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 MOULINS, M. Articles by NAGY, F. Search for Related Content PubMed Articles by MOULINS, M. Articles by NAGY, F.

Journal of Experimental Biology 90,205-230 (1981)
Published by Company of Biologists 1981

Participation of an Unpaired Motor Neurone in the Bilaterally Organized Oesophageal Rhythm in the Lobsters Jasus Lalandii and Palinurus Vulgaris

M. MOULINS ¹ and F. NAGY ¹

¹ Laboratoire de Neurobiologie Comparée, CNRS et Université de Bordeaux I, 2 rue du Professeur Jolyet, 33120 Arcachon, France

1. The main oesophageal motor neurone (OD₁) of the rock lobster is an unpaired bifurcating nerve cell. The cell body is located in the oesophageal ganglion and the left and right axonal branches pass through the left and right commissural ganglia to innervate all the oesophageal dilator muscles.

2. Three types of potentials are recorded in the cell body in vitro; each type is associated with an extracellular spike recorded from the nerves connecting the ganglia.

3. Comparison between the three types of potentials (and the extracellular spikes) and collision experiments shows that all three are spikes.

4. Spontaneous collisions can sometimes occur and it is concluded that one spike is generated in the oesophageal ganglion (somatofugal a-spike) while the other two are generated in the left commissural ganglion (somatopetal c-spike) or the right commissural ganglion (somatopetal c-spike).

5. Each spike initiating zone is synaptically driven.

6. The commissural zones fire short phasic bursts; each burst is composed of only one type of spike (b- or c-). The oesophageal (a-) zone gives a tonic discharge interrupted when the other zones are firing. Finally, combined firing of the spike initiating zones can generate three different patterns of discharge.

7. OD¹ participates in the oesophageal motor rhythm produced by two oscillators (one in each commissural ganglion) which fire alternated series of bursts.

8. It is concluded that the three axonal spike initiating zones enable the motor neurone (1) to follow the oesophageal motor rhythm at any time regardless of which oscillator is in operation and (2) to co-ordinate phasic and tonic activation of the oesophageal dilator muscles.