Bystander effects of ionizing radiation can be modulated by signaling amines
- Department of Medical Physics and Applied Radiation Sciences, Juravinski Cancer Centre, McMaster University, Hamilton, Ont. (Canada)
Actual risk and risk management of exposure to ionizing radiation are among the most controversial areas in environmental health protection. Recent developments in radiobiology especially characterization of bystander effects have called into question established dogmas and are thought to cast doubt on the scientific basis of the risk assessment framework, leading to uncertainty for regulators and concern among affected populations. In this paper we test the hypothesis that small signaling molecules widely used throughout the animal kingdom for signaling stress or environmental change, such as 5-Hydroxytryptamine (5-HT, serotonin), L-DOPA, glycine or nicotine are involved in bystander signaling processes following ionizing radiation exposure. We report data which suggest that nano to micromolar concentrations of these agents can modulate bystander-induced cell death. Depletion of 5-HT present in tissue culture medium, occurred following irradiation of cells. This suggested that 5-HT might be bound by membrane receptors after irradiation. Expression of 5-HT type 3 receptors which are Ca{sup 2+} ion channels was confirmed in the cells using immunocytochemistry and receptor expression could be increased using radiation or 5-HT exposure. Zofran and Kitryl, inhibitors of 5-HT type 3 receptors, and reserpine a generic serotonin antagonist block the bystander effect induced by radiation or by serotonin. The results may be important for the mechanistic understanding of how low doses of radiation interact with cells to produce biological effects.
- OSTI ID:
- 21077739
- Journal Information:
- Environmental Research, Vol. 105, Issue 2; Other Information: DOI: 10.1016/j.envres.2006.12.003; PII: S0013-9351(06)00261-1; Copyright (c) 2006 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); ISSN 0013-9351
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
ANIMALS
APOPTOSIS
BIOLOGICAL RADIATION EFFECTS
CALCIUM IONS
DOPA
GLYCINE
HEALTH HAZARDS
IONIZING RADIATIONS
IRRADIATION
NICOTINE
RADIATION PROTECTION
RADIOBIOLOGY
RECEPTORS
RESERPINE
RISK ASSESSMENT
SEROTONIN
TISSUE CULTURES