Meeting Abstract

P1.166  Wednesday, Jan. 4  Further Investigation of the Effects of Putative Neurotransmitters on the Body Wall of Lumbricus terrestris KRAJNIAK, K*; NEAL, M; Southen IL Univ. Edwardsville; Southern IL Univ. Edwardsville kkrajni@siue.edu

Previous studies have suggested that putative neurotransmitters modulate body wall contractions of L. terrestris. To investigate body wall modulation, a dorsal strip of 10 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. Dopamine decreased contraction frequency at a threshold of 10 nM, and increased at a threshold range of 1 nM. Dopamine increased contraction amplitude at a threshold of 10 nM, and decreased at a threshold of 1 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. Epinephrine decreased contraction rate and increased contraction amplitude at a threshold concentration of 1.0 nM. Norepinephrine increased contraction frequency and amplitude at a threshold concentration of 0.1 to 1.0 µ M and 1.0 to 10 mM. GABA decreased contraction frequency at a threshold of 1.0 nM. GABA did not significantly change contraction amplitude. FMRFamide increased both contraction frequency and amplitude at a threshold of 0.1 µ M.