The discharge of cnidae, the stinging cells of cnidaria, requires that appropriate and concomitant chemical and mechanical stimuli be received. The goals of this research are to elucidate the cellular and molecular mechanisms whereby supporting cells in the tentacles of sea anemones chemosensitize adjacent cnidocytes to discharge cnidae in response to triggering mechanical stimuli. Experiments have been designed to test critical aspects of a comprehensive model of chemosensitization. The model proposes plausible functional relationships among the currently identified components of the chemosensitizing system of the cnidocyte- supporting cell complex. Essential features of the model are: 1) Chemoreceptors and sensitizing systems are located on supporting cells. 2) The chemosensitizing system primes the triggering contact mechanoreceptor by simultaneously elevating intracellular levels of calcium and depolarizing the cell membrane, and 3) Supporting cells are coupled to adjacent cnidocytes. This study of the mechanisms controlling the discharge of the stinging cells of sea anemones will yield valuable insights into cellular and molecular mechanisms of sensory transduction, stimulus-secretion coupling, intracellular sensory integration, and intercellular communication in these relatively primitive multicellular organisms. It should, further, provide new approaches to studying symbioses between animals of this and other groups of animals, and new information about the mechanism of self recognition in cnidarian species. In addition, the results of this research may suggest ways of protecting humans from the stings of sea anemones and jellyfish.
