Meeting Abstract

P1.129  Tuesday, Jan. 4  Mucociliary interactions in the foot of the sea slug Tritonia diomedea TAHIR, U; SCHROER, ML; MURRAY, JA; CAIN, SD*; Georgia State U; Northern Arizona U; Cal. State U. East Bay; Eastern Oregon U shaun.cain@eou.edu

Mucociliary interactions are important in many physiological processes in a variety of tissues, e.g. human respiratory epithelial cells must maintain a balance of mucus and cilia beating to remove foreign particles and toxins. To study the neural systems the mucociliary interaction we used the common neuroethological model system, Tritonia diomedea. The entire pedal epithelium of this animal is covered in cilia, whose rhythmic beating propels its locomotion. We bath applied ACh to foot tissue and quantified the mucus secretion. We then fluorescently-labeled the enzyme responsible for the synthesis of ACh, Choline Acetyltransferase (ChAT), in foot tissue, ciliated grooves of the lateral tips of the oral veil, as well as the brain, and buccal ganglia. Finally, given the importance of ACh in muscle contraction, we labeled filamentous actin in the foot of T. diomedea to explored the possibility of an ACh-induced muscle contractions causing secretion. Exposure to every concentration of ACh induced an increased volume of mucus secretion. Mucus secretion decreased during the post-experimental wash, after exposure to the lower concentrations (0.01µM ACh and 0.1µM ACh), but it increased after exposure to the higher concentrations (1.0 µM ACh and 10.0 µM ACh). We suspect that this is due to a dilution effect. No filamentous actin was labeled in association with mucus glands or goblet cells in this experiment. As a result, we are unable to confirm the hypothesis that ACh-induced muscle contraction around these secretory cells is responsible for the mucus secretion from the foot. We observed no clear labeling of ChAT in any of the peripheral tissues experiment, but we observed numerous neurites and a few somata in consistent locations in the brain and buccal ganglia.