Ionizing radiation alters beta-endorphin-like immunoreactivity in brain but not blood.
Previous behavioral and pharmacological studies have implicated endorphins in radiation-induced locomotor hyperactivity of the C57BL/6J mouse. However, the endogenous opiate(s) responsible for this behavioral change have not been identified. The present study measured beta-endorphin-like immunoreactivity (beta-END-LI) in brain, blood, and combined brain and pituitary samples from irradiated and sham-irradiated C57BL/6J mice. After radiation exposure, levels of beta-END-LI decreased significantly in the brain. A similar, but not statistically significant, decline was measured in combined brain and pituitary samples. Concentrations of blood beta-END-LI were not changed by irradiation. These radiogenic changes in beta-END-LI are in some ways similar to those observed after other stresses. However, radiation-induced locomotor hyperactivity may be mediated more by alterations of beta-END-LI in the brain than in the periphery. Other endogenous opiate systems may also contribute to this behavioral change in the C57BL/6J mouse.
D000818:Animals; D001923:Brain Chemistry / Q000528:radiation effects*; D003037:Cobalt Radioisotopes; D004723:Endorphins / Q000032:analysis / Q000097:blood / Q000528:radiation effects*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009043:Motor Activity / Q000528:radiation effects; D010902:Pituitary Gland / Q000032:analysis / Q000528:radiation effects*; D001615:beta-Endorphin
D003037:Cobalt Radioisotopes; D004723:Endorphins; D001615:beta-Endorphin