Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
1
pubmed:dateCreated
1993-3-4
pubmed:abstractText
The results of immunocytochemical, enzymatic and electrophysiological studies have indicated that acetylcholine and GABA may act as neurotransmitters in lateral olivocochlear efferent endings on inner hair cell afferent dendrites. Since spike activity can be recorded in the dendritic region of inner hair cells, microiontophoretic techniques were used testing the possible neurotransmitter candidates, acetylcholine and GABA, on spontaneous and induced firing of the afferent dendrites. The experiments were carried out in anaesthetised guinea-pigs, the third and fourth turns of the cochlea being exposed for electrode penetration. Ejection of acetylcholine resulted in a pronounced dose-dependent increase in subsynaptic spiking activity. Furthermore, acetylcholine enhanced glutamate-induced activity. In contrast, even at high doses, GABA had very little effect on the spontaneous cochlear firing rate. When the firing rate had first been enhanced by glutamate or N-methyl-D-aspartate, however, this activation could be reduced by the ejection of GABA. A similar reduction was observed when the firing rate had been enhanced with acetylcholine. The results of our studies support the hypothesis that these substances are involved in efferent neurotransmission on inner hair cell afferent fibres. It should be pointed out, however, that besides acetylcholine and GABA, several opioids such as enkephalins and dynorphins seem to be involved in efferent cochlear innervation.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Dec
pubmed:issn
0378-5955
pubmed:author
pubmed:issnType
Print
pubmed:volume
64
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1-5
pubmed:dateRevised
2007-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
The efferent modulation of mammalian inner hair cell afferents.
pubmed:affiliation
Division of Neurobiology, University of Berne, Switzerland.
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't