Evidence of a circadiam clock mechanism was found in the cave crayfish, Orconectes pellucidus, even though it is blind and has been isolated from daiIy cycles for at least 25,000 generations. Five of seven crayfish tested under cave conditions of continuous darkness and 13°C showed apparent rhythms
The circadian system of crayfish: A developmental approach
✍ Scribed by María Luisa Fanjul-Moles; Julio Prieto-Sagredo
- Publisher
- John Wiley and Sons
- Year
- 2003
- Tongue
- English
- Weight
- 427 KB
- Volume
- 60
- Category
- Article
- ISSN
- 1059-910X
No coin nor oath required. For personal study only.
✦ Synopsis
Abstract
Adult crayfish exhibit a variety of overt circadian rhythms. However, the physiological mechanisms underlying the overt rhythms are controversial. Research has centered on two overt rhythms: the motor activity and the retinal sensitivity rhythms of the genus Procambarus. The present work reviews various studies undertaken to localize pacemakers and mechanisms of entrainment responsible for these two rhythms in adult organisms of this crustacean decapod. It also describes an ontogenetic approach to the problem by means of behavioral, electrophysiological, and neurochemical experiments. The results of this approach confirm previous models proposed for adult crayfish, based on a number of circadian pacemakers distributed in the central nervous system. However, the coupling of rhythmicity between these independent oscillators might be complex and dependent on the interaction between serotonin (5‐HT), light, and the crustacean hyperglycemic hormone (CHH). The latter compound has, up until now, not been considered as an agent in the genesis and synchronization of the retinal sensitivity rhythm. Microsc. Res. Tech. 60:291–301, 2003. © 2003 Wiley‐Liss, Inc.
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