Effects of naltrexone in postnatal rats on the recovery of disturbed brain and lymphatic tissues after X-irradiation or ethylnitrosourea treatment in utero
The role of endogenous opioid systems in preweaning development after intrauterine exposure to X-irradiation or ethylnitrosourea (ENU) was explored in rats using naltrexone, a potent antagonist of beta-endorphin. After daily s.c. injections of 50 mg/kg naltrexone only the prenatally untreated controls had body weights increased by 11% from control level on day 28 (weaning). In the X-irradiated as well as the ENU-treated pups no significant effects of naltrexone on body weight gain were observed. However, brain weight increased in all animals under the influence of naltrexone, irrespective of prenatal treatment or the severity of brain lesions: 9.5% above control values in untreated offspring and 14% after X-irradiation (1 Gy) on gestation day 14. The brain weight of ENU-treated rats (50 mg/kg on gest. day 14) was 13% higher after postnatal naltrexone application than that of their postnatally untreated counterparts. ENU (80 mg/kg) effects on the brain when given on gestation day 18 were ameliorated to 9.2% by naltrexone in the weaning period. Naltrexone significantly increased the thymus weight in controls. Prenatally treated animals also showed an increased thymus weight at weaning, presumably due to compensatory growth. In these cases naltrexone revealed a suppressive effect on the thymus, whereas spleen weight was apparently not influenced by naltrexone treatment. These results provide compelling evidence that endogenous opioid systems play a crucial role not only in normal development, but also in reparative growth events of the brain after prenatal injuries. The thymus, predominantly containing T-lymphocytes, seems to represent another sensitive system which is regulated under the influence of opioids.
- Research Organization:
- Gesellschaft fuer Strahlen- und Umweltforschung, m.b.H. Muenchen, Abteilung Nuklearbiologie, Neuherberg, West Germany
- OSTI ID:
- 6515600
- Journal Information:
- Res. Commun. Chem. Pathol. Pharmacol.; (United States), Vol. 1
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
NARCOTICS
BIOLOGICAL EFFECTS
RADIOSENSITIVITY EFFECTS
NITROSOUREAS
TOXICITY
AGING
BRAIN
PREGNANCY
PRENATAL EXPOSURE
RATS
SPLEEN
SUBCUTANEOUS INJECTION
THYMUS
X RADIATION
ANIMALS
BODY
CENTRAL NERVOUS SYSTEM
CENTRAL NERVOUS SYSTEM DEPRESSANTS
DRUGS
ELECTROMAGNETIC RADIATION
INJECTION
INTAKE
IONIZING RADIATIONS
LYMPHATIC SYSTEM
MAMMALS
NERVOUS SYSTEM
NITROSO COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC NITROGEN COMPOUNDS
ORGANS
RADIATIONS
RODENTS
VERTEBRATES
560152* - Radiation Effects on Animals- Animals
560300 - Chemicals Metabolism & Toxicology