Lecture 8 - Inhibitory synaptic function Flashcards
give an example of how the coordination of activity for where inhibition is important
knee jerk reflex - antagonist muscle groups
give 5 examples of ionotropic receptors which directly gate ion channels (fast)
AMPA/NMDA
nicotinic ach
GABA A
GABA C
glycine
give 3 examples of metabotropic receptors (use 2nd messengers and are slow)
metabotropic glutamate
muscarinic ach
GABA B
GABA A, GABA C and glycine all have how many subunits?
5
p (Rho) 1-3 subunits are specific for which ionotropic receptor?
GABA C
at which 2 subunits does GABA bind to on GABA A?
alpha/beta
benzodiazepenes bind to GABA A on which 2 subunits?
alpha/ gamma 2
do barbituates increase or decrease the affinity of GABA?
increase
does alcohol enhance GABA action?
yes
do neurosteroids have a positive or negative allosteric modulation to GABA A?
both
what kind of pore is located at the centre of a GABA A receptor? which ion is it specific to?
chlorine
name the 5 subunits of GABA A
2 x alpha 1
2 x beta 2
gamma 2
GABA B is a heterodimer of which 2 things?
GABA B1, GABA B2
where do agonists bind to on GABA B- which part of the heterodimer?
B1
G protein activation of GABA B is done through which half of the heterodimer?
B2
name 2 methods of presynaptic inhibition, preventing release of synaptic inputs into the cell
depolarisation suppression of inhibition (DSI) and endocannabinoid action
endocannabinoids go back and inhibit on the …..synaptic neuron
presynaptic
the strength of inhibition depends on the intracellular concentration of which ion?
chlorine
in epilepsy, GABA becomes problematic and excitatory due to an increase in the level of intracellular ……
chlorine
name the 3 ways in which inhibition can be reduced
reduced release of GABA, a shift in E Cl arising from a rise in intracellular [Cl-] and receptor desensitization
which type of cells innervate pyramidal cells?
chandelier cells
terminals with which type of receptor are wrapped around the axon initial segment of chandelier cells (makes the soma and axon hillock 100% inhibitory)
GABA
which type of cells are involved in the synchronization of activity and are useful for memory?
basket cells
the regulation of which ion is a major determinant of GABAA function?
chloride
