title: Ionic composition of the endolymph and sensory transduction in labyrinthine organs.
abstract: The role of various ions in stimuli conversion has been investigated in isolated frog semicircular canals, by replacing the endolymph with solutions deprived in turn of Na+, K+, Cl- and Ca++. Mechanical and electrical stimuli were employed and slow ampullar and nerve potentials were recorded, together with the afferent discharge of impulses in the eighth nerve. The results support evidence that K+ is the carrier of the receptor current, as postulated in Davis' hypothesis, while Ca++ is essential in the processes which allow the current to be modulated during cupula deflections and therefore endon hair cells with mechanical sensitivity.
mesh_terms: D000161:Acoustic Stimulation; D000200:Action Potentials; D000818:Animals; D001001:Anura; D002118:Calcium; D002713:Chlorine; D004558:Electric Stimulation; D004710:Endolymph / Q000502:physiology*; D005071:Evoked Potentials; D007477:Ions; D007761:Labyrinthine Fluids / Q000502:physiology*; D011188:Potassium; D011893:Rana esculenta; D012665:Semicircular Canals / Q000502:physiology*; D012964:Sodium; D000159:Vestibulocochlear Nerve / Q000502:physiology*
chemical_list: D007477:Ions; D002713:Chlorine; D012964:Sodium; D011188:Potassium; D002118:Calcium