Lecture 4: Modulation of Membrane Potential - Inhibition Flashcards
What do fast inhibitory neurons enable? What is this important for?
enable an excitatory input to stop the activity of another pathway
this is important in the coordination of antagonistic muscle groups and for selective activation of specific behavioural pathways
Which subunits is the GABAa receptor in the brain composed of?
2 ɑ subunits, 2 β subunits and 1 ɣ subunit
What are GABAa and glycine receptors also known as?
chloride channels
What type of receptors are GABAa and GABAc?
chloride channel ionotropics
What type of receptor is GABAb?
metabotropic receptor
What is the precursor for GABA?
glutamate - converted via Glutamic decarboxylase and co-enzyme pyridoxal phosphate
Which receptors do most post-synaptic neurons have?
glutamate and GABA receptors
What is glycine derived from?
serine - via serine transhydroxy-methylase
What does receptor structure enable?
differentiation between very similar molecules (GABA and glutamate are very similar)
What are the major inhibitory transmitters of the mammalian CNS?
GABA and glycine
What determines the movement of an ion through an ion channel and the direction of that movement?
the concentrations of the ion inside and outside of the cell
What is the chloride concentration in a mature neuron?
remains low in the cell
What is the role of chloride ion channels?
retain the membrane potential approximately at RMP and shunt excitatory inputs
What do Nernst potentials describe?
the point of equilibrium for movement of a given ion through an open channel
What is the equilibrium potential also known as?
the reversal potential
