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 Google Scholar Google Scholar Articles by STEPHENS, P. J. Search for Related Content PubMed Articles by STEPHENS, P. J.

Journal of Experimental Biology 123,217-228 (1986)
Published by Company of Biologists 1986

Electrical and Chemical Synapses Between Giant Interneurones and Giant Flexor Motor Neurones of the Hermit Crab (Pagurus Pollicaris)

PHILIP J. STEPHENS ¹

¹ Marine Biological Laboratories, Woods Hole, MA 02543 and Villanova University, Department of Biology, Villanova, PA 19085, USA

Address for reprint requests

1. An examination is made of the characteristics of the synapses between the single pair of giant interneurones (GIs) and the giant flexor motor neurones (GFMNs) in the fused thoracic-abdominal (TA) ganglion of the hermit crab Pagurus pollicaris.

2. There is an electrical synapse between each GI and its ipsilateral GFMN. Evidence for this includes (a) dye (Lucifer Yellow CH) coupling between the two neurones, (b) a short synaptic (0.2 ms) delay between spikes in the two axons, (c) the ability to pass hyperpolarizing current between the two neurones and (d) the sensitivity of the connection to bath applications of N-ethylmaleimide. This synaptic connection is rectifying, since a GFMN spike does not provoke an action potential in the GI.

3. There is a connection between the GI and the contralateral GFMN. Data indicating that this synaptic connection is chemical includes (a) a synaptic delay of between 0.6 and 0.8 ms, (b) transmission i9 easily and irreversibly fatigued, (c) the synapse is insensitive to N-ethylmaleimide and (d) there is no dye coupling between the two neurones.

4. Branches of the GFMN come in close proximity with the GI on both sides of the TA ganglion. However, it is not known whether there is a direct connection or an intervening neurone between the GI and the contralateral GFMN.

Key words: crab, flexor muscles, synapses

Submitted on February 13, 1986