Neurotransmitters Flashcards
What are the 4 conditions to be a neurotransmitter?
- The substance must be synthesized in the presynaptic neuron.
- The substance must be present in presynaptic terminals and have an effect on its postsynaptic target.
- When experimentally applied, the substance must mimic the effects of the substance that is naturally released by the neuron.
- A mechanism must exist for the substance to be cleared from the synaptic cleft.
What are the 3 categories of neurotransmitters?
- Small-molecule
- Large molecule
- Lipid
What are the amines?
Sub-category of small-molecule neurotransmitters, contain
- Acetylcholine
- Biogenic amines
What are amino-acid neurotransmitters?
Sub-category of small-molecule neurotransmitters, contain
- Glutamate
- Glycine
- Gamma-aminobutyric acid (GABA)
What are large-molecule neurotransmitters?
Neuroactive peptides (opioid peptides)
What are the lipid neurotransmitters?
Endocannabinoids
What are the 2 types of endocannabinoids?
Anandamide and 2-arachidonoylglycerol
What are the cannabinoids receptors?
CB1 and CB2
What are the 2 receptors of acetylcholine?
Nicotinic and Muscarinic
What are the 2 main pathways of dopamine?
Nigrostriatal pathway
Mesocorticolimbic pathway
What are the receptors of norepinephrine?
Adrenergic receptors:
Alpha 1
Alpha 2
Beta
What are the 3 receptors of glutamate?
AMPA receptor
NMDA receptor
Kainate receptor
Why is neocortex called like that?
Bc its the latest part of the cortex to develop
Which type of neurotransmitters are most abundant in the brain?
Amino-acid neurotransmitters
Which is the most abundant inhibitory neurotransmitter in the CNS?
GABA
What is the antagonist of glycine? What does it do?
Strychnine
What are biogenic amines?
- Serotonin
2. Catecholamines
What are the catecholamines?
- Dopamine
- Norepinephrine (noreadrenaline)
- Epinephrine (adrenaline)
How is acetylcholine also called?
Cholinergic neurotransmitter
What are the 2 pathways of acetylcholine?
Medial-septal
Pontomesencephalo-tegmental
What are the 3 kinds of opioid peptides?
B-Endorphin
Enkephalin
Dynorphin
What are the 3 opiod receptors?
Mu
Delta
Kappa
Small molecule neurotransmitters are contained in what?
Synaptic vesicles
Large-molecule neurotransmitters are contained in what?
Secretory granules
What are the 2 main types of neurotransmitters, and what do they do?
Excitatory: triggers action potentials
Inhibitory: decreases the likelihood of action potentials
What structures does the medial-septal pathway of acetylcholine uses?
The medial septal nuclei (to cortex and hippocampus) and the basal nucleus of meynert
This pathway goes to cortex and hippocampus
What structures does the pontomesencephalo-tegmental pathway of acetylcholine uses?
The pontomesencephalo-tegmental complex
This pathway goes to the thalamus
Where are nicotinic receptors located?
at the neuromuscular junction; causes your muscles to contract
Where are the muscarinic receptors located?
at the heart; causing it to slow down
Name the antagonist of nicotinic receptors?
Curare
Name the antagonist of muscarinic receptors
Atropine
Where does the nigrostriatal pathway of dopamine originates from? Where is it going? What does it do?
Originates form substantia nigra
Goes to striatum
Goal: regulating voluntary movement and learning motor skills
What are the subdivisions of the mesocorticolimbic pathway of dopamine?
Mesocortical pathway
Mesolimbic pathway
What is the destination of the mesocortical pathway of dopamine and what is its effect?
Direction: from ventral-tegmental area to prefrontal cortex
Goal: Executive functions and selection of appropriate actions
What is the direction and the goal of the mesolimbic pathway of dopamine?
direction: from VTA to nucleus accumbens, amygdala, hippocampus
Goal: control of emotional states and motivation
What are the 5 dopamine receptors and their subclasses?
D1 to D5
Class 1: D1-like (includes D1 and D5)
Class 2: D2-like (includes D2-D4)
Where is norepinephrine produced?
In the locus coeruleus (in the brain stem)
Name 2 important functions of norepinephrine
Role in wakefulness
Activates sympathetic nervous system
How are called norepinephrine receptors?
Adrenergic receptors (or noradrenergic)
What are the categories of adrenergic receptors?
Alpha1, Alpha 2, beta
What are the 2 most common receptors in the brain?
alpha 1 and alpha 2
Where are setotonergic neurons (serotonin)
In the raphe nuclei
Where are the neurons of the serotonergic caudal group?
In the cerebellum and spinal cord
Where are the neurons of the serotonergic rostral group?
In the basal ganglia, thalamus, neocortex, hypothalamus and temporal lobe
What are the main functions of serotonin?
Regulation of mood, sleep and apetite
Also plays a role in the brain’s reward system
What can serotonergic dysfunctions lead to?
depression, skizophrenia, and anxiety-related diseases (like OCD)
What are the 2 receptors for serotonin?
5-HT1 to 5-HT7
What is glutamate synthesized from?
From the amino acid glutamine
What is GABA synthesized from?
Glutamate
What is the most abundant excitatory neurotransmitter in the brain?
Glutamate
What is one main role of glutamate
Formation of long term memories
Which neurotransmitter has a mesocorticolimbic pathway that parallels that of dopamine
glutamate and GABA
What is the main role of GABA? How does it do that?
To silence the activity of neurons, and play a role in the regulation of fear and anxiety
To do that, it allows the entry of cl- to HYPERPOLARIZE the neurons, making them less likely to fire
What is allosteric modulation?
When different chemicals can regulate the activity of a channel by each having their own receptor site on that same channel
What is the major inhibitory neurotransmitter in the brainstem and spinal cord?
Glycine
What is the main role of glycine?
Paralyzing the body during REM sleep
Name a few of the functions of opioid peptides
Pain analgesia, reward mediation, modulation of emotions and response to stress
Which opioid peptide does mu binds with?
B-endorphin (drug-rewarding effects)
Which opioid peptide does delta binds with?
Enkephalin (drug rewarding effects)
Which opioid peptide does kappa binds with?
Dynorphin (regulates mood/stress)
Name the major functions of endocannabinoids
Learning and memory, appetite, sleep, regulation of emotional states
Also modulates the content of dreams
Dysfunction in endocannabinoids can do what?
Cause disorders such as anxiety, depression, and schizophrenia
What is retrograde signaling?
The proces by which the activity of a neuron is regulated by chemical messenger released by its postsynaptic target neuron
