Meeting Abstract
P2.167 Saturday, Jan. 5 The Effects of APKQYVRFamide and other FMRFamide Related Peptides on the Isolated Crop-Gizzard of the Earthworm Lumbricus terrestris. CORNWELL, F.J.*; BRAUER, C.L.; KRAJNIAK, K.G.; Southern Illinois Univ. Edwardsville; Southern Illinois Univ. Edwardsville; Southern Illinois Univ. Edwardsville fcornwe@siue.edu
The digestive tract of the earthworm Lumbricus terrestris responds to a variety of neurotransmitters including FMRFamide and its related peptides (FaRPs). Recently we identified the first earthworm FaRP, APKQYVRFamide, from the genes of Lumbricus rubellus. The goal of this project was to examine the effects of this peptide and structurally similar peptides on the crop-gizzard of L. terrestris. The crop-gizzard of the worm was removed and placed into a bath filled with worm saline. All movements of the crop-gizzard were recorded with a Grass force transducer and were displayed on a computer using Iworx Labscribe 2. Increasing concentrations of peptide were added to the bath and adequate time was allowed for each to take effect. The resulting changes in contractions were used to create log-concentration response curves. APKQYVRFamide caused a concentration dependent decrease in contraction amplitude with a threshold of 10-6M, while FMRFamide caused the same response with a threshold of 10-8 M. Since the earthworm peptide contains a tyrosine (Y) in place of the phenylalanine (F) in FMRFamide, we also challenged the tissue with YMRFamide, a FaRP found in leeches. YMRFamide caused a dose-dependent decrease in amplitude with a threshold of 10-6M. These results suggest that APKQYVRFamide may play a role in controlling the motility of the earthworm crop-gizzard. They also indicate that receptor prefers F instead of Y in the fourth position from the C-terminus.
