Meeting Abstract
P2.77 Friday, Jan. 4 The Sensory Physiology of Nematostella vectensis WATSON, G.M.; KINLER, K.M.; PHAM, L.N.; MIRE, P.*; Univ. of Louisiana, Lafayette; Univ. of Louisiana, Lafayette; Univ. of Louisiana, Lafayette; Univ. of Louisiana, Lafayette pmt9606@louisiana.edu
Nematostella vectensis has emerged as a model organism for Developmental Biology. We here report that Nematostella is vibration sensitive. Nematocyst discharge was assayed in the presence of vibrating glass probes. When touched with gelatin coated test probes Nematostella discharges microbasic p-mastigophore nematocysts into the gelatin coating. The nematocysts are counted for a single field of view at 400x using phase contrast optics. In the presence of vibrations, discharge of nematocysts significantly increases above baseline at specific �key� frequencies. In seawater alone, key frequencies occur at 36-37, 46-47, 51, 56 and 64 Hz. In the presence of 10-7 M N-acetylneuraminic acid (NANA), a downward shift in key frequencies is observed. Data thus far indicate NANA tuned frequencies occur at 2, 5, 11-12, 16,17 and 20 Hz. The downward shift in key frequencies is accompanied by an elongation of hair bundle mechanoreceptors on the tentacle epithelium. The hair bundles are composed of actin based stereocilia originating from supporting cells surrounding a single sensory neuron. Stereocilia from the supporting cells converge onto six to seven large diameter stereocilia originating from the sensory neuron. Electrophysiology confirms that the hair bundles are mechanoreceptors. Current transients occur in response to deflection of the hair bundles. The stimulus/response curve is asymmetrically sigmoid in seawater alone. Current transients are modified by the presence of 10-7 M NANA. Supported by NSF IOB0542574.
