The studies conducted with support from NIH center on the neurophysiology and biochemistry of the bag cell neurons in Aplysia californica. Since previous studies have shown that the hormone produced by these cells is the end product of a complex post-translational processing, the studies to be conducted this year will focus on some of the important steps in this processing regimen. Specifically the membrane-associated early events will be explored by means of differential centrifugal separation of membranous organelles. Subsequent processing that leads to a solubility shift in the hormone will be examined as well. Additional studies will concern the amino acid composition and sequence of the hormone, and processes associated with the transductive coupling seen between membrane depolarization and protein synthetic activity in the cells.