Lecture 8 - Inhibitory synaptic function

Question 1

give an example of how the coordination of activity for where inhibition is important

Answer 1

knee jerk reflex - antagonist muscle groups

Question 2

give 5 examples of ionotropic receptors which directly gate ion channels (fast)

Answer 2

AMPA/NMDA
nicotinic ach
GABA A
GABA C
glycine

Question 3

give 3 examples of metabotropic receptors (use 2nd messengers and are slow)

Answer 3

metabotropic glutamate
muscarinic ach
GABA B

Question 4

GABA A, GABA C and glycine all have how many subunits?

Answer 4

5

Question 5

p (Rho) 1-3 subunits are specific for which ionotropic receptor?

Answer 5

GABA C

Question 6

at which 2 subunits does GABA bind to on GABA A?

Answer 6

alpha/beta

Question 7

benzodiazepenes bind to GABA A on which 2 subunits?

Answer 7

alpha/ gamma 2

Question 8

do barbituates increase or decrease the affinity of GABA?

Answer 8

increase

Question 9

does alcohol enhance GABA action?

Answer 9

yes

Question 10

do neurosteroids have a positive or negative allosteric modulation to GABA A?

Answer 10

both

Question 11

what kind of pore is located at the centre of a GABA A receptor? which ion is it specific to?

Answer 11

chlorine

Question 12

name the 5 subunits of GABA A

Answer 12

2 x alpha 1
2 x beta 2
gamma 2

Question 13

GABA B is a heterodimer of which 2 things?

Answer 13

GABA B1, GABA B2

Question 14

where do agonists bind to on GABA B- which part of the heterodimer?

Answer 14

B1

Question 15

G protein activation of GABA B is done through which half of the heterodimer?

Answer 15

B2

Question 16

name 2 methods of presynaptic inhibition, preventing release of synaptic inputs into the cell

Answer 16

depolarisation suppression of inhibition (DSI) and endocannabinoid action

Question 17

endocannabinoids go back and inhibit on the …..synaptic neuron

Answer 17

presynaptic

Question 18

the strength of inhibition depends on the intracellular concentration of which ion?

Answer 18

chlorine

Question 19

in epilepsy, GABA becomes problematic and excitatory due to an increase in the level of intracellular ……

Answer 19

chlorine

Question 20

name the 3 ways in which inhibition can be reduced

Answer 20

reduced release of GABA, a shift in E Cl arising from a rise in intracellular [Cl-] and receptor desensitization

Question 21

which type of cells innervate pyramidal cells?

Answer 21

chandelier cells

Question 22

terminals with which type of receptor are wrapped around the axon initial segment of chandelier cells (makes the soma and axon hillock 100% inhibitory)

Answer 22

GABA

Question 23

which type of cells are involved in the synchronization of activity and are useful for memory?

Answer 23

basket cells

Question 24

the regulation of which ion is a major determinant of GABAA function?

Answer 24

chloride