Multiple power-density windows and their possible origin
We have previously reported that in vitro exposure of chick forebrain tissue to 50-MHz radiofrequency (RF) electromagnetic radiation, amplitude modulated (AM) at 16 Hz, would enhance the efflux of calcium ions within only two power-density ranges: one from 1.44 to 1.67 mW/cm2, and the other including 3.64 mW/cm2. No effect on efflux occurred at 0.37, 0.72, 2.17, and 4.32 mW/cm2. We confirmed and extended these results by testing at another set of power densities, which included the range of the previous study. Forebrain tissue from 1-7-day-old chickens was labeled in vitro with radioactive calcium ions (30 min, at 37 degrees C), rinsed, placed in a physiological salt solution, and then exposed for 20 min to 50-MHz radiation, AM at 16 Hz, in a transverse electric and magnetic field (TEM) cell maintained at 37 degrees C. The solution was then assayed for radioactive calcium activity. A power-density series was tested. An enhanced efflux of calcium ions was found at 1.75, 3.85, 5.57, 6.82, 7.65, 7.77, and 8.82 mW/cm2; no change was observed at 0.75, 2.30, 4.50, 5.85, 7.08, 8.19, 8.66, 10.6, and 14.7 mW/cm2. Power density is converted to specific absorption rate (SAR) by 0.36 mW/kg per mW/cm2. Even the highest SAR tested (0.005 W/kg) is much too low to result in generalized heating of the sample and thus to be the underlying cause of the enhanced response. A hypothetical mechanism is proposed involving dynamic systems that may account for the power-density dependency as well as for part of the frequency dependency observed with both modulated RF radiation and extremely-low-frequency (ELF) fields.70 references.
- Research Organization:
- Environmental Protection Agency, Research Triangle Park, NC (USA)
- OSTI ID:
- 6070100
- Journal Information:
- Bioelectromagnetics (N.Y.); (United States), Vol. 10:2
- Country of Publication:
- United States
- Language:
- English
Similar Records
Terrestrial Trunked Radio (TETRA) exposure of neuronal in vitro networks
Radiofrequency radiation-induced calcium ion efflux enhancement from human and other neuroblastoma cells in culture
Related Subjects
59 BASIC BIOLOGICAL SCIENCES
BRAIN
SENSITIVITY
CALCIUM COMPOUNDS
SECRETION
ELECTROMAGNETIC RADIATION
BIOLOGICAL EFFECTS
ANIMAL TISSUES
CALCIUM ISOTOPES
CHICKENS
DOSE-RESPONSE RELATIONSHIPS
IN VITRO
MHZ RANGE 01-100
REVIEWS
TRACER TECHNIQUES
ALKALINE EARTH ISOTOPES
ALKALINE EARTH METAL COMPOUNDS
ANIMALS
BIRDS
BODY
CENTRAL NERVOUS SYSTEM
DOCUMENT TYPES
FOWL
FREQUENCY RANGE
ISOTOPE APPLICATIONS
ISOTOPES
MHZ RANGE
NERVOUS SYSTEM
ORGANS
RADIATIONS
TISSUES
VERTEBRATES
560400* - Other Environmental Pollutant Effects
550201 - Biochemistry- Tracer Techniques