Send to

Choose Destination
Behav Neurosci. 1989 Dec;103(6):1168-75.

Opioidlike effects of intraoral infusions of corn oil and polycose on stress reactions in 10-day-old rats.

Author information

Department of Psychology, Johns Hopkins University, Baltimore, Maryland 21218.


The effects of intraoral infusions of corn oil and the polysaccharide Polycose on behavioral reactions to pain and to social isolation were studied in 10-day-old albino rat pups. Both substances significantly increased paw-lift latencies (a measure of pain response) and reduced the number of ultrasonic vocalizations (a measure of isolation distress). Moreover, elevated pain thresholds were normalized by naltrexone (0.25 mg/kg) pretreatment, and the quieting of vocalizations was abolished by pretreatment. These findings indicate an interaction between ingestion, pain, and distress systems in neonatal rats and suggest that fats and polysaccharides influence these systems via endogenous opioids.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for American Psychological Association
Loading ...
Support Center