behavior/neurological
N |
• no apparent motor capability abnormalities
(J:116706)
• mice exhibit normal innate olfactory attractive or avoidance response, odor discrimination during habituation and dishabituation, and olfaction of general odors and pheromones
(J:170988)
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• freezing behavior between electrical foot shocks significantly increases during the fourth or fifth interval
• when placed back into the environment after 30 minutes of rest, the mice freeze for almost as twice as long as controls
• the enhanced fear memory persisted even after 10 days when wild-type mice have largely ceased the behavior
• mice are not more prone to exhibit a freezing behavior when introduced to a novel environment and have normal nociceptive responses
• intracerebroventricular administration of serotonin restores normal freezing behaviors
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• after completing a 9-day training period in a morris water maze, the mice spend less time in the target quadrant, take a longer time to cross the platform location, and cross the target location less frequently compared to controls
• the deficiences are more pronounced 10 days after training compared to 1 day after training
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• mice spend at least 20% more time in the open arm of an elevated-plus maze test than wild-type mice indicating reduced anxiety
• mice also have about half the latency time between novelty presentation and feeding than exhibited by control mice
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• male mice exhibit increased mounting of target male mice compared with control mice
• male mice spend less time sniffing the female genital odor and more time sniffing the male genital odor compared with control mice
• male mice spend less time above male bedding and less time above female bedding compared with control mice
• male mice fail to exhibit an increase in mounting estrous female unlike wild-type mice
|
• male mice exhibit increased ultrasonic vocalization towards males compared with control mice
• however, male mice vocalization towards female are normal
|
nervous system
N |
• expression levels of dopamine, dihydroxyphenyacetic acid, and norepinephrine in the brain and spinal cord are similar to control mice
|
• cytoarchitecture of the B1-B9 raphe nuclei is abnormal with the B6 nuclei (caudal nucleus raphe dorsalis) being absent
(J:116706)
• serotonin-producing neurons are absent in the raphe magnus nucleus
(J:139720)
• the distribution and density of tyrosine hydroxylase-positive neurons were unchanged
(J:139720)
|
• at E12.5 serotonin staining is reduced and by E14.5 very few serotonin positive neurons are present in the brain
• in adult mice, only rare serotonin positive cells are found in raphe nuclei and no ascending or descending fibers are found in the rostral brain or spinal cord
• loss of serotonin cells appears to occur during postnatal stages
• however, no ectopic serotonin neurons are found and peripheral serotonin expression is similar to wild-type mice
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• foot shock impairs subsequent hippocampal CA1 LTP responses in wild-type mice but not these mice as measured by fEPSP amplitude
• serotonin administration to hippocampal slices restores LTP responses
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• foot shock impairs subsequent hippocampal CA1 LTD responses in wild-type mice but not these mice as measured by fEPSP amplitude
|
• adult mice lack essentially all central serotonin-producing neurons
• levels of serotonin are 10-fold lower than that of wild-type mice in the hippocampus, cortex, and striatum
• the levels of cells producing serotonin in the brain is 1% that of wild-type
the levels of cells producing serotonin in the brain is 1% that of wild-type
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taste/olfaction
N |
• mice exhibit normal innate olfactory attractive or avoidance response, odor discrimination during habituation and dishabituation, and olfaction of general odors and pheromones
|