spacer gif spacer gif spacer gif spacer gif spacer gif
QUICK SEARCH:   [advanced]


spacer gif
     Home     Help     Feedback     Subscriptions     Archive     Search     Table of Contents    

This Article
Right arrow Full Text (PDF)
Right arrow Alert me when this article is cited
Right arrow Alert me if a correction is posted
Services
Right arrow Email this article to a friend
Right arrow Similar articles in this journal
Right arrow Alert me to new issues of the journal
Right arrow Download to citation manager
Right arrow reprints & permissions
Citing Articles
Right arrow Citing Articles via Google Scholar
Google Scholar
Right arrow Articles by DUBAS, F.
Right arrow Articles by BOYLE, P.R.
Right arrow Search for Related Content
PubMed
Right arrow Articles by DUBAS, F.
Right arrow Articles by BOYLE, P.R.
Journal of Experimental Biology 117,415-431 (1985)
Published by Company of Biologists 1985

Chromatophore Motor Units in Eledone Cirrhosa (Cephalopoda: Octopoda)

F. DUBAS 1 and P.R. BOYLE 2

1 Department of Zoology, University of Aberdeen, Aberdeen AB9 2TN, Great Britain; The Marine Biomedical Institute, The University of Texas Medical Branch, 200 University Boulevard, Galveston, Texas 77550. U.S.A
2 Department of Zoology, University of Aberdeen Aberdeen AB9 2TN, Great Britain

Innervation of chromatophore muscles of the octopus Eledone cirrhosa was investigated by stimulating nerve bundles in the skin with a suction electrode and monitoring chromatophore movements with a photo-cell or a video camera. Attention was focused on the organization of the chromatophore muscle fibres into motor units. Individual muscle fibres respond to single electrical impulses with twitch-like contractions that do not facilitate with repetition, but summate to a smooth tetanus at about 10–15 Hz. At tetanic frequency, the degree of expansion of single chromatophores is always maximal. However, the number of expanded chromatophores can be graded by variations of either the stimulus voltage or frequency. Individual chromatophores and probably individual muscle fibres are part of several motor units. Chromatophores forming a given motor unit are found among chromatophores served by other motor axons. The motor units apparently form precise parts of natural patterning.

Key words: Molluscan muscles, chromatophores, nervous control, octopus, Eledone cirrhosa

Accepted on January 14, 1985






© The Company of Biologists Ltd 1985