Meeting Abstract

P3.100  Thursday, Jan. 6  The Effects of Several Putative Neurotransmitters on the Body Wall of Lumbricus terrestris NEAL, Michael W.*; KRAJNIAK, Kevin G.; Southern Illinois University Edwardsville nealwesley@yahoo.com

Previous studies have shown that the body wall electrical activity can be modulated by various neurotransmitters and neuropeptides. Since our lab has been examining the effects of neurotransmitters on annelid smooth muscle, we decided to develop an assay to examine the mechanical changes in the body wall by these same agents. Body wall modulation, a dorsal strip of 15 segments anterior to the clitellum was removed from the animal and placed in a tissue bath. Contractions were measured with a force transducer, and analyzed with LabScribe. The tissue was exposed to increasing concentrations of the neurotransmitter of choice, and the resulting changes in contractions were used to create log-dose response curves. 5-hydroxytryptamine increased contraction frequency and decreased contraction amplitude at a threshold of 10 nM. Acetylcholine decreased contraction frequency and increased contraction amplitude at a threshold of 10 nM. Octopamine had no significant biological effect on contraction frequency and amplitude. FMRFamide increased both contraction frequency and amplitude at a threshold of 0.1 µM. We are exploring the effects of epinephrine, norepinephrine, and GABA on the body wall.