Week 1 - Introduction To Systems Flashcards
What is Systems Neuroscience?
Studies the function of neural circuits and systems
It is an umbrella term encompasses many areas of study concerned with how nerve cells behave when connected to form neural networks
What are examples of amino acid neurotransmitters?
GABA
Glutamate
Glycine
What are examples of amine neurotransmitters?
Acetylcholine Dopamine Epinephrine Histamine Norepinephrine Serotonin
What are examples of peptide neurotransmitters?
Cholecystokinin Dynorphin Enkephalins N-Acetylaspartylglutamate Neuropeptide Y Somatostatin Substance P Thyrotropin-releasing hormone Vasoactive intestinal peptide
What are neurotransmitters involved in?
Every neuronal system
E.g. motor system [Parkinson]
Failure/degeneration of dopaminergic neurons
5-HT serotonin
What are the differences between classical neurotransmitters, neuromodulators, neurotrophic factors depend on?
The duration of action of neurotransmitters e.g.
GABA (inhibitory)
Glutamate (excitatory)
ACH
Adrenaline
Fight or flight neurotransmitter
Noradrenaline
Concentration neurotransmitter
Dopamine
Pleasure neurotransmitter
Serotonin
Mood neurotransmitter
GABA
Calming neurotransmitter
Acetylcholine
Learning neurotransmitter
Glutamate
Memory neurotransmitter
Endorphins
Euphoria neurotransmitter
What is Neuromuscular junction?
- Multi-vesicular release
2. Acetylcholine (excitatory)
What is central synapse?
- Single release zones
2. Glutamate (excitatory)
What is inhibitory neurotransmission?
- GABA (in the brain)
2. Glycine (in the spinal cord)
What are ligand-gated?
G protein coupled/metabotropic receptors
What do Metabotropic receptors activate?
Secondary messengers
What is the general structure of ionotropic receptors?
A relatively large multi-subunit compels
Composed of 4-5 individual proteins
Combine to form an ion channel through membrane
What is the mechanism of ionotropic receptors?
In the absence of neurotransmitters, ion channel exists in a closed state (impermeable to ions)
Binding of a neurotransmitter molecule induced rapid conformation change allowing molecules to flow down their electrochemical gradients
The ion flow ceases when the neurotransmitter dissociates from the receptor
Or the receptor becomes desensitised
What is the general structure of metabotropic receptors?
A single polypeptide, although domestic form exists
What is the mechanism of metabotropic receptors?
Exerts it’s effect not directly by opening an ion channel but through binding to and activating GTP-binding proteins
Transmitters that bind to GPCR typically produce what type of response?
Slower onset
Longer duration
What is the cell bodied of the Cholinergic system?
Nucleus of Meynert (projects to the cortex) Medial septum (projects to hippocampus)
What is the nucleus of Meynert and medial septum vital for?
Normal cognition and memory
What do cell bodies in brain system (Cholinergic system) project to?
Diencephalon
Basal Ganglia
What are diencephalon and Basal Ganglia important for?
sleep and arousal
What is the Cholinergic system referred to as?
Learning system
What are the receptors for the Cholinergic system?
Nicotine (nicotinic receptors)
Muscarine (Muscarinic receptors)
What are the cell bodies of Dopaminergic system?
Substantia Nigra
Ventral tegmental area
Midbrain
What do dopamine neurons in the substantia Nigra give rise to?
Nigrostriatal pathway (important for motor control)
What do dopamine neurons in the ventral tegmental area give rise to?
Mesocorticolimbic pathway
Reward, reinforcement and appetitive behaviour
What are the receptors of the Dopaminergic system?
Metabotropic receptors
All are G-coupled receptors
What can dopamine have?
Excitatory or inhibitory effect depending on which receptors it binds to
What does dopamine binding to one of its 5 receptors activate?
G-protein
What is D1-like receptors?
D1 and D5
Stimulate the activity of adenylyl cyclase
What is D2-like receptors?
D2, D3 and D4
Inhibit the activity of adenylyl cyclase
What is the cell bodies of Noradrenaline system?
Locus coeruleus
About 12,000 neurons per hemisphere
What are the projections for Noradrenaline system?
Diffuse to the entire cortical mantle, diencephalon and cerebellum
Each NA neuron can make up to how many synapses?
250,000
What are the receptors for Noradrenaline system?
Metabotropic receptors
What is the function of Noradrenaline system receptors?
Regulate central role in autonomic function
In the periphery, what does adrenaline do?
Increase heart rate
Construct blood vessels
Relaxes airways
What are all the postsynaptic noradrenergic receptors?
Excitatory (B1, B2, B3 and A1)
What is the presynaptic alpha 2 autoreceptor?
Inhibitory
What are the cell bodies for serotonin (5-HT) system?
Midline raphe nuclei throughout the brainstem
Where does the caudal raphe nuclei project to?
Spinal cord
Important for the modulation of afferents pain signals
Where does the raphe nuclei project to?
Everywhere else
What are the receptors for the serotonin system?
5-HT1E-F and 5-HT2A-C (post-synaptic metabotropic receptors)
5-HT1A,B and D (presynaptic Metabotropic receptors)
5-HT3 (postsynaptic ionotropic receptors)
