scholarly journals Electromyographic (EMG) Study of Cold Shivering in the Chronic Spinal Dog.

1997 ◽  
Vol 47 (1) ◽  
pp. 81-86
Author(s):  
Akira NAITO ◽  
Ying-Jie SUN ◽  
Yasunori YANAGIDAIRA
Keyword(s):  
Cold Shivering

Potentiated muscular thermogenesis in cold-acclimated muscovy duckling

1985 ◽  
Vol 249 (5) ◽  
pp. R533-R538 ◽  
Author(s):  
H. Barre ◽  
A. Geloen ◽  
J. Chatonnet ◽  
A. Dittmar ◽  
J. L. Rouanet
Keyword(s):  
Metabolic Rate ◽  
Muscular Activity ◽  
Threshold Temperature ◽  
Emg Activity ◽  
Nonshivering Thermogenesis ◽  
Brown Adipose ◽  
Lower Critical Temperature ◽  
Cold Shivering ◽  
Two Temperatures ◽  
Extreme Cold

The capacity for nonshivering thermogenesis (NST) was examined in 26- to 27-day cold-acclimated (CA) muscovy ducklings reared for 21 days at 4 degrees C. Metabolic rate and integrated electromyographic (EMG) muscle activity were measured at ambient temperature ranging from -10 to 28 degrees C. Compared with controls reared at 30 degrees C, CA ducklings were more resistant to cold and had higher peak metabolic rate in extreme cold. Shivering threshold temperature of CA ducklings was 14.2 degrees C lower than lower critical temperature, whereas for controls the two temperatures were similar. Thus CA ducklings exhibited an NST in moderate cold. In addition, at temperatures that produced shivering, EMG activity in CA duckling muscle was lesser than that of controls, even at a higher metabolic rate. Because these ducklings are devoid of brown adipose tissue, these results indicated an increased thermogenic efficiency of muscular activity in CA ducklings.

scholarly journals Octopamine drives honeybee thermogenesis

2021 ◽  
Author(s):  
Sinan Kaya-Zeeb ◽  
Lorenz Engelmayer ◽  
Jasmin Bayer ◽  
Heike Bähre ◽  
Roland Seifert ◽  
...  
Keyword(s):  
Selective Pressure ◽  
Cold Climates ◽  
Physiological Plasticity ◽  
Worldwide Distribution ◽  
Environment Adaptation ◽  
Octopamine Receptors ◽  
Cold Shivering ◽  
Flight Muscles ◽  
Necessary And Sufficient ◽  
Shivering Thermogenesis

In times of environmental change species have two options to survive: they either relocate to a new habitat or they adapt to the altered environment. Adaptation requires physiological plasticity and provides a selection benefit. In this regard, the Western honeybee (Apis mellifera) protrudes with its thermoregulatory capabilities, which enables a nearly worldwide distribution. Especially in the cold, shivering thermogenesis enables foraging as well as proper brood development and thus survival. In this study, we present octopamine signaling as a neurochemical prerequisite for honeybee thermogenesis: we were able to induce hypothermia by depleting octopamine in the flight muscles. Additionally, we could restore the ability to increase body temperature by administering octopamine. Thus we conclude, that octopamine is necessary and sufficient for thermogenesis. Moreover, we show that these effects are mediated by β octopamine receptors. The significance of our results is highlighted by the fact the respective receptor genes underlie enormous selective pressure due to adaptation to cold climates. Finally, octopamine signaling in the service of thermogenesis might be a key strategy to survive in a changing environment.

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