Meeting Abstract

P2.87  Jan. 5  Ultrastructure of the Retinal Synapses in Cubozoans GRAY, G. Clark*; SATTERLIE, Richard A.; University of North Carolina Wilmington; University of North Carolina Wilmington gcg4757@uncw.edu

Cubozoans have evolved complex eyes comparable to that of higher multicellular animals. Two complex eyes are located on each of the four rhopalia which, in addition, contain a statolith, two slit shaped ocelli, and two pit shaped ocelli. In the complex eyes, photoreceptor cells form axons that feed into a neural layer located just below the photoreceptor cell bodies. In our attempt to sort out the circuitry of this neural layer, we have found unique invaginated synapses associated with photoreceptor cells. The pre-synaptic terminals include fine tubular processes about 0.11&microm to 0.14&microm in diameter which invaginate into the pre-synaptic photoreceptor processes to a depth of about 0.23&microm. Clear vesicles of about 0.08&microm in diameter are found in the pre-synaptic terminal surrounding the invaginated process. Using electron microscopy and immunohistochemistry, sections of the eyes of four species of box jellies were examined to determine if these unique synapses were only associated with the photoreceptor cells. Using these unique synapses as markers, we are beginning to sort out the organization of the underlying neural connections in the retinas in these complex eyes.