Analysis Tools
mortality/aging
|
• a few homozygotes live up to 4 months or longer
|
|
• most homozygotes die by P21
|
behavior/neurological
| N |
• homozygotes respond normally to painful stimuli in their whisker pads as well as to pinching of their tail and foot
|
limb grasping
(
J:17195
)
|
• when hung by the tail, homozygotes draw their limbs in towards their bodies
|
|
• by P10, homozygotes display athetotic walking movements
|
|
• on a rotating dowel, homozygotes fail to maintain an upright posture and tumble off
|
|
• even at rest, the limbs are held in abnormal positions in relation to the trunk
|
nervous system
|
• homozygotes lack Ia muscle afferent projections to spinal motor neurons and have fewer large myelinated axons in the dorsal root and posterior columns of the spinal cord
|
|
• at P1, IHCs are devoid of innervation
• developmental analysis indicates that, at E16.5, some cochlear nerve fibers initially reach their peripheral targets but subsequently fail to maintain innervation and degenerate
• in contrast, the innervation pattern of OHCs appears normal
|
|
• at P1, a 51% reduction in cochlear ganglion neuron number is observed
• large-sized type I neurons (innervating IHCs) are preferentially lost (62% reduction), whereas small-sized type II neurons (innervating OHCs) remain unaffected
|
|
• by P1, a 16% reduction in vestibular ganglion neuron number is observed
• however, both vestibular ganglia and vestibular sensory epithelia are histologically normal and their innervation patterns appear unaffected
|
|
• newborn homozygotes show a 19% neuron loss in the lumbar dorsal root ganglia
|
hearing/vestibular/ear
|
• at P1, the cochlear sensory epithelium appears thinner and less stratified than normal
|
|
• at P1, IHCs are devoid of innervation
• developmental analysis indicates that, at E16.5, some cochlear nerve fibers initially reach their peripheral targets but subsequently fail to maintain innervation and degenerate
• in contrast, the innervation pattern of OHCs appears normal
|
growth/size/body
|
• although normal at birth, homozygotes exhibit reduced body size at P4
|
