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 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 JOSEPHSON, R. K. Search for Related Content PubMed Articles by JOSEPHSON, R. K.

Journal of Experimental Biology 38,579-593 (1961)
Published by Company of Biologists 1961

Repetitive Potentials Following Brief Electric Stimuli in a Hydroid

ROBERT K. JOSEPHSON ¹

¹ University of California Los Angeles

1. Electrical pulses (amplitude -0.05 to -15 mV.; duration 20-120 msec.) have been recorded from the stolon of Cordylophora lacustris following stimulation. These pulses are propagated with an average velocity of 2.7 cm./sec. at 22° C.

2. Brief electric shocks of little more than threshold intensity can evoke bursts of pulses. The number of pulses in a burst increases with stimulus intensity, but the shape and size of individual pulses do not.

3. Repetitive stimulation causes facilitation of both size of single pulses and number of pulses in a burst. Refractory period, if present, is variable. The minimum interval between two pulses is about 200 msec.

4. Mechanical stimulation evokes pulses identical to those evoked by electrical stimulation.

5. The greater the number of pulses recorded in the stolon near a polyp, the greater and faster is the contraction of that polyp.

6. The number of pulses, but not their individual sizes, decreases with increasing distance from the point of stimulation.

7. It is concluded that conduction in the stolon and the electrical pulses are due to nervous activity and that the conducting system is a network having interneural junctions which sometimes require to be facilitated.

This article has been cited by other articles:

				J. Thorpe, G. Shelton, and M. Laverack Colonial nervous control of lophophore retraction in cheilostome Bryozoa Science, July 4, 1975; 189(4196): 60 - 61. [Abstract] [PDF]

				R. K. Josephson and M. Macklin Transepithelial Potentials in Hydra Science, June 23, 1967; 156(3782): 1629 - 1631. [Abstract] [PDF]