Association of 24h maternal deprivation with a saline injection in the neonatal period alters adult stress response and brain monoamines in a sex-dependent fashion

Author(s)

Cabbia, Rafael ^[1] ; Consoli, Amanda ^[1] ; Suchecki, Deborah ^[1]

Affiliation

^[1] Univ Fed Sao Paulo, Escola Paulista Med, Dept Psicobiol, Sao Paulo - Brazil

• Document type: Journal article
• Source: STRESS-THE INTERNATIONAL JOURNAL ON THE BIOLOGY OF STRESS; v. 21, n. 4, p. 333-346, 2018.
• Web of Science Citations: 4

Abstract

Maternal deprivation (MD) disinhibits the adrenal glands, rendering them responsive to various stressors, including saline injection, and this increased corticosterone (CORT) response can last for as long as 2h. In the present study, we tested the hypothesis that association of MD on day 11 with a saline injection would alter emotional behavior, CORT response, and brain monoamine levels, in male and female adult rats. Rats were submitted to the novelty suppressed feeding (NSF), the sucrose negative contrast test (SNCT), social investigation test (SIT), and the elevated plus maze (EPM). One quarter of each group was not tested (providing basal values of CORT and brain monoamines) and the remainder was decapitated 15, 45, or 75min after the EPM, to assess CORT reactivity. Monoamine levels were determined in the hypothalamus (HPT), frontal cortex (FC), amygdala (AMY), ventral, and dorsal hippocampus (vHPC, dHPC, respectively). MD reduced food intake, in the home-cage, and latency to eat in the NSF in both sexes; females explored less the target animal in the SIT and explored more the open arms of the EPM than males; the CORT response to the EPM was greater in maternally-deprived males and females than in their control counterparts, and this response was further elevated in maternally-deprived females injected with saline. Regarding monoamine levels, females were less affected, showing isolated effects of the stressors, while in males, MD increased 5-HT levels in the HPT and decreased this monoamine in the FC, MD associated with saline reduced dopamine levels in all brain regions, except the HPT. MD at 11days did not alter emotional behaviors in adult rats, but had an impact in neurobiological parameters associated with this class of behaviors. The impact of MD associated with saline on dopamine levels suggests that males may be vulnerable to motivation-related disorders. (AU)

• FAPESP's process: 14/22395-0 - Sustained corticosterone secretion on postnatal day 11: behavioral and neurochemical effects in adult female and male rats
• Grantee: Rafael Cabbia
• Support Opportunities: Scholarships in Brazil - Master
• FAPESP's process: 15/26364-4 - Neurobiologic mechanisms involved in the long-term emotional effects of maternal deprivation
• Grantee: Deborah Suchecki
• Support Opportunities: Regular Research Grants