Excitatory and Inhibitory Neurotransmission: Synaptic Physiology and Integration Flashcards
1
Q
Define EPSP
A
- a depolarising charge in the rmp caused by the actions of excitatory neurotransmission
- multiple EPSPs or very large EPSPs can cause rmp to cross threshold and result in an AP
2
Q
Define IPSP
A
- negative change in rmp caused by release of an inhibitory neurotransmitter
- inhibits crossing of the threshold and inhibits AP
3
Q
Define graded potential
A
- a change in the rmp caused by an EPSP or IPSP
- such change is caused by neurotransmitter release and is not of a magnitude large enough to cross threshold and result in an AP
4
Q
What determines the strength of the graded potential
A
- how much charge enters the cell
- diminishes over distance due to current leak and cytoplasmic resistance
- amplitude increases as more sodium enters
5
Q
Define the overshoot (OS)
A
reflects the equilibrium potential of the ion that carries the bulk of the inward depolarising current
6
Q
What is glutamate
A
- major excitatory neurotransmitter
- acts on ionotropic receptors to allow Na and Ca in and K out of the cell
- net result is an EPSP, depolarisation and excitation
7
Q
What is GABA
A
- major inhibitory neurotransmitter
- acts on ionotropic receptors to allow Cl into the cell, net result is an IPSP, hyperpolarisation, and inhibition
8
Q
What is an interneurone
A
- locally-acting neurone
- typically releases GABA and so brings about an IPSP and inhibition
- function is local processing of information
9
Q
What is a projection neuron
A
a neuron responsible for conveying signals to other parts of the brain, typically releases Glutamate and so brings about an EPSP
10
Q
What is an excitatory neuron
A
releases a depolarising neurotransmitter (e.g. glutamate)
11
Q
What is an inhibitory neuron
A
releases a hyperpolarising neurotransmitter (e.g. GABA)
