ABSTRACT
Bioluminescence is a widespread phenomenon in the marine environment. In ophiuroids, it was observed that the control mechanisms of light emission differ between species (e.g. neurotransmitters and second messengers). Although there are heterogeneities in the signal transduction pathways leading to photogenesis, the requirement of extra-cellular calcium to induce light emission is conserved in all the species studied so far. In a previous study, it has been shown that the removal of calcium from the artificial seawater nearly completely abolished luminescence. Further pharmacological characterization indicated that the calcium channels involved in the luminescence control seem to be of L-type, voltage-gated in Amphiura filiformis and in Ophiopsila californica. Another uncharacterized channel type could be involved in Ophiopsila aranea. The aim of this work is to study the properties of ionic channels involved in the photogenesis using electrophysiological techniques (microspectrofluorometry and Patch-clamp) on the luminous cells (photocytes). Microspectrofluorometry indicated that intracellular calcium variations occurred in photocytes and patch-clamp allows us to identify the currents at photocyte’s membrane level.
