title: HZE radiation and dopaminergic modification of startle and prepulse inhibition in mice.
abstract: C57BL/6 mice were exposed to 5 Gy (28)Si or (56)Fe particle radiation in order to explore the immediate or short-latency effect of exposure to high energy (HZE) particle radiation on dopaminergic modification of acoustic startle and prepulse inhibition. The radiation is representative of the type which would be encountered as galactic cosmic rays during long-duration space flight. The acoustic startle response was elicited with 120 dB white noise and prepulse inhibition of the startle response was produced with 79 dB and 86 dB stimuli presented with a 125 ms onset asynchrony. Startle reactivity was inhibited by (56)Fe radiation but not by (28)Si particles. Apomorphine (3 mg/kg) produced a general inhibition of startle reactivity while haloperidol (1 mg/kg) facilitated it. Apomorphine disrupted prepulse inhibition, but only in animals which were not exposed to radiation. Both (56)Fe and (28)Si radiation exposure attenuated the disruption of prepulse inhibition induced by apomorphine. In contrast, the facilitation of prepulse inhibition induced by haloperidol was not modified by radiation. These data are consistent with a short-latency disruption of dopaminergic systems by HZE particle radiation. We speculate that this disruption may occur as a restriction in the capacity of the dopaminergic system.
authors.affiliation: NeuroCognition and Brain Studies Section, Department of Psychology, School of Science and Technology, Loma Linda University and Medical Center, CA 92350, USA. phaerich@llu.edu
authors.forename: Paul
authors.initials: P
authors.lastname: Haerich
authors.forename: Gregory A
authors.initials: GA
authors.lastname: Nelson
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Pecaut
mesh_terms: D000161:Acoustic Stimulation / Q000379:methods; D000818:Animals; D001058:Apomorphine / Q000494:pharmacology; D001522:Behavior, Animal / Q000187:drug effects / Q000528:radiation effects; D003359:Cosmic Radiation; D004298:Dopamine / Q000502:physiology*; D018491:Dopamine Agonists / Q000494:pharmacology; D018492:Dopamine Antagonists / Q000494:pharmacology; D004307:Dose-Response Relationship, Radiation; D006220:Haloperidol / Q000494:pharmacology; D007501:Iron; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D009433:Neural Inhibition / Q000187:drug effects / Q000502:physiology / Q000528:radiation effects*; D013216:Reflex, Startle / Q000187:drug effects / Q000528:radiation effects*; D012825:Silicon
chemical_list: D018491:Dopamine Agonists; D018492:Dopamine Antagonists; D007501:Iron; D006220:Haloperidol; D001058:Apomorphine; D004298:Dopamine; D012825:Silicon