hearing/vestibular/ear
N |
• mice exhibit normal distortion product otoacoustic emissions and synaptic-membrane turnover in inner hair cells despite the inability to load and release glutamate
• mice exhibit normal inner hair cell-afferent synapses
|
• a few scattered inner hair cells are missing (less than 1% of the total number) compared to in wild-type mice
|
• the number of lateral efferent endings is decreased 70% in the basal turn and 43% in the medial turn compared to in wild-type mice
|
• at 3 months, the number of presynaptic ribbons at the inner hair cell synapse is reduced compared to in wild-type mice
|
• calcium ion currents in inner hair cells are greater than in wild-type cells
|
• electrically stimulated auditory brainstem response amplitude is slightly reduced compared to in wild-type mice
|
• mice fail to exhibit sound-evoked auditory brainstem response (ABR) unlike wild-type mice
• however, mice exhibit normal electrically stimulated ABR unless treated with TTX
|
• mice fail to show any visible compound action potential response, even for stimulus intensities of 100 dB SPL
• however, mice exhibit normal membrane capacitance and summating potential amplitude intensity functions
|
behavior/neurological
• induced horizontal activity was markedly higher in mutant mice than in control after administration of cocaine
|
• decreased sensitivity of mutant mice to haloperidol as measured by induced catalepsy
|
• hyperactive in home cage measured by spontaneous horizontal locomotor activity
• no major histological changes were detected in the brains
• none of the sensorimotor skills, fine motor coordination and reflexes were impaired
|
nervous system
• a few scattered inner hair cells are missing (less than 1% of the total number) compared to in wild-type mice
|
• the number of lateral efferent endings is decreased 70% in the basal turn and 43% in the medial turn compared to in wild-type mice
|
• at 3 months, the number of presynaptic ribbons at the inner hair cell synapse is reduced compared to in wild-type mice
|
• calcium ion currents in inner hair cells are greater than in wild-type cells
|
• mice fail to show any visible compound action potential response, even for stimulus intensities of 100 dB SPL
• however, mice exhibit normal membrane capacitance and summating potential amplitude intensity functions
|
• the number of spiral ganglion is reduced 42% compared to in wild-type mice without evidence of degeneration
|
• a slightly increased turnover of acetylcholine in the striatum
• reduced ACh release evoked by the glutamatergic agonist NMDA in mutant brain slices
|
• the loss of a synergistic effect of glutamate on vesicular acetylcholine uptake
|
Mouse Models of Human Disease |
DO ID | OMIM ID(s) | Ref(s) | |
autosomal dominant nonsyndromic deafness 25 | DOID:0110555 |
OMIM:605583 |
J:139493 |