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Does exposure to a radiofrequency electromagnetic field modify thermal preference in juvenile rats?

Pelletier A, Delanaud S, de Seze R, Bach V, Libert JP, Loos N - PLoS ONE (2014)

Bottom Line: Our results indicated that relative to control group, exposure to RF-EMF at 31°C was associated with a significantly lower tail skin temperature (-1.6°C) which confirmed previous data.The PS did not differ significantly between the two groups.We conclude that RF-EMF exposure induced a shift in thermal preference towards higher temperatures.

View Article: PubMed Central - PubMed

Affiliation: PériTox Laboratory, UMR-I 01 INERIS, Faculty of Medicine, Jules Verne University of Picardy, Amiens, France.

ABSTRACT
Some studies have shown that people living near a mobile phone base station may report sleep disturbances and discomfort. Using a rat model, we have previously shown that chronic exposure to a low-intensity radiofrequency electromagnetic field (RF-EMF) was associated with paradoxical sleep (PS) fragmentation and greater vasomotor tone in the tail. Here, we sought to establish whether sleep disturbances might result from the disturbance of thermoregulatory processes by a RF-EMF. We recorded thermal preference and sleep stage distribution in 18 young male Wistar rats. Nine animals were exposed to a low-intensity RF-EMF (900 MHz, 1 V x m(-1)) for five weeks and nine served as non-exposed controls. Thermal preference was assessed in an experimental chamber comprising three interconnected compartments, in which the air temperatures (Ta) were set to 24°C, 28°C and 31°C. Sleep and tail skin temperature were also recorded. Our results indicated that relative to control group, exposure to RF-EMF at 31°C was associated with a significantly lower tail skin temperature (-1.6°C) which confirmed previous data. During the light period, the exposed group preferred to sleep at Ta = 31°C and the controls preferred Ta = 28°C. The mean sleep duration in exposed group was significantly greater (by 15.5%) than in control group (due in turn to a significantly greater amount of slow wave sleep (SWS, +14.6%). Similarly, frequency of SWS was greater in exposed group (by 4.9 episodes.h-1). The PS did not differ significantly between the two groups. During the dark period, there were no significant intergroup differences. We conclude that RF-EMF exposure induced a shift in thermal preference towards higher temperatures. The shift in preferred temperature might result from a cold thermal sensation. The change in sleep stage distribution may involve signals from thermoreceptors in the skin. Modulation of SWS may be a protective adaptation in response to RF-EMF exposure.

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Thermal preference during the light period (A) and the dark period (B).The mean ± SEM time (as a percentage of all analysis time) of control rats (open columns) and RF-EMF-exposed rats (filled columns) for the three air temperatures values (24°C, 28°C and 31°C). Statistically significant differences are indicated as follows: (*) p<0.05, control group vs. exposed groups; (†) p<0.05 and (††) p<0.01 light period vs. dark period; (b) p<0.05, 24°C vs. 31°C; (c) p<0.05, 28°C vs. 31°C.
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pone-0099007-g003: Thermal preference during the light period (A) and the dark period (B).The mean ± SEM time (as a percentage of all analysis time) of control rats (open columns) and RF-EMF-exposed rats (filled columns) for the three air temperatures values (24°C, 28°C and 31°C). Statistically significant differences are indicated as follows: (*) p<0.05, control group vs. exposed groups; (†) p<0.05 and (††) p<0.01 light period vs. dark period; (b) p<0.05, 24°C vs. 31°C; (c) p<0.05, 28°C vs. 31°C.

Mentions: These observations were confirmed when we considered the mean values of the time spent in each of the three Ta zones (calculated separately for the dark and the light periods; Figure 3). In the light period, the control animals (open columns) spent more time at a Ta of 28°C than at 31°C (38.7±3.7% and 21.5±5.8%, respectively, p = 0.025). In contrast, the rats in the exposed group (filled columns) preferred a Ta of 31°C (42.5±4.8%) to a Ta of 24°C (21.8±4.0%, p = 0.049) or 28°C (25.9±4.2%, p = 0.049). This difference in thermal preference was confirmed when the animals in the exposed group were compared with those in the control group: +21.0% at 31°C (p = 0.015) and −12.8% at 28°C (p = 0.038). During the dark period, the thermal preference was 24°C and did not appear to depend on RF-EMF exposure. For example, both groups of animals spent more time at a Ta of 24°C than at 31°C (43.9±4.0% and 8.8±3.3%, respectively, p = 0.011 for the control group, and 43.9±5.7 and 16.6±4.2, respectively, p = 0.015 for the exposed group). For both groups of animals, the amount of time spent at a Ta of 24°C was greater during the light period than during the dark period (+15.7%, p = 0.049 for the controls and +24.2%, p = 0.008 for the exposed group). The animals in the exposed group spent less time at a Ta of 31°C during the dark period than during the light period (−28.1%, p = 0.008).


Does exposure to a radiofrequency electromagnetic field modify thermal preference in juvenile rats?

Pelletier A, Delanaud S, de Seze R, Bach V, Libert JP, Loos N - PLoS ONE (2014)

Thermal preference during the light period (A) and the dark period (B).The mean ± SEM time (as a percentage of all analysis time) of control rats (open columns) and RF-EMF-exposed rats (filled columns) for the three air temperatures values (24°C, 28°C and 31°C). Statistically significant differences are indicated as follows: (*) p<0.05, control group vs. exposed groups; (†) p<0.05 and (††) p<0.01 light period vs. dark period; (b) p<0.05, 24°C vs. 31°C; (c) p<0.05, 28°C vs. 31°C.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4048227&req=5

pone-0099007-g003: Thermal preference during the light period (A) and the dark period (B).The mean ± SEM time (as a percentage of all analysis time) of control rats (open columns) and RF-EMF-exposed rats (filled columns) for the three air temperatures values (24°C, 28°C and 31°C). Statistically significant differences are indicated as follows: (*) p<0.05, control group vs. exposed groups; (†) p<0.05 and (††) p<0.01 light period vs. dark period; (b) p<0.05, 24°C vs. 31°C; (c) p<0.05, 28°C vs. 31°C.
Mentions: These observations were confirmed when we considered the mean values of the time spent in each of the three Ta zones (calculated separately for the dark and the light periods; Figure 3). In the light period, the control animals (open columns) spent more time at a Ta of 28°C than at 31°C (38.7±3.7% and 21.5±5.8%, respectively, p = 0.025). In contrast, the rats in the exposed group (filled columns) preferred a Ta of 31°C (42.5±4.8%) to a Ta of 24°C (21.8±4.0%, p = 0.049) or 28°C (25.9±4.2%, p = 0.049). This difference in thermal preference was confirmed when the animals in the exposed group were compared with those in the control group: +21.0% at 31°C (p = 0.015) and −12.8% at 28°C (p = 0.038). During the dark period, the thermal preference was 24°C and did not appear to depend on RF-EMF exposure. For example, both groups of animals spent more time at a Ta of 24°C than at 31°C (43.9±4.0% and 8.8±3.3%, respectively, p = 0.011 for the control group, and 43.9±5.7 and 16.6±4.2, respectively, p = 0.015 for the exposed group). For both groups of animals, the amount of time spent at a Ta of 24°C was greater during the light period than during the dark period (+15.7%, p = 0.049 for the controls and +24.2%, p = 0.008 for the exposed group). The animals in the exposed group spent less time at a Ta of 31°C during the dark period than during the light period (−28.1%, p = 0.008).

Bottom Line: Our results indicated that relative to control group, exposure to RF-EMF at 31°C was associated with a significantly lower tail skin temperature (-1.6°C) which confirmed previous data.The PS did not differ significantly between the two groups.We conclude that RF-EMF exposure induced a shift in thermal preference towards higher temperatures.

View Article: PubMed Central - PubMed

Affiliation: PériTox Laboratory, UMR-I 01 INERIS, Faculty of Medicine, Jules Verne University of Picardy, Amiens, France.

ABSTRACT
Some studies have shown that people living near a mobile phone base station may report sleep disturbances and discomfort. Using a rat model, we have previously shown that chronic exposure to a low-intensity radiofrequency electromagnetic field (RF-EMF) was associated with paradoxical sleep (PS) fragmentation and greater vasomotor tone in the tail. Here, we sought to establish whether sleep disturbances might result from the disturbance of thermoregulatory processes by a RF-EMF. We recorded thermal preference and sleep stage distribution in 18 young male Wistar rats. Nine animals were exposed to a low-intensity RF-EMF (900 MHz, 1 V x m(-1)) for five weeks and nine served as non-exposed controls. Thermal preference was assessed in an experimental chamber comprising three interconnected compartments, in which the air temperatures (Ta) were set to 24°C, 28°C and 31°C. Sleep and tail skin temperature were also recorded. Our results indicated that relative to control group, exposure to RF-EMF at 31°C was associated with a significantly lower tail skin temperature (-1.6°C) which confirmed previous data. During the light period, the exposed group preferred to sleep at Ta = 31°C and the controls preferred Ta = 28°C. The mean sleep duration in exposed group was significantly greater (by 15.5%) than in control group (due in turn to a significantly greater amount of slow wave sleep (SWS, +14.6%). Similarly, frequency of SWS was greater in exposed group (by 4.9 episodes.h-1). The PS did not differ significantly between the two groups. During the dark period, there were no significant intergroup differences. We conclude that RF-EMF exposure induced a shift in thermal preference towards higher temperatures. The shift in preferred temperature might result from a cold thermal sensation. The change in sleep stage distribution may involve signals from thermoreceptors in the skin. Modulation of SWS may be a protective adaptation in response to RF-EMF exposure.

Show MeSH
Related in: MedlinePlus