Transgenic mice and NMDA receptor function

Question 0

what promoter was used in transgenic mice to drive expression the cre transgene?

Answer 0

the promoter of the Grik4 gene because it is highly expressed in the pyramidal cells of the CA3 region of the hippocampus

Question 1

what is highly expressed in the CA3 region of the hippocampus?

Answer 1

Grik4

Question 2

how did the CA3 specific NR1 KO mice perform in the water maze test ?

Answer 2

mice performed normally in the maze and in probe trials

- they has normal spatial reference memory

Question 3

what did the experimenters do the CA3 NR1 KO mice to make to the morris water maze more difficult ?

Answer 3

they made it more challenging by reducing the amount of cues

- this impaired their spatial memory

Question 4

what was the difference between the floxed and the mutant in the water maze when there was partial visual cues?

Answer 4

the mutant spent less time around the platform

Question 5

what is the striatum ?

Answer 5

it is a subcortical part of the forebrain

it is a major input station of the basal ganglia

Question 6

what is the basal ganglia associated with ?

Answer 6

a variety of functions, including motor control and learning

Question 7

how were striatum specific NR1 KO mice produced?

Answer 7

made by restricting the expressio of the RGS9-2 protein - this is a variant of the RGS9 gene whihc is expressed predominantly in the striatum

Question 8

what happened to the KO mice on the rotarod?

Answer 8

rotarod is a spinning rod connected to a computer which records the amount of time the mouse spends on the rod and the speed at which the rod is turning
- the KO mice couldnt stay on the rotating rod

Question 9

what is the rotarod test used to test ?

Answer 9

to assess motor coordination and balance in rodents - after repeated trials motor learning can be tested

Question 10

what experimental damage affects the rotarod test ?

Answer 10

damage to the basal ganglia and cerebellum as well as drugs such as alcohol which affect motor function

Question 11

on the rotrod test what are mice compared on ?

Answer 11

their ability to remain on the rod either by latency to drop off or the final speed achieved by accelerating the rod before they fall off

Question 12

what were the results produced by striatum specific NR1 KO mice on the rotarod test ?

Answer 12

it caused impaired motor learning therefore the striatum is involved in a subset of motor learning
the first 3 trials showed no statistically significant difference between the control mice and the KO mice but between trials 4-6 the control mice demonstrated significant increase in time spent on the rotarod whereas the KO mice didnt

Question 13

where was a dopamine neurone specific NR1 KO produced ?

Answer 13

in the ventral tegmental area

Question 14

how was a dopamine neurone specific NR1 KO produced ?

Answer 14

crossing floxed NR1 mice with dopamine neurone specific cre mice

Question 15

what is the name of the dopamine neurone specific cre mice ?

Answer 15

Slc6a3- cre mice

Question 16

what promoter drove cre recombinase in the Slc6a3 mice ?

Answer 16

driven by endogenous Slc6a3 promoter (dopamine transporter)

Question 17

what is the VTA the origin of ?

Answer 17

origin of the dopaminergic cell bodies of the mesocorticolimbic dopamine system
- widely implicated in the drug and natural reward circuitry f the brain - thought to be involved in drug addiction

Question 18

what techniques can be used to prove that the NR1 was deleted in the DA neurones ?

Answer 18

immunoflurorescence of cre and fluorescent in situ hybridiation of NR1 mRNA

Question 19

what was normal in the dopamine NR1 KO mice ?

Answer 19

normal in size, mobility, food intake, and reproduction

had normal basal locomotor activities using elevated plus maze test

Question 20

what does conditioned place preference measure (CPP)?

Answer 20

measures an animals tendency to stay in a chamber associated with rewards or safety(rather than a non-reward chamber)

Question 21

what was determined in the dopamine neurone specific NR1 KO mice during a nictonine preference test ?

Answer 21

mice tend to prefer dark areas instead of brightly lit areas however they conditioned mice to like the brightly lit area by injecting them with a large dose of nicotine
however the NR1 KO mice didnt confer preference to the brightly lit area by nicotine injection therefore this suggests that the NMDA receptors in the dopamine receptors are critical for the development of nicotine addiction- therefore the NR1 subunit could be a target for nicotine addictions

Question 22

how were dorsal root ganglion specific NR1 KO produced ?

Answer 22

mice with loxP sites flanking exons 11-22 of the NR1 subunit
crossed with
mice which expressessed cre recombinase under the control of the promoter peripherin

Question 23

what is the DRG?

Answer 23

nodule on a dorsal root of the spine that contains cell bodies of neurons that carry signals from sensory organs

Question 24

where were no differences seen between the DRG NR1 KO mice and the control mice ?

Answer 24

no difference in motor coordination and basal nociceptive responses

Question 25

what is the formalin test ?

Answer 25

it involves injecting one of the hind paws of a mouse with 5% formalin and counting the nociceptive behviours (licking, lifting or shaking of injected paw)

Question 26

what are the 2 behavioural phases which occur in the formalin test ?

Answer 26

phase 1- early phase - this occurs during the first 5 mins after injection
phase 2- prolonged response which occurs after a quiescent period after the early phase

Question 27

what happened to phase 2 in the DRG NR1 KO mice and what does this suggest ?

Answer 27

it caused a decreased response in phase 2

suggesting that NR1 expressed in primary afferents plays an important role in the development of sensitized pain states

Question 28

what does the KO of NR1 cause?

Answer 28

causes perinatal lethality

- therefore it is impossible to obtain adult animals for studying the effects of NR1

Question 29

what does cre-loxP recombination permit?

Answer 29

provides a way to KO NR1 in specific tissues within an animal- conditional ko