Ultrastructure of the retinal synapses in cubozoans

UNCW Author/Contributor (non-UNCW co-authors, if there are any, appear on document)
Gregory Clark Gray (Creator)
Institution
The University of North Carolina Wilmington (UNCW )
Web Site: http://library.uncw.edu/
Advisor
Richard Satterlie

Abstract: Cubomedusae (box jellyfish) are well known for their strong directional swimming and responses to visual stimuli, and they have complex lensed eyes comparable to those of higher multicellular animals. Cubomedusae possess a total of 24 eyes that are of four morphologically different types, yet little is known about the neural organization of their eyes. The eyes are located on ganglion-like structures called rhopalia – each of the four rhopalia contains an upper and a lower lensed eye (with a cornea, lens and retina), two pit ocelli, and two slit ocelli. Using transmission electron microcopy, the synaptic morphology of the eyes and pacemaker region of four species of cubozoans (Carybdea alata, Carybdea marsupialis, Tripedalia cystophora, and Chiropsalmus quadrumanus) were examined. Similarities in unique invaginated synaptic structures were found in all four species, but only in their upper and lower lensed eyes. Density measurements indicated that the invaginated synapses are located in close proximity to the basal region of photoreceptor cells, and size differences of invaginated synapses were observed between the upper and lower lensed eyes, as well as between species. Four additional types of chemical synapses: clear unidirectional, dense core unidirectional, clear bidirectional, and clear and dense core bidirectional were also observed in the rhopalia of these four species. Results from this study raise the possibility that invaginated synapses may be useful in sorting out the neural circuitry in the upper and lower lensed eyes of these four species.

Additional Information

Publication
Thesis
A Thesis Submitted to the University of North Carolina at Wilmington in Partial Fulfillment of the Requirement for the Degree of Masters of Science
Language: English
Date: 2009
Keywords
Cubomedusae--Anatomy, Jellyfishes--Anatomy
Subjects
Jellyfishes -- Anatomy
Cubomedusae -- Anatomy