Effects of hydrostatic pressure on sensory discharge in frog semicircular canals

G. Zucca, L. Botta, E. Mira, M. Manfrin, A. Poletti, A. Buizza, P. Valli

Research output: Contribution to journalArticlepeer-review

Abstract

The effects of endolymphatic and perilymphatic pressure changes on resting and mechanically evoked responses were studied in isolated posterior semicircular canals of the frog. the results demonstrated that ampullar receptors are extremely sensitive to hydrostatic pressure changes (0.25 mm H20 were sufficient to produce distinct changes), being inhibited by endolymphatic pressure increases and facilitated by perilymphatic ones. Intracellular recordings from single afferent axons showed that the effects of hydrostatic pressure result from a modified transmitter release from the synaptic po'e of the hair cells. Unlike resting activity, mechanically evoked activity was always depressed in the presence of a hydrostatic pressure. This indicates that the sensitivity of ampullar receptors to mechanical stimuli, i.e. the gain of the conversion process, is maximal when no pressure is present between the inner and the outer fluid. the possible action of hydrostatic pressure on vestibular receptors is discussed.

Original languageEnglish
Pages (from-to)820-826
Number of pages7
JournalActa Oto-Laryngologica
Volume111
Issue number3
DOIs
Publication statusPublished - 1991

Keywords

  • Inner ear fluid pressures
  • Semicircular canals
  • Vestibular afferent activity

ASJC Scopus subject areas

  • Otorhinolaryngology

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