| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4312991 | Behavioural Brain Research | 2012 | 10 Pages |
In the present study, we determined the effects of environmental enrichment (EE; Kong Toys® and Nestlets®) on sexually diergic HPA axis responses to single-dose nicotine (NIC), single-dose NIC following continuous NIC administration for two weeks, and NIC withdrawal by single-dose mecamylamine (MEC) in male and female rats. Blood sampling occurred before and after MEC and NIC administrations for the determination of adrenocorticotropic hormone (ACTH) and corticosterone (CORT).Supporting and extending our previous findings, EE appeared to produce anxiolytic effects by reducing hormone responses: Male and female rats housed with EE had lower baseline ACTH and significantly lower HPA axis responses to the mild stress of saline (SAL) injection than did those housed without EE. The sexually diergic responses to single dose NIC, continuous NIC, and MEC-induced NIC withdrawal were reduced by EE in many male and female groups. ACTH responses to continuous NIC and MEC-induced NIC withdrawal were blunted to a greater extent in female EE groups than in male EE groups, suggesting that females are more sensitive to the anxiolytic effects of EE. Because EE lowered stress-responsive hormones of the HPA axis in most groups, EE may be a useful intervention for stress reduction in animal models of NIC addiction. As well, the effectiveness of EE in animal studies of NIC withdrawal may enlighten human studies addressing coping styles and tobacco cessation in men and women.
► Environmental enrichment (EE) reduced baseline ACTH and CORT in males and females. ► EE lowered HPA axis responses to SAL, nicotine (NIC), and mecamylamine in most groups. ► Effects of EE were sexually diergic: females were more sensitive to EE than males. ► EE may alter coping during NIC habituation and withdrawal. ► EE may be a useful approach for stress reduction in animal models of NIC addiction.
