55.1 Thursday, Jan. 5 FMRFamide Immunoreactivity and the Diffuse Nerve Net of Scyphozoan and Cubozoan Jellyfish SATTERLIE, Richard; University of North Carolina Wilmington email@example.com
Two diffuse nerve nets have been described, morphologically and physiologically, in the subumbrella of scyphomedsuae. These nets have mostly parallel distributions, and both appear to influence the swim musculature. One, the Motor Nerve Net (MNN), activates the swim muscles to produce swim contractions. The other, the Diffuse Nerve Net (DNN), appears to serve a modulatory role in alterning swim contractions. Similarly, the two nerve nets show different staining with immunohistochemical techniques--one is labeled with anitbodies to alpha or beta tubulin while the other is labeled with an antibody to FMRFamide. Distribution of stained neurons of both nets suggest the tubulin-immunoreactive net is the MNN while the FMRFamide-immunoreactive network is the DNN. Cubomedusase also show staining with both antibodies, and while the tubulin-immunoreactive networks are consistent with a MNN-like distribution (based on physiological examniation), the FMRFamide-immunorective networks are largely restricted to the centalized nervous system (rhopalia and nerve rings). If the FMRFamide-immunoreactive network retains its modulatory function, it suggests a centralization in which modulation of swimming activity has "moved" from the periphery in scyphozoans to a more centralized location in cubomedusae, most notably within the ganglion-like rhopalia.