Meeting Abstract

P2.86  Jan. 5  Sensory cells are denser in the lateral portion of the oral veil of Tritonia diomedea IGWE, OB*; CAIN, SD; MURRAY, JA; Friday Harbor Laboratories; Friday Harbor Laboratories; University of Central Arkansas tritoniadiomedea@mac.com

The nudibranch gastropod, Tritonia diomedea has proved to be an excellent candidate for investigating sensory integration and orientation mechanisms, due to its large identifiable neurons and easily accessible nervous system. The oral veil of Tritonia is used in orienting to tidal flow (positive rheotaxis), and nerve cuts implied that the lateral portion of the oral veil contained the receptors that discriminate water flow direction. Our goal was to investigate the presence and morphology of innervated ciliated sensory receptors located on the oral veil of Tritonia that might be used to detect flow direction. The medial oral veil does not seem capable of detecting flow direction, thus, we compared the lateral and medial oral veil regions, to attempt to distinguish different structures that might sense flow direction. Tritonia can sense touch, discriminate tastes, as well as detect flow direction with its oral veil. Thus, we expected to observe considerable similarity in sensory receptors between the lateral and medial portions. To visualize axons extending to the skin we used an antibody against alpha, beta-tubulin found in axons; these antibodies were fluorescently labeled. In addition, we labeled the tissue with an antibody to sensorin�a protein found in many sensory cells in gastropods. The lateral portion of the oral veil contained more innervated receptors at the epithelial layer relative to the medial portion (1.0 vs. 0.4 receptors per square micron; p< 0.05), which may be responsible for the ability of the lateral portion to sense flow direction. Further experiments will be needed to distinguish between touch, chemo- and flow receptors.