Abstract |
When rats are exposed to a sufficiently large dose of ionizing radiation they exhibit lethargy, hypokinesia, and deficits in performance. These and other behavioral changes parallel those often observed in this species after a large dose of morphine. Since the release of endogenous opiates has been implicated in some stress reactions, we sought to determine if they might play a part in radiogenic behavioral deficits. Rats were trained to criterion on a signaled avoidance task. Some subjects were then implanted with a pellet containing 75 mg of morphine. Other animals received placebo implants. Over a number of days, morphine tolerance was evaluated by measurement of body temperature changes. Prior to 2500 rad 60Co exposure or sham irradiation, morphine (or placebo) pellets were removed. Twenty-four hours later rats were retested to assess their performance on the avoidance task. Morphine-tolerant subjects performed significantly better than the irradiated placebo-implanted group and no differently than morphine-tolerant/ sham-irradiated animals. Morphine tolerance seems to provide a degree of behavioral radiation resistance. These data are consistent with the hypothesis that endogenous opiate hyperexcretion may play some part in the behavioral deficits often observed after irradiation.
|
Authors | G A Mickley, K E Stevens, J M Burrows, G A White, G L Gibbs |
Journal | Radiation research
(Radiat Res)
Vol. 93
Issue 2
Pg. 381-7
(Feb 1983)
ISSN: 0033-7587 [Print] United States |
PMID | 6823519
(Publication Type: Journal Article, Research Support, U.S. Gov't, Non-P.H.S.)
|
Chemical References |
- Drug Implants
- Radiation-Protective Agents
- Morphine
|
Topics |
- Animals
- Behavior, Animal
(drug effects, radiation effects)
- Body Temperature
(drug effects, radiation effects)
- Drug Implants
- Drug Tolerance
- Fever
(chemically induced)
- Male
- Morphine
(administration & dosage, pharmacology)
- Radiation-Protective Agents
(pharmacology)
- Rats
- Rats, Inbred Strains
- Time Factors
|