Meeting Abstract

P3.81  Thursday, Jan. 6  The Effects of GABA on the Isolated Crop-gizzard of the Earthworm Lumbricus terrestris KRAJNIAK, Kevin G.*; STASSI, Kory J.; YODER, Trent D.; Southern Illinois University Edwardsville; Southern Illinois University Edwardsville; Southern Illinois University Edwardsville kkrajni@siue.edu

Gamma amino butyric acid (GABA) is a neurotransmitter that is present in nerves innervating the earthworm digestive tract. Since we have been studying the regulation of crop-gizzard contractions in the earthworm, Lumbricus terrestris, we decided to examine the effects of GABA. The crop-gizzard was removed from an animal and placed in a tissue bath filled with worm saline. Mechanical movements were recorded with a Grass force transducer and displayed on a computer using Iworx Labscribe 2. The tissue was exposed to increasing concentrations of GABA and the resulting changes in contractions were used to create log-dose response curves. GABA caused a biphasic change in contraction amplitude. Amplitude increased with a threshold below 10^-9 M and decreased with a threshold of 10^-9 M. Frequency slightly decreased with a threshold of 10^-6 M. Thus it appears that GABA may be involved in the regulation of crop-gizzard motility in L. terrestris