Sympathetic hyperfunction causes increased sensitivity of the autonomic nervous system to whole-body X irradiation.
Although the etiology of radiation sickness is still unknown, disturbance of the autonomic nervous system is suggested to be a factor. This study was designed to compare the radiosensitivity of spontaneously hypertensive rats possessing sympathetic hyperfunction and control Wistar-Kyoto rats, and to analyze the effects of radiation on the autonomic nervous system in both strains. After a 7.5-Gy dose of whole-body X irradiation, the blood pressure decreased significantly at 8 h and 2 days in the spontaneously hypertensive rats, but not in the Wistar-Kyoto rats. Epinephrine levels in the adrenal gland of spontaneously hypertensive rats decreased at 4, 8 and 24 h, unlike the Wistar-Kyoto rats. Radiation evoked a stronger increase in norepinephrine in the jejunum and colon of spontaneously hypertensive rats than in Wistar-Kyoto rats. Acetylcholine levels in the jejunum of spontaneously hypertensive rats decreased, in contrast to the increase in Wistar-Kyoto rats within 24 h after irradiation. The survival rate of spontaneously hypertensive rats was lower than that of Wistar-Kyoto rats and weight loss, appetite loss and morphological changes in the jejunum were greater in spontaneously hypertensive rats than in Wistar-Kyoto rats after irradiation. These results indicated that X irradiation caused greater activities in autonomic nervous function and severe radiation injury in spontaneously hypertensive rats. Sympathetic hyperfunction may be associated with a higher sensitivity to radiation, including radiation injury and radiation sickness.
Matsuu
Mutsumi
M
Department of Molecular Pathology, Atomic Bomb Disease Institute, Nagasaki University Graduate School of Biomedical Sciences, Nagasaki, Japan. f1173@cc.nagasaki-u.ac.jp
Shichijo
Kazuko
K
Ikeda
Yuji
Y
Ito
Masahiro
M
Naito
Shinji
S
Okaichi
Kumio
K
Nakashima
Masahiro
M
Nakayama
Toshiyuki
T
Sekine
Ichiro
I
D000818:Animals; D001341:Autonomic Nervous System / Q000503:physiopathology / Q000528:radiation effects*; D001342:Autonomic Nervous System Diseases / Q000209:etiology* / Q000503:physiopathology*; D001794:Blood Pressure / Q000528:radiation effects; D001835:Body Weight / Q000528:radiation effects; D006973:Hypertension / Q000150:complications* / Q000503:physiopathology*; D008297:Male; D011829:Radiation Dosage; D011832:Radiation Injuries / Q000209:etiology* / Q000503:physiopathology*; D011836:Radiation Tolerance / Q000528:radiation effects; D051381:Rats; D017208:Rats, Wistar; D016019:Survival Analysis; D014916:Whole-Body Irradiation / Q000009:adverse effects*