Stimulation of cutaneous mechanoreceptors by 60‐Hz electric fields

Abstract

Chronic exposure of animals to 60-Hz electric fields is known to affect the nervous system in a variety of subtle ways. The mechanism whereby these effects are produced remains unknown. One hypothesis is that the effects are a result of direct interaction between neuronal membranes and induced currents. Alternatively, the effects could be produced indirectly, as a result of sensory stimulation and the resulting low-level stress. To test these hypotheses, a system was developed to expose the surface of an anesthetized cat's paw to surface electric fields up to 600 kV/m while simultaneously measuring, in dorsal root fibers, afferent nerve impulses originating from various receptor types in the exposed paw. Of the 245 receptor units tested, comprising ten cutaneous receptor types, ten responded to the electric field with an increase in firing rate. The most sensitive receptor type was the rapidly adapting field receptor (RAF); eight of 20 (40%) were sensitive to the electric field, with thresholds as low as 160 kV/m. One of 35 rapidly adapting high-frequency receptors and one of 22 type T hair-follicle receptors were also sensitive to the electric field. Follow-up tests on the RAF receptors showed that hair removal reduced but did not eliminate the electric field sensitivity, suggesting that at least one other mechanism was involved in addition to stimulation via hair movement. The most likely mechanism is field-induced vibrations of the skin, since a further reduction in firing rate occurred following application of mineral oil to the depilated paw. Direct interaction with neuronal membranes is not supported by our evidence.

Perception of local DC and AC electric fields in humans

“…At present, we cannot exclude the possibility that some other receptor type, innervating glabrous skin, may also be activated by AC electric fields. Electrophysiological studies [Weigel et al, 1987] indicate that AC electric fields activate RAF receptors in the cat. These receptors are not associated with hair, but respond to the skin displacement induced directly or indirectly by hair displacement.…”

“…Third, subjects in several studies (AC and DC) referred to a sense of hair movement during field presentation [Cabanes and Gary, 1981;Kato et al, 1989;Blondin et al, 1996]. Finally, Weigel et al [1987] showed that rapidly adapting field receptors [RAF, according to the classification of Burgess et al, 1968] innervating the hairy skin of the cat's paw are activated by AC electric fields. In contrast, they found that only 1/35 presumed Pacinian afferents and 1/22 hair follicle afferents were sensitive to AC fields.…”

Effect of Electric Field in Conditioned Aversion Response

“…The mechanism(s) of the response to EF have been suggested that either the EFinduced electric current or the perception of the EF through the skin surface act as a trigger on cellular, hormonal or behavioral responses [3,[5][6][7][8]. It is essential to determine whether rat did percept the EF used in previous studies, even though it is easily expectable that strong intensity of EF is sensed by animals [9][10][11].…”

60 Hz electric field upregulates cytosolic Ca2+ level in mouse splenocytes stimulated by lectin

“…*Significant difference between two groups (Paired t-test: P < .05, n ¼ 4). current and indirect stimulation by the perception of extremely low frequency (ELF) field on the body surface have been proposed as possible triggers of the effect of ELF EMF on a living body [Weigel et al, 1987;Kato et al, 1989]. While, magnetic field can generally penetrate the cell membrane, the ELF EF cannot because of the presence of the lipid bilayer (plasma membrane) that functions as an electrical insulator [Poo, 1981;Lee et al, 1993].…”