Age- and sex-related changes in the severity of physical and psychological dependence in morphine-dependent rats.

Gender- and age-dependent effects on the severity of morphine dependence are still controversial. The aim of this study was to investigate the effects of age and sex on the severity of physical and psychological dependence in morphine-dependent rats. The adult/aged male and female Wistar rats were chronically treated with bi-daily doses (10 mg/kg, at 12 h intervals) of morphine for 14 days.

Effect of enriched environment during adolescence on spatial learning and memory, and voluntary consumption of morphine in maternally separated rats in adulthood.

This study was designed to examine the effect of environmental enrichment (EE) during adolescence on spatial learning and memory and voluntary morphine consumption in maternally separated (MS) male and female rats in adulthood. Male Wistar rats were allowed to mate with female virgin Wistar rats. Pups were separated from the dams daily for 180 min during postnatal days 2-14.