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Phenotypes associated with this allele
Allele Symbol
Allele Name
Allele ID
Gabbr1tm1Bet
targeted mutation 1, Bernhard Bettler
MGI:2159352
Summary 2 genotypes
Jump to Allelic Composition Genetic Background Genotype ID
hm1
Gabbr1tm1Bet/Gabbr1tm1Bet BALB/c-Gabbr1tm1Bet MGI:3612993
ht2
Gabbr1tm1Bet/Gabbr1+ BALB/c-Gabbr1tm1Bet MGI:3612994


Genotype
MGI:3612993
hm1
Allelic
Composition
Gabbr1tm1Bet/Gabbr1tm1Bet
Genetic
Background
BALB/c-Gabbr1tm1Bet
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Gabbr1tm1Bet mutation (0 available); any Gabbr1 mutation (57 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
nervous system
• audiogenic stimuli induce tonic-clonic seizures in most mice
• several spontaneous clonic seizures lasting from several seconds up to a minute occur each day
• almost all seizures are clonic seizures
• spontaneous tonic-clonic seizures are seen sporadically and these seizures can be induced by audiogenic stimuli
• occasional absence-type seizures occur that include phases of 3-5 Hz spike and wave discharges
• at 3 months of age, mutant sciatic nerves show an increased number of small diameter axons relative to wild-type sciatic nerves
• in mutant sciatic nerves, a higher percentage of axons display a reduction in diameter (<1um) relative to wild-type sciatic nerves which display more axons with a diameter of >2um
• in addition, mutant sciatic nerves show a higher percentage of irregular fiber profiles relative to wild-type sciatic nerves (index of circularity, IC<0.75)
• at 3 months of age, the sciatic nerves of male homozygotes display a significant reduction in myelin thickness relative to wild-type controls
• at 3 months of age, peripheral nervous system (sciatic) nerves of male homozygotes show apparently smaller fibers with thinner myelin sheaths relative to wild-type controls
• reduction in fiber area is likely due to overall decrease in myelin thickness rather than to a reduction in axon area
• at 3 months of age, mutant lumbar DRG display a higher percentage of small to medium neurons (<15,000 um3) relative to wild-type DRG
• neuronal soma is generally smaller in mutant mice and the percentage of large DRG neurons is decreased relative to wild-type controls
• at 3 months of age, male homozygotes display reduced myelin thickness and an increased number of fibers with small axons as well as irregular fiber profiles associated with an decrease in the number of neurofilament 200 kDa-positive fibers in their sciatic nerves
• at 3 months of age, male homozygotes display significant increases in the expression of mRNA and protein levels of the myelin proteins PMP22 and P0 in their peripheral nervous system relative to wild-type and heterozygous littermates
• baclofen has no effect on holding current or input resistance in CA1 pyramidal cells unlike in wild-type cells where it induces an outward current
• baclofen does not evoke depression of excitatory postsynaptic currents unlike in wild-type mice; however the response to adenosine is normal
• baclofen does not inhibit inhibitory postsynaptic currents unlike in wild-type mice; however the response to adenosine is normal
• no notable LTP in a paired protocol of CA3 to CA1 synapses

behavior/neurological
• baclofen does not impair motor coordination unlike in wild-type mice (J:70558)
• neither chlordiazepoxide nor diazepam (classical benzodiazepine anxiolytics) decrease anxiety-like behaviour in the light-dark box test, unlike in wild-type mice (J:101866)
• no difference in latency to enter the dark chamber is seen during training but latencies are decreased in retention tests
• in a forced swim test homozygotes spend less time immobile suggesting decreased depression-related behavior
• in contrast with wild-type mice, administration of classical benzodiazepine anxiolytics i.e. chlordiazepoxide (10 mg/kg, p.o.) or diazepam (7.5 mg/kg, p.o.) prior to testing in the light-dark box, fails to reduce anxiety-like behavior in mutant mice (J:101866)
• a decrease in transitions between the light and dark compartments is seen with significantly less time spent in the light compartment (J:103534)
• reduced paw withdrawal thresholds to mechanical pressure
• at 3 months of age, male mutants do not develop mechanical allodynia in the Von Frey filament test and require a higher stimulus strength to induce a withdrawal response than wild-type mice
• this in contrast with the hyperalgesia observed in the paw pressure test, suggesting that mutants display a differential sensitivity towards mechanical pain tests
• sporadic episodes of intensive running
• in a 2 hour observation period mice more faster and cover longer distances compared to wild-type mice
• at 3 months of age, footprint analysis indicates that toe-spread 2-4 and foot step length are increased by ~24% and ~27%, respectively, in mutant males relative to wild-type controls
• pronounced hyperalgesia to noxious heat is seen in the hot-plate and tail-flick tests (J:70558)
• at 3 months of age, mutant males display a significant reduction in thermal withdrawal latency in the plantar acute pain test relative to wild-type males (J:132683)
• audiogenic stimuli induce tonic-clonic seizures in most mice
• several spontaneous clonic seizures lasting from several seconds up to a minute occur each day
• almost all seizures are clonic seizures
• spontaneous tonic-clonic seizures are seen sporadically and these seizures can be induced by audiogenic stimuli
• occasional absence-type seizures occur that include phases of 3-5 Hz spike and wave discharges

homeostasis/metabolism
• at 9 days post-castration, the LH rise is significantly advanced in female mutants relative to wild-type females, with no significant differences between male genotypes
• however, no differences in the post-castration rise in FSH are noted between wild-type and mutant mice of either sex
• significantly increased basal serum PRL levels in adult male (but not female) mutant mice relative to age-matched wild-type controls
• however, no significant differences in basal luteinizing hormone (LH), follicle-stimulating hormone (FSH), thyroid-stimulating hormone (TSH), and growth hormone (GH) levels between adult wild-type and mutant mice in either sex
• similar percent increase in PRL levels above basal levels between wild-type and mutant males in response to immobilization stress
• baclofen does not alter excitatory or inhibitory postsynaptic currents or holding currents in CA1 pyramidal cells unlike in wild-type mice
• baclofen does not induce hypothermia unlike in wild-type mice

reproductive system
• estrous cyclicity is disrupted with significantly extended periods in estrus and shortened periods in proestrus relative to wild-type females
• however, no significant differences between adult wild-type and mutant females in terms of puberty onset, ovarian weight or estradiol, progesterone and testosterone levels are observed
• a significantly reduced proportion of mutant females (37.5%) get pregnant during the first 30 days of mating relative to wild-type females (87.5%), with no significant differences in litter size between genotypes
• mutant females show normal mating behavior once they get into proestrus; however, only 14% of vaginal plug positive mutant females mated on proestrus show successful pregnancies relative to 75% in control females

growth/size/body
N
• no significant differences in body weight from birth to adulthood in either sex relative to wild-type controls

integument
• reduced paw withdrawal thresholds to mechanical pressure
• at 3 months of age, male mutants do not develop mechanical allodynia in the Von Frey filament test and require a higher stimulus strength to induce a withdrawal response than wild-type mice
• this in contrast with the hyperalgesia observed in the paw pressure test, suggesting that mutants display a differential sensitivity towards mechanical pain tests
• pronounced hyperalgesia to noxious heat is seen in the hot-plate and tail-flick tests (J:70558)
• at 3 months of age, mutant males display a significant reduction in thermal withdrawal latency in the plantar acute pain test relative to wild-type males (J:132683)




Genotype
MGI:3612994
ht2
Allelic
Composition
Gabbr1tm1Bet/Gabbr1+
Genetic
Background
BALB/c-Gabbr1tm1Bet
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Gabbr1tm1Bet mutation (0 available); any Gabbr1 mutation (57 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
behavior/neurological
• phenotype is stated to be similar to that of homozygotes; however no data is presented
• no difference in latency to enter the dark chamber is seen during training but latencies are decreased in retention tests compared to wild-type mice but are increased compared to homozygotes





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last database update
11/26/2019
MGI 6.14
The Jackson Laboratory