ERDMANN, C.G.; CAIN, S.D.; Friday Harbor Labs, Univ. of Washington; Friday Harbor Labs, Univ. of Washington: C-Fos-like immunoreactivity in the nervous system of the nudibranch mollusc Tritonia diomedea

In the sea slug Tritonia diomedea, the morphology and accessibility of the brain has allowed researchers to use sharp electrodes to record intracellularly from as many as eight different, individually identifiable neurons simultaneously. These recordings can be done on nearly intact animals while they perform a variety of behaviors, such as swimming, feeding, and copulation. These attributes, coupled with T. diomedea’s relatively small central nervous system (comprised of ~ 7000 neurons), have made this animal an important organism in which to study the neural control of behavior. Although the use of single sharp-electrode recordings has contributed greatly to our understanding of nervous control of behavior, several studies have shown the importance of ensemble neuronal activity in undrstanding the role of neural circuits during behavior. With the exception of a few purely reflexive behaviors, behavioral circuits typically contain several cells within the CNS, even a simple system such as T. diomedea. Identification of nearly complete circuits has therefore been difficult, if not impractical. One method for identifying cells within a neural circuit is to identify immediate early genes that are up-regulated when the circuit is activated. In this study, we attempted to identify C-Fos (product of an immediate early gene) within the CNS of T. diomedea. Preliminary results of western blotting suggest that T. diomedea has a C-Fos of ~ 45K MW. If this result is confirmed, we will be able to use this protein as a marker for identifying cells in behavioral circuits such as swimming and magnetic orientation behavior in T. diomedea.