Effects of different ionic environments on the mechano-sensitivity of lateral line organs in the mudpuppy
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The lateral line organ ofNecturus maculosus was stimulated with water vibrations, and the degree of synchronization between stimulus and afferent activity was related to the ionic composition of the external solution.
The mechano-sensitivity was a function of the Ca++ concentration of the external medium (Fig. 2). The organs were insensitive to vibrations in Ca++ free solution (containing Ca-chelating agents) (Fig. 5), whereas the sensitivity leveled off at a maximum value for concentrations above about 1 mM Ca++. The effect of Sr++ was similar to Ca++ (Fig. 4). K+ and Na+ also enhanced the mechano-sensitivity, but the effect of these ions was much less than for Ca++ (Fig. 3).
The mechano-sensitivity was suppressed by Mg++, Co++ and La+++ (Figs. 7, 8), the order of effectiveness being La+++≫ Co++> Mg++. The suppression decreased with increasing Ca++ concentration, suggesting that the effect of Ca++ is competitively blocked by these ions. The mechano-sensitivity was also suppressed by low pH (Fig. 9).
The different ions tested in the present study affected the generation of hair cell receptor potentials, and it is suggested that the inward depolarizing receptor current of hair cells in mudpuppy lateral line organs is mainly carried by Ca++.
KeywordsHair Cell Cell Receptor Lateral Line Ionic Composition External Medium
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- Blaustein, M. P.: Phospholipids as ion exchangers: Implications for a possible role in biological membrane excitability and anesthesia. Biochem. biophys. Acta (Amst.)135, 653–668 (1967)Google Scholar
- Castillo, J. del, Katz, B.: The membrane change produced by the neuromuscular transmitter. J. Physiol. (Lond.)125, 546–559 (1954)Google Scholar
- Flock, Å.: Sensory transduction in hair cells. In: Handbook of sensory physiology, vol. I (W. R. Loewenstein, ed.), p. 396–441. Berlin-Heidelberg-New York: Springer 1971Google Scholar
- Flock, Å., Russel, I.: Efferent nerve fibers: Postsynaptic action on hair cells. Nature (Lond.) New Biol.243, 89–91 (1973)Google Scholar
- Frishkopf, L. S., Liff, H., Oman, C. M.: Structure and motion of cupulae of lateral-line organs inNecturus maculosus: I. Introduction. Quart. Prog. Rep. No. 104, Res. Lab. Electr. M.I.T., 326–329 (1972)Google Scholar
- Frishkopf, L. S., Oman, C. M.: Structure and motion of cupulae of lateral-line organs inNecturus maculosus: II. Observations of cupular structure. Quart Prog. Rep. No. 104, Res. Lab. Electr. M.I.T., 330–331 (1972)Google Scholar
- Furukawa, T., Ishii, Y.: Neurophysiological studies on hearing in gold fish. J. Neurophysiol.30, 1377–1403 (1967)Google Scholar
- Grundfest, H.: Electrophysiology and pharmacology of different components of bioelectric transducers. Cold Spr. Harb. Symp. quant. Biol.30, 1–14 (1965)Google Scholar
- Hafemann, D. R.: Effects of metal ions on action potentials of lobster giant axons. Comp. Biochem. Physiol.29, 1149–1161 (1969)Google Scholar
- Hagiwara, S.: Ca spike. Advanc. in Biophys.4, 71–102 (1973)Google Scholar
- Hagiwara, S., Ozawa, S., Sand, O.: Voltage clamp analysis of two inward current mechanisms in the egg cell membrane of a starfish. J. gen. Physiol.65, 617–644 (1975)Google Scholar
- Hagiwara, S., Takahashi, K.: Surface density of calcium ions and calcium spikes in the barnacle muscle fiber membrane. J. gen. Physiol.50, 583–601 (1967)Google Scholar
- Harris, G. G., Frishkopf, L., Flock, Å.: Receptor potentials in the hair cells of mudpuppy lateral line. J. acoust. Soc. Amer.45, 300–301 (1969)Google Scholar
- Harris, G. G., Frishkopf, L., Flock, Å.: Receptor potentials from hair cells of the lateral line. Science167, 76–79 (1970)Google Scholar
- Hille, B.: Charges and potentials at the nerve surface. Divalent ions and pH. J. gen. Physiol.51, 221–236 (1968)Google Scholar
- Iurato, S.: Tectorial membrane. In: Submicroscopic structure of the inner ear. Oxford: Pergamon Press 1967Google Scholar
- Katsuki, Y.: The ionic receptive mechanism in the acousticolateralis system. In: Basic mechanisms in hearing (A. R. Møller, ed.), p. 307–334. New York: Academic Press 1973Google Scholar
- Kishimoto, U.: Repetitive action potentials inNitella internodes. Plant & Cell Physiol.7, 547–558 (1966)Google Scholar
- Liff, H. J., Shamres, S.: Structure and motion of cupulae of lateral-line organs inNecturus maculosus: III. A technique for measuring the motion of freestanding lateral-line cupulae. Quart. Prog. Rep. No. 104, Res. Lab. Electr. M.I.T., 332–336 (1972)Google Scholar
- Naitoh, Y.: Bioelectric basis of behaviour in protozoa. Amer. Zoologist14, 883–893 (1974)Google Scholar
- Naitoh, Y., Eckert, R.: Control of ciliary activity in protozoa. In: Cilia and flagella (M. Sleigh, ed.), p. 305–352. New York: Academic Press 1974Google Scholar
- Naitoh, Y., Eckert, R., Friedman, K.: A regenerative calcium response inParamecium. J. exp. Biol.56, 667–681 (1972)Google Scholar
- Obara, S.: Calcium dependent receptor potential of the electroreceptor of marine catfish. Proc. Japan Acad.50, 247–251 (1974)Google Scholar
- Obara, S., Bennett, M. V. L.: Mode of operation of ampullae of Lorenzini of the skate,Raja. J. gen. Physiol.60, 534–557 (1972)Google Scholar
- Oman, C. M.: Structure and function of cupulae of lateral-line organs inNecturus maculosus: IV. Preliminary model for the dynamic response of the freestanding lateral-line cupula based on measurements of cupula stiffness. Quart. Prog. Rep. No. 104, Res. Lab. Electr., M.I.T., 336–343 (1972)Google Scholar
- Oman, C. M., Frishkopf, L. S.: Neural responses of lateral-line organs inNecturus maculosus to direct mechanical stimulation. Quart. Prog. Rep. No. 108, Res. Lab. Electr., M.I.T., 332–338 (1973)Google Scholar
- Sand, O., Ozawa, S., Hagiwara, S.: Electrical and mechanical stimulation of hair cells in the mudpuppy. J. comp. Physiol.102, 13–26 (1975)Google Scholar
- Stillman, I. M., Gilbert, D. L., Lipicky, R. J.: Effect of external pH upon the voltage-dependent currents of the squid giant axon. Biophys. Soc. Ann. Meet. Abstr.11, 55a (1971)Google Scholar
- Weiss, T. F., Mulroy, M. J., Altmann, D.W.: Intracellular responses to acoustic clicks in the inner ear of the alligator lizard. J. acoust. Soc. Amer.55, 606–619 (1974)Google Scholar
- Yanagisawa, K., Taglietti, V., Katsuki, Y.: Responses to chemical stimuli in the hair cells of the lateral-line organ of mudpuppy. Proc. Japan Acad.50, 526–531 (1974)Google Scholar
- Zipser, B., Bennett, M. V. L.: Tetrodotoxin resistant electrically excitable responses of receptor cells. Brain Res.62, 253–259 (1973)Google Scholar