Effects of oxytocin on methamphetamine-seeking exacerbated by predator odor pre-exposure in rats.

Rationale: The endogenous oxytocin system has emerged as an inhibitor of drug-seeking and stress in preclinical models.

Objectives: The goal of this study was to examine whether systemic oxytocin administration attenuated methamphetamine (METH)-seeking in rats pre-exposed to a predator odor threat.

Methods: In Experiment 1, rats were exposed for 5 days to the predator odor, 2,5-dihydro-2,4,5-trimethylthiazoline (TMT), or saline before METH self-administration began.

Sirtuin activity in dentate gyrus contributes to chronic stress-induced behavior and extracellular signal-regulated protein kinases 1 and 2 cascade changes in the hippocampus.

Background: Exposure to chronic stress produces negative effects on mood and hippocampus-dependent memory formation. Alterations in signaling cascades and histone acetylation present a mechanism of modulation of transcription that may underlie stress-dependent processes in the hippocampus critical to learning and memory and development of depressive behaviors.

Methods: The rat model of chronic variable stress (CVS) was used to investigate the role of changes in protein acetylation and other molecular components of hippocampus-dependent memory formation and anhedonic behavior in response to CVS.

Cage mate separation in pair-housed male rats evokes an acute stress corticosterone response.

Corticosterone (CORT) release from the adrenal glands in response to acutely stressful stimuli is well-characterized, however several non-experimental, environmental stressors can also engender a CORT response. The aim of this study was to investigate an acute activation of the HPA axis in pair-housed animals in response to separation. We observed a rapid significant increase in CORT in the animal remaining in the home cage following cage mate removal, that was not caused by cage opening and transient removal of cage mate.