Preferential expression of transient potassium current (I(A)) by 'short' hair cells of the chick's cochlea

B. W. Murrow, P. A. Fuchs

Research output: Contribution to journalArticle

Abstract

We have made a comparative study of the membrane properties of tall and short hair cells isolated from a selected region of the chick's cochlea. Tall hair cells are analogous to inner cochlear hair cells of mammals, and like those, are presynaptic to the majority of afferent neurons in the cochlea. Short hair cells, like mammalian outer hair cells, are the postsynaptic targets of efferent neurons that inhibit the cochlea. Voltage-clamp recordings have revealed that short hair cells have an inactivating potassium (K) current, I(A), whereas tall hair cells have little or none. Short hair cells are also sensitive to the cholinergic agonist carbachol, whereas tall hair cells are not. This pattern is in accord with the selective distribution of efferent cholinergic synapses in the cochlea. Although I(A) is completely inactivated at the resting potential of the short hair cells, cholinergic agonists can hyperpolarize these cells by as much as 30 mV. This hyperpolarization removes inactivation and allows I(A) to modulate subsequent voltage-dependent processes in short hair cells. It is concluded that I(A) could increase the high frequency response of the hair cell by decreasing membrane resistance and thus the membrane time constant after inhibition. This will be of particular importance to cochlear function if short hair cells produce voltage-dependent movements, as do mammalian outer hair cells.

Original languageEnglish (US)
Pages (from-to)189-195
Number of pages7
JournalProceedings of the Royal Society B: Biological Sciences
Volume242
Issue number1305
DOIs
StatePublished - Jan 1 1990
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry, Genetics and Molecular Biology(all)
  • Immunology and Microbiology(all)
  • Environmental Science(all)
  • Agricultural and Biological Sciences(all)

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