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.

Epigenetic mechanisms in experience-driven memory formation and behavior.

Epigenetic mechanisms have long been associated with the regulation of gene-expression changes accompanying normal neuronal development and cellular differentiation; however, until recently these mechanisms were believed to be statically quiet in the adult brain. Behavioral neuroscientists have now begun to investigate these epigenetic mechanisms as potential regulators of gene-transcription changes in the CNS subserving synaptic plasticity and long-term memory (LTM) formation. Experimental evidence from learning and memory animal models has demonstrated that active chromatin remodeling occurs in terminally differentiated postmitotic neurons, suggesting that these molecular processes are indeed intimately involved in several stages of LTM formation, including consolidation, reconsolidation and extinction.

Phenotypic flexibility and thermoregulatory behavior in the eastern red-spotted newt (Notophthalmus viridescens viridescens).

Eastern red-spotted newts are ectotherms, aquatic as adults, and active year-round, breeding even during winter under ice. Earlier research, with field-captured newts, showed a correlation between seasonal changes in the activity of some muscle metabolic enzymes and in the behavior of the newts in a thermal gradient. This study was undertaken to further characterize acclimatory responses in the newts in a more controlled laboratory environment.