Ionizing Radiation Decreases Veratridine-Stimulated Uptake of Sodium in Rat Brain Synaptosomes

Wixon, Henry N.; Hunt, Walter A.

doi:10.1126/science.6302846

Cited by 13 publications

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“…The results of the present study confirm and extend our earlier observation that ionizing radiation reduced the veratridine-stimulated uptake of 22Na+ by rat brain synaptosomes (Wixon and Hunt, 1983). In addition, we determined that high-energy electrons and y radiation were equally effective in reducing veratridine-stimulated 22Na+ uptake.…”

Section: Discussionsupporting

confidence: 90%

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Ionizing Radiation Alters the Properties of Sodium Channels in Rat Brain Synaptosomes

Mullin¹,

Hunt²,

Harris

1986

Journal of Neurochemistry

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The effect of ionizing radiation on neuronal membrane function was assessed by measurement of neurotoxin-stimulated 22Na+ uptake by rat brain synaptosomes. High-energy electrons and y photons were equally effective in reducing the maximal uptake of 22Na+ with no significant change in the affinity of veratridine for its binding site in the channel. Ionizing radiation reduced the veratridine-stimulated uptake at the earliest times measured (3 and 5 s), when the rate of uptake was greatest. Batrachotoxin-stimulated 22Na+ uptake was less sensitive to inhibition by radiation. The binding of [3H]saxitoxin to its receptor in the sodium channel was unaffected by exposure to ionizing radiation. The effect of ionizing radiation on the lipid order of rat brain synaptic plasma membranes was measured by the fluores-cence polarization of the molecular probes 1,6-diphenyl-1,3,5-hexatriene and 1 -[4-(trimethylammonium)phenyl]-6-phenyl-l,3,5-hexatriene. A dose of radiation that reduced the veratridine-stimulated uptake of Z2Na+ had no effect on the fluorescence polarization of either probe. These results demonstrate an inhibitory effect of ionizing radiation on the voltage-sensitive sodium channels in rat brain synaptosomes. This effect of radiation is not dependent on changes in the order of membrane lipids. Key Words: Ionizing radiation-Sodium channels-Membrane fluidity-Fluorescent probes-Neuronal membranes. Mullin M. J. et al. Ionizing radiation alters the properties of sodium channels in rat brain synaptosomes.

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Section: Discussionsupporting

confidence: 90%

“…In addition, nonspecific sodium uptake in the presence of veratridine and TTX and the uptake in the absence of any added toxins were unaffected by ionizing radiation (data not shown). These findings are in agreement with previous work on ion channels in our laboratory (Wixon and Hunt, 1983).…”

Section: Ion Flux Studiessupporting

confidence: 94%