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Phenotypes Associated with This Genotype
involves: 129P2/OlaHsd
Find Mice Using the International Mouse Strain Resource (IMSR)
Mouse lines carrying:
Chrnb2tm1Jpc mutation (0 available); any Chrnb2 mutation (4 available)
phenotype observed in females
phenotype observed in males
N normal phenotype
nervous system
• ipsilateral retinogeniculate projections remain widespread in the dorsal lateral geniculate through 12 days of age

• periodic retinal discharges are present as early as 2 days of age in Multi Electrode Recordings
• wave and spike frequencies are greater than controls
• retinal firing frequency is increased
• increased burst frequency
• higher interspike intervals between bursts, lower percent of time cells are firing at greater than 10 Hz
• retinal waves not regulated by nicotinic acetylcholine receptors as is true for controls
• beta-glycerrhetinic acid (gap junction blocker) decreases wave frequency in mutants but not in controls

respiratory system
• breathing parameters are more or less normal at 8 days of age
• tidal volume is increased post hypoxia relative to controls at 2 days of age
• at 2 days of age
• periods of apnea are shorter in duration than for controls
• peak ventilation response to hypoxia is significantly lower than for controls at 2 days but similar to controls at 8 days
• ventilation decline during hypoxia is less than for controls at both 2 and 8 days
• 16% larger ventilation values at 2 days of age than for controls

• latency to arouse after hypoxia is shorter than for controls at 2 days of age but similar to controls at 8 days
• movements during hypoxia and post hypoxia fail to increase as they do in controls

• mutants exhibit alterations of behavioral flexibility and adaptive behaviors coupled with unimpaired memory and anxiety
• mutants exhibit improved spatial learning in a modified cross maze with a food reward, learning the task more rapidly and reaching the goal more quickly than wild-type mice
• however, mutants do not exhibit memory or recognition impairments
• mutants do not show sensitization to novelty and do not react to drastic changes of maze configuration
• mutants do not adapt their displacements over time in the open field as the environment becomes more familiar as in wild-type mice which adapt their displacements from fast navigation at the periphery of an open field to slow displacements toward the center of the arena indicating lack of exploratory interest
• mutants exhibit different exploratory behavior than wild-type when two objects are placed in the environment, showing an absence of the reorganization of the transitions between sequences of actions seen in wild-type mice, indicating that mutants do not exhibit the adaptive processes of becoming familiar with the environment
• mutants, however do not differ in the time spent in the anxiogenic area of the light/dark device or for the number of transitions between both compartments, indicating normal anxiety level
• when faced with a social intruder of the same sex, mutants exhibit a higher rate of approach behaviors and lower rates of escape behaviors compared to wild-type mice, indicating disturbed social-interaction showing enhanced social interactions and an impaired capacity for interrupting ongoing behaviors

Contributing Projects:
Mouse Genome Database (MGD), Gene Expression Database (GXD), Mouse Models of Human Cancer database (MMHCdb) (formerly Mouse Tumor Biology (MTB), Gene Ontology (GO)
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last database update
MGI 6.14
The Jackson Laboratory