QUICK SEARCH:   [advanced] Author: Keyword(s):
Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents

This Article Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Services Email this article to a friend Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by ECKERT, R. Articles by FRIEDMAN, K. Search for Related Content PubMed PubMed Citation Articles by ECKERT, R. Articles by FRIEDMAN, K.

Journal of Experimental Biology 56,683-694 (1972)
Published by Company of Biologists 1972

Sensory Mechanisms in Paramecium : 1. Two Components of the Electric Response to Mechanical Stimulation of the Anterior Surface

R. ECKERT ¹, Y. NAITOH ¹, and K. FRIEDMAN ¹

¹ Department of Zoology and Brain Research Institute, University of California Los Angeles, California 90024

1. Specimens of Paramecium caudatum were stimulated mechanically with a piezoelectrically driven microstylus. Membrane potentials were monitored and intracellular polarizing currents were passed with glass microelectrodes.

2. Mechanical stimulation of the anterior 15% of the cell's length produced depolarizing transients in membrane potential. This ‘anterior response’ was amplitude-graded up to a maximum with stimuli of increasing intensities, and was accompanied by a drop in membrane resistance.

3. The anterior response consists of two components, a receptor potential in direct response to stimulus transduction, and a secondarily evoked regenerative component. Both are graded. With hyperpolarization of the cell membrane the regenerative component was suppressed and the receptor potential alone was seen. With hyperpolarization the size of the receptor potential was increased.

4. The regenerative component is identical with the ‘calcium response’ which is elicited by direct stimulation with injected depolarizing current. This conclusion is supported by similar sensitivity of the overshoot to extracellular concentrations of calcium, similar refractory periods, similar inactivation by depolarization and suppression by hyperpolarization, and similar prolongation of the time course by TEA.

5. It is concluded that local inflow of receptor current through the stimulated membrane of the anterior end depolarizes the cell membrane by electrotonic spread, activating the electrically excited calcium conductance of the membrane, and thereby eliciting the regenerative calcium response.

This article has been cited by other articles:

				V. Singla and J. F. Reiter The primary cilium as the cell's antenna: signaling at a sensory organelle. Science, August 4, 2006; 313(5787): 629 - 633. [Abstract] [Full Text] [PDF]