Linked Life Data

16828974

Source:http://linkedlifedata.com/resource/pubmed/id/16828974

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
4
pubmed:dateCreated
2006-8-21
pubmed:abstractText
Cochlear inner hair cells (IHCs) release neurotransmitter onto afferent auditory nerve fibers in response to sound stimulation. Normal development and function of inner hair cells require the expression of alpha subunit 1.3 forming L-type voltage-gated Ca(2+) channel (Ca(V)1.3). Here, we used immunohistochemistry and reverse transcription-polymerase chain reaction to study the synaptic organization and expression of large conductance Ca(2+)-activated potassium channels in IHCs of mice lacking the Ca(V)1.3 Ca(2+) channel (Ca(V)1.3(-/-)). Despite the near complete block of evoked afferent synaptic transmission, hair cell ribbon synapses were formed and remained preserved for at least 4 weeks after birth. Moreover, these "silent" afferent synapses held major components of the synaptic machinery such as Bassoon, Piccolo, and CSP. Hence, the block of exocytosis might be solely attributed to the lack of Ca(2+) influx through Ca(V)1.3 channels. Later on, Ca(V)1.3 deficient IHCs subsequently lost their afferent synapses. This was probably due to a secondary degeneration of the postsynaptic spiral ganglion neurons. In line with a prolonged efferent synaptic transmission onto Ca(V)1.3 deficient IHCs, which normally ceases around onset of hearing, we found juxtaposed immunoreactive spots of efferent presynaptic synaptophysin and postsynaptic (IHCs) small conductance Ca(2+)-activated potassium channels (SK channels) up to six weeks after birth. Finally, we show a substantial reduction of mRNA for the alpha subunit of the large conductance Ca(2+)-activated potassium channel (BK) in the apical cochlea, suggesting a reduced transcription of its gene in Ca(V)1.3 deficient IHCs. Ca(V)1.3 deficient IHCs lacked the apical spot-like immunoreactivity of clustered BK channels, which normally contribute to the temporal precision of hair cell afferent synaptic transmission. In summary, these data indicate that the Ca(V)1.3 channels are crucially involved in regulation of the expression of BK and SK channels. Ca(V)1.3 channels seem not to be essential for ribbon synapse formation, but are required for the maintenance of ribbon synapses and spiral ganglion neurons.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Sep
pubmed:issn
0306-4522
pubmed:author
pubmed:issnType
Print
pubmed:day
15
pubmed:volume
141
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1849-60
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed-meshheading:16828974-Age Factors, pubmed-meshheading:16828974-Animals, pubmed-meshheading:16828974-Animals, Newborn, pubmed-meshheading:16828974-Blotting, Northern, pubmed-meshheading:16828974-Calcium Channels, L-Type, pubmed-meshheading:16828974-Cochlea, pubmed-meshheading:16828974-Gene Expression Regulation, Developmental, pubmed-meshheading:16828974-Hair Cells, Auditory, Inner, pubmed-meshheading:16828974-Immunohistochemistry, pubmed-meshheading:16828974-Large-Conductance Calcium-Activated Potassium Channel..., pubmed-meshheading:16828974-Membrane Glycoproteins, pubmed-meshheading:16828974-Mice, pubmed-meshheading:16828974-Mice, Inbred C57BL, pubmed-meshheading:16828974-Mice, Knockout, pubmed-meshheading:16828974-Protein Subunits, pubmed-meshheading:16828974-RNA, Messenger, pubmed-meshheading:16828974-Receptors, Glutamate, pubmed-meshheading:16828974-Reverse Transcriptase Polymerase Chain Reaction, pubmed-meshheading:16828974-Synapses, pubmed-meshheading:16828974-Synaptophysin
pubmed:year
2006
pubmed:articleTitle
Synaptic organization in cochlear inner hair cells deficient for the CaV1.3 (alpha1D) subunit of L-type Ca2+ channels.
pubmed:affiliation
Department of Otolaryngology and Center for Molecular Physiology of the Brain, University of Göttingen Medical School, D-37099 Göttingen, Germany.
pubmed:publicationType
Journal Article, Comparative Study, In Vitro, Research Support, Non-U.S. Gov't