Localization of the neuropeptide NGIWYamide in the holothurian nervous system and its effects on muscular contraction
- Masahide Inoue1,
- RÏdiger Birenheide1,
- Osamu Koizumi2,
- Yoshitaka Kobayakawa3,
- Yojiro Muneoka4 and
- Tatsuo Motokawa1*
- 1 Basic Biology, Faculty of Bioscience and Biotechnology Tokyo Institute ofTechnology, Meguro–ku,Tokyo 152– 8551Japan
- 2 Neuroscience Laboratory, Faculty of Human Environmental Science FukuokaWomen's University, Fukuoka 813– 8529Japan
- 3 Biological Laboratory, Faculty of Science Kyushu University, Fukuoka 810– 8560Japan
- 4 Faculty of Integrated Arts and Sciences Hiroshima University, Higashi–Hiroshima 739– 8526Japan
- Author for correspondence (tmotokaw{at}bio.titech.ac.jp)
Abstract
NGIWYamide is a peptide recently isolated from the sea cucumber Apostichopus japonicus. It stiffens the connective tissue of the holothurian body wall. Localization of NGIWYamide was investigated by immunohistochemical staining with antiserum raised against NGIWYamide. In holothurian nervous systems NGIWYamide–like immunoreactivity (NGIWYa–LI) was observed in the hyponeural and ectoneural regions of the radial nerve cord, as well as in the circumoral nerve ring, podial nerves, tentacular nerves, the basiepithelial nerve plexus of the intestine and in cellular processes running through the body wall dermis. Labelled nerve fibres from the hyponeural part of the radial nerve running towards the circular muscle and from the podial nerve into the body wall dermis suggest that NGIWYamide controls both muscle and connective tissue. We examined the effect on muscle activity of the sea cucumber. NGIWYamide (10–7 to 10–4 M) caused contraction of the longitudinal body wall muscle. Tentacles showed contraction only at a higher dose (10–4 M). NGIWYamide (10–4 M) inhibited spontaneous contraction of the intestine.
Social Networking