3. Synaptic Transmission Flashcards
What is the [Na+] in the ECF and ICF?
ECF: 145
ICF: 15
What is the [K+] in the ECF and ICF?
ECF: 4.5
ICF: 120
What is the [Cl-] in the ECF and ICF?
ECF: 116
ICF: 20
What is the [Ca++] in the ECF and ICF?
ECF: 2
ICF: 20-100
What is the resting membrane potential in a neuron?
-70mV
What is the nerst equation?
Used to find the equilibrium potential for 1 ion
E= 61x log(conc outside/conc inside)
What events lead to NT release?
AP is reached and depolarises the axon terminal
Activates voltage gated Ca++ channels
Ca++ influx causes NT release due to activation of Ca++ sensitive fusion proteins
Where is a tripartite synapse common?
Brain
What happens at a tripartite synapse?
Astrocytes are in close contact with synapses
What are the functions of astrocytes
Recycle NTs using glutamine synthetase
Secrete neuro and gliotransmitters (glutamate, D-serine, TNF-a)
Buffer extracellular K+
What are the 2 types of NT receptors?
GPCRs
Ionotropic
Which NTs are excitatory?
Glutamate
ACh
NA
Dopamine
What receptors does glutamate act on?
AMPA, NMDA, kainate
Which NTs are inhibitory?
GABA
Glycine
Serotonin
Dopamine
Which receptors does GABA act on?
GABAA
GABAB
What is co-transmission?
Vesicles with small NTs are often released with larger peptide NTs
What is the function of co-transmission?
Fast response via small NT
Slower, neuromodulatory response via peptide
Name 3 peptide NTs
Neuropeptide Y
Substance P
VIP
What is the action potential threshold for a neuron?
-55mV
What is temporal summation?
More than one neuron releases at the same time
What is spatial summation?
One neuron releases several times
