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United States Department of Agriculture

Agricultural Research Service

Title: Heavy Particle Irradiation, Neurochemistry and Behavior: Thresholds, Dose-Response Curves and Recovery of Function

Authors
item Rabin, Bernard - UMBC
item Joseph, James
item Shukitt-Hale, Barbara

Submitted to: Advances in Space Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 6, 2004
Publication Date: May 1, 2004
Citation: Rabin, B.M., Joseph, J.A., Shukitt Hale, B. 2004. Heavy particle irradiation, neurochemistry and behavior: thresholds, dose-response curves and recovery of function. Advances in Space Research. 33:1330-1333.

Interpretive Summary: Exposure to heavy particles can affect the functioning of the central nervous system (CNS), particularly one system in the brain called the dopaminergic system. In turn, radiation can induce disruption of a variety of behaviors that are dependent upon this system, including motor behavior (upper body strength), taste aversion learning, and the ability to press a bar to get food reinforcement. Although the relationships between radiation and the effects of exposure depend, to some extent, upon the specific behavioral or brain function parameter being studied, a review of the available research leads to the idea that the endpoints mediated by the CNS have certain characteristics in common. These include: (1) a threshold, below which there is no apparent effect; (2) the lack of a dose-response relationship (i.e., dose does not predict behavior); and (3) no recovery of function, such that the heavy particle-induced behavioral and brain changes are present when tested up to one year following exposure. The current report reviews the data relevant to the degree to which these characteristics are common to brain and behavioral endpoints that are mediated by the effects of exposure to heavy particles on CNS activity.

Technical Abstract: Exposure to heavy particles can affect the functioning of the central nervous system (CNS), particularly the dopaminergic system. In turn, the radiation-induced disruption of dopaminergic function affects a variety of behaviors that are dependent upon the integrity of this system, including motor behavior (upper body strength), amphetamine (dopamine)-mediated taste aversion learning, and operant conditioning (fixed-ratio bar pressing). Although the relationships between heavy particle irradiation and the effects of exposure depend, to some extent, upon the specific behavioral or neurochemical endpoint under consideration, a review of the available research leads to the hypothesis that the endpoints mediated by the CNS have certain characteristics in common. These include: (1) a threshold, below which there is no apparent effect; (2) the lack of a dose-response relationship, or an extremely steep dose-response curve, depending on the particular endpoint; and (3) the absence of recovery of function, such that the heavy particle-induced behavioral and neural changes are present when tested up to one year following exposure. The current report reviews the data relevant to the degree to which these characteristics are common to neurochemical and behavioral endpoints that are mediated by the effects of exposure to heavy particles on CNS activity.

Last Modified: 4/18/2014
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