Meeting Abstract

58.1  Tuesday, Jan. 6  A new perspective on the echinoderm nervous system: abundant histaminergic and FMRFaminergic-like cells in the sea cucumber Leptosynapta clarki HOEKSTRA, L.A.*; MOROZ, L.L.; HEYLAND, A.; Friday Harbor Labs; Indiana University ; Friday Harbor Labs; The Whitney Laboratory for Marine Bioscience, University of Florida; Friday Harbor Labs; University of Guelph lhoekstr@indiana.edu

Understanding of the echinoderm nervous system remains elusive. The semi-transparent, brooding sea cucumber Leptosynapta clarki provides a new opportunity for detailed description of echinoderm nervous system structure and function. Clear evidence for histaminergic and FMRFaminergic-like immunoreactivity is reported in several distinct cell types distributed throughout the holothurian body. Surprisingly, no significant evidence could be found to support a role for serotonin. Additionally, pharmacological tests show a strong, directed peristaltic response to the application of histamine. Together these data indicate a lack of any discrete subdivision of the echinoderm nervous system and suggest a function for histamine in this nervous system. Future research will focus on further describing the functional role of histamine and on understanding the molecular regulatory machinery underlying the histaminergic system.