopamine from the substantia nigra to the striatum (in the basal ganglia system which controls movement) --> therefore a drug that could treat parkingsons has to be agonistic to dopamine
- schizophrenia is said to be caused by too much dopamine in the D2 dopamine receptors. --> therefore, a drug that could treat schizophrenia would be antagonistic to dopamine
What are the four classes of small-molecule neurotransmitters?
the three conventional ones are:
1. Amino acids
The unconventional ones are:
4. Unconventional neurotransmitters
What enzyme is involved with the synthesis of acetyl choline?
What enzyme breaks down acetylcholine?
What enzyme makes GABA?
Glutamic acid decarboxylase makes gaba from glutamic acid
What enzyme makes L-Dopa from tyrosine?
What enzyme makes dopamine from L-dopa?
What enzyme makes norepinephrine from dopamine?
Dopa beta hydroxylase
What enzyme makes epinephrine from norepinephrine?
Phenylethanol -N- amine methyl transferase (PNMT)
What enzyme makes 5-hydroxytryptamine?
What is the role of fluoxetine on the brain?
Inhibits 5-HT reuptake (anti depressent)
What is the effect of busiprone on 5HT.
Stimulates release of receptor subtypes of serotonin
What is dale's principle?
The idea that one neuron has only one neurotransmitter (not true, one neuron has a small molecule NT and a neuropeptide)