Low‐Level Radiofrequency Exposure Induces Vasoconstriction in Rats

Abstract

Recent studies have revealed that rodents' physiological responses to low intensity radiofrequency electromagnetic fields (RF) were similar to thermoregulatory responses to cold conditions. The primary autonomic response to cold exposure is peripheral vasoconstriction that allows rodents to reduce heat loss and maintain a relatively constant internal body temperature. In the present study, we investigated the effects of 900 MHz RF at a low level (SAR of 0.35 W.kg -1 ) on tail skin temperature (T tail ) in rats. We showed that rats exposed to RF had lower T tail than control rats at ambient temperatures between 27 and 28 °C, suggesting that RF could induce a noticeable degree of vasoconstriction under mild-warm ambient temperatures. This difference in T tail was suppressed after the intraperitoneal injection of a vasodilator, an α-adrenergic antagonist, confirming the hypothesis of the vasoconstriction in exposed rats. Moreover, like a response to cold stimuli, RF exposure led to a higher plasma concentration of important factors involved in response to cold: noradrenaline, a neurotransmitter responsible for vasoconstriction and thermogenesis, and fatty acids, markers of activated thermogenesis. Taken together, these findings indicate that low-intensity RF levels triggered some key physiological events usually associated with responses to cold in rats.

Strategies for Hypothermia Compensation in Altricial and Precocial Newborn Mammals and Their Monitoring by Infrared Thermography

“…When exposed to a cold stimulus, the cold-sensitive neurons located in the POA and the activation of the HPA axis induce the secretion of catecholamines (epinephrine and NE) and other neurotransmitters such as neuropeptide and ATP [ 35 ]. Consequently, they activate receptors in the blood vessels to produce vasoconstriction [ 125 , 126 ] to divert blood flow from the limbs or peripheral structures to vital organs [ 127 , 128 , 129 ]. Solomon et al [ 130 ] demonstrated this in four Long Evans rats ( Rattus norvegicus ) subjected to motility frustration (e.g., not being able to use an activity wheel).…”

Vitality in Newborn Farm Animals: Adverse Factors, Physiological Responses, Pharmacological Therapies, and Physical Methods to Increase Neonate Vigor

“…In the case of cold stimuli, the participation of the HPA axis, the secretion of catecholamines (epinephrine and norepinephrine), and their action on the receptors located in the blood vessels generate a vasoconstriction effect [122,123]. The objective of vasoconstriction is to redirect the blood flow of the extremities or peripheral structures toward internal organs and vital centers, limiting heat loss through the skin [124][125][126].…”