Chemoreceptors Regulate Discharge of Microbasic p-mastigophores in the Sea Anemone, AIPTASIA PALLIDA

Recently, using cnida-mediated measurements of adhesive force, Thorington and Hessinger (1984, 1988a, b) identified two different chemoreceptors involved in triggering cnida discharge on the tentacles of the sea anemone, Aiptasia pallida. These two classes of receptors were shown to interact with glycine and N-acetylneuraminic acid (NANA). We now show that the discharge of the microbasic p-mastigophores, one of the three types of cnidae present on the tentacles of A. pallida, is under the controlling influence of these two classes of cnidocyte-associated chemoreceptors. We also demonstrate that the number of discharged microbasic p-mastigophores adhering to the test probes is proportional to and linearly related to a component of the measured adhesive force. Our findings, thus, validate using measurements of adhesive force as indicators of the relative extents of cnida discharge. Furthermore, we calculate that the contribution to adhesive force made by a single mastigophore is approximately 0.17 mgf