Neurotransmitters Flashcards
What are the 5 rules for being a classical chemical neurotransmitter
1- chemical must be made and stored in presynaptic cells
2- the chemical must be released from presynaptic terminals on action potential
3- released chemical must bind to receptors and cause a biological effect
4- there must be a mechanism to inactivate or metabolise the chemical
5- the chemical should have the same effect if artificially applied to synapse
What is the process for neurotransmitter release
1- action potential
2- vesicle docks
3- neurotransmitter release (exocytosis)
4- neurotransmitter binds to receptor
5- unbound nt transported into presynaptic terminal for reuptake (endocytosis)
6- nt gets broken down or repackaged in vesicles
Where do neurotransmitters come from?
Peptides
- precursor peptide synthesised in rough er
- cleaved in Golgi apparatus to active neurotransmitter
- secretory vesicles bud off from Golgi apparatus
- secretory granules transported to terminal and stored
Monoamines, amino acids and acetylcholine
- precursor molecule synthesised to neurotransmitter
- transported to synaptic vesicle and stored
What is the main difference between peptides, monoamimes and amino acids or acetylcholine neurotransmitters
Peptides neurotransmitters are made in the soma and transported in secretory granules to the terminal
Monoamimes, amino acids and acetylcholine are made from precursor molecules in the terminal and are transported in synaptic vesicles
What is glutamate
Major excitatory NT
Learning and memory
Neuroplasticity
Excitotoxicity- where glutamate kills cells
What is GABA
Major inhibitory NT
modulator of major processes
What are the common amino acids
Glutamate and GABA, glycine and aspartate
Where is glutamate found
Thalamus- cortex and striatum and mid brain
Cell bodies in thalamus and terminals in striatum
Where is GABA found
Interneurons Cerebellum Cortex Striatum Midbrain
How many percent of inhibitory information in the brain is mediated by GABA?
5o%
What are interneurons
Small neurons that are retained in the one brain area
How are amino acids synthesised?
From glucose
Glucose makes glutamate which makes GABA
Glutamate makes GABA through enzyme called glutamatic acid decarboxylase (gad)
How do amino acids metabolise
Released into pre synaptic terminal
GABA is broken down by gaba transaminase and glutamate is recycled
What is acetylcholine
Involved in memory and perceptual learning, movement and REM sleep
Where are acetylcholine cell bodies located
Septa hippocampal pathways
Striatal interneurons
How do we metabolise acetylcholine
Broken down by acetylcholine ester are (ache) to choline and acetic acid
Ach metabolism occurs in the synaptic cleft
Choline is then transported into the presynaptic cell for reuse
What is dopamine involved in
STM
Strategy and planning
Reward
Movement
What are the three catecholamines
Dopamine
Noradrenaline
Adrenaline
What is serotonin involved in
Cognition, emotion and reward
What is noradrenaline involved in
Attention
Fight/ flight
Sleep
What are the 2 indolamines
Serotonin
Melatonin
What is the catecholamines pathway
Dopamine makes noradrenaline, noradrenaline makes adrenaline
Where are dopamine and noradrenaline cell bodies located
Nora- mid brain and further back
Dopamine-, substantia niagra, ventral tegmental area
Where are serotonin cell bodies
The dorsal raphe
Caudal raphe
Rostral raphe
What is the metabolism of monoamimes
Monoamimes are deactivated by monoamine oxidase (Mao) or repackaged into vesicles
What are the transporters for dopamine, noradrenaline and serotonin?
D= dat S= sert N= net
