Distribution and rhythmic locomotor patterns of estuarine and open-shore populations of Carcinus maenas

Author(s):  
I. J. McGaw ◽  
E. Naylor

Populations of Carcinus maenas (Crustacea: Decapoda) from an estuary and from the open shore were compared for salinity tolerance and rhythmic locomotor activity. Estuarine crabs were shown to be predominantly green; red and orange individuals were rare within the estuary in contrast to the open shore. Red crabs were less able to tolerate prolonged exposure to low salinity than green crabs. Spontaneous circatidal rhythms of locomotor activity were similar in red and green forms, but red crabs from the open shore reacted earlier, and were more active upon salinity reduction, than green crabs from the estuary which also showed rapid habituation to episodes of salinity change.

2010 ◽  
Vol 298 (5) ◽  
pp. R1409-R1416 ◽  
Author(s):  
Amy Warner ◽  
Preeti H. Jethwa ◽  
Catherine A. Wyse ◽  
Helen I'Anson ◽  
John M. Brameld ◽  
...  

The objective of this study was to determine whether the previously observed effects of photoperiod on body weight in Siberian hamsters were due to changes in the daily patterns of locomotor activity, energy expenditure, and/or feeding behavior. Adult males were monitored through a seasonal cycle using an automated comprehensive laboratory animal monitoring system (CLAMS). Exposure to a short-day photoperiod (SD; 8:16-h light-dark cycle) induced a significant decline in body weight, and oxygen consumption (V̇o2), carbon dioxide production (V̇co2), and heat production all decreased reaching a nadir by 16 wk of SD. Clear daily rhythms in locomotor activity, V̇o2, and V̇co2 were observed at the start of the study, but these all progressively diminished after prolonged exposure to SD. Rhythms in feeding behavior were also detected initially, reflecting an increase in meal frequency but not duration during the dark phase. This rhythm was lost by 8 wk of SD exposure such that food intake was relatively constant across dark and light phases. After 18 wk in SD, hamsters were transferred to a long-day photoperiod (LD; 16:8-h light-dark cycle), which induced significant weight gain. This was associated with an increase in energy intake within 2 wk, while V̇o2, V̇co2, and heat production all increased back to basal levels. Rhythmicity was reestablished within 4 wk of reexposure to long days. These results demonstrate that photoperiod impacts on body weight via complex changes in locomotor activity, energy expenditure, and feeding behavior, with a striking loss of daily rhythms during SD exposure.


1995 ◽  
Vol 268 (5) ◽  
pp. R1111-R1116 ◽  
Author(s):  
P. Depres-Brummer ◽  
F. Levi ◽  
G. Metzger ◽  
Y. Touitou

In a constant environment, circadian rhythms persist with slightly altered period lengths. Results of studies with continuous light exposure are less clear, because of short exposure durations and single-variable monitoring. This study sought to characterize properties of the oscillator(s) controlling the rat's circadian system by monitoring both body temperature and locomotor activity. We observed that prolonged exposure of male Sprague-Dawley rats to continuous light (LL) systematically induced complete suppression of body temperature and locomotor activity circadian rhythms and their replacement by ultradian rhythms. This was preceded by a transient loss of coupling between both functions. Continuous darkness (DD) restored circadian synchronization of temperature and activity circadian rhythms within 1 wk. The absence of circadian rhythms in LL coincided with a mean sixfold decrease in plasma melatonin and a marked dampening but no abolition of its circadian rhythmicity. Restoration of temperature and activity circadian rhythms in DD was associated with normalization of melatonin rhythm. These results demonstrated a transient internal desynchronization of two simultaneously monitored functions in the rat and suggested the existence of two or more circadian oscillators. Such a hypothesis was further strengthened by the observation of a circadian rhythm in melatonin, despite complete suppression of body temperature and locomotor activity rhythms. This rat model should be useful for investigating the physiology of the circadian timing system as well as to identify agents and schedules having specific pharmacological actions on this system.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Ovidiu-Dumitru Ilie ◽  
Emanuela Paduraru ◽  
Madalina-Andreea Robea ◽  
Ioana-Miruna Balmus ◽  
Roxana Jijie ◽  
...  

Background. As every organ within the body, the brain is also extremely susceptible to a plethora of noxious agents that change its chemistry. One component frequently found in current products against harmful species to crops is rotenone whose effect under prolonged exposure has been demonstrated to cause neurodegenerative disorders such as Parkinson’s disease. The latest reports have indeed revealed that rotenone promotes Parkinson’s in humans, but studies aiming to show congruent effects in zebrafish (Danio rerio) are lacking. Material and Methods. In this context, the aim of the present study was to demonstrate how chronic administration of rotenone for 3 weeks impairs the locomotor activity and sociability and induces oxidative stress in zebrafish. Results. There were no statistically significant differences following the analysis of their social interaction and locomotor tests ( p > 0.05 ). However, several exceptions have been noted in the control, rotenone, and probiotics groups when we compared their locomotor activity during the pretreatment and treatment interval ( p < 0.05 ). We further assessed the role of rotenone in disturbing the detoxifying system as represented by three enzymes known as superoxide dismutase (SOD), glutathione peroxidase (GPx), and malondialdehyde (MDA). Despite the fact that there were no statistically significant changes within SOD and GPx levels between the control group and rotenone, probiotics, and rotenone + probiotics ( p > 0.05 ), relevant changes have been observed between the analyzed groups ( p < 0.05 and p < 0.005 , respectively). On the other hand, significant differences ( p < 0.05 ) have been observed for MDA when we analyzed the data between the control group and the other three groups. Conclusions. Our results suggest that rotenone can be successfully used to trigger Parkinson’s disease-related symptomatology in zebrafish.


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