Isolation of Neurons of a Nudibranch Veliger

A technique was developed to dissociate and culture identified sensory neurons and interneurons from the anterolateral propodial ganglia of metamorphically competent veligers of the nudibranch, Onchidoris bilamellata. Receptor cells have been represented as receiving an environmental cue that initiates the settlement response. The ganglionic cells, along with other cell-types from the propodial region housing the ganglia, were excised with a large-bore micropipette, and dissociated by mild trypsin incubation and trituration. Cells and tissues were plated in poly-L-lysine-coated plastic culture dishes containing modified Aplysia medium and survived for up to four days. The different cell-types possess diagnostic features, so they can be recognized under culture conditions. Sensory cells were bipolar in profile, with one end of the cell being thickened, representing the receptor apparatus. Interneurons are unipolar or bipolar in shape, and bear thin neurites. Other cell-types, including myocytes, ciliated epidermal cells, nonciliated epidermal cells, and gland cells were identified. Identifications of living cells were corroborated through electron microscopical analysis.