Sex differences in contextual fear conditioning are associated with differential ventral hippocampal extracellular signal-regulated kinase activation. Neuroscience 2009 Mar 17;159(2):451-67
Date
01/28/2009Pubmed ID
19171181DOI
10.1016/j.neuroscience.2009.01.009Scopus ID
2-s2.0-60849094364 (requires institutional sign-in at Scopus site) 71 CitationsAbstract
Although sex differences have been reported in hippocampal-dependent learning and memory, including contextual fear memories, the underlying molecular mechanisms contributing to such differences are not well understood. The present study examined the extent to which sex differences in contextual fear conditioning are related to differential activation of the extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK), a protein kinase critically involved in memory formation. We first show that male rats exhibit more long-term retention of contextual fear conditioning than female rats. During a tone test, females spent more time freezing than males, although both sexes exhibited robust retention of auditory fear learning. Using Western blot analysis, we then show that phosphorylated ERK levels in ventral, but not dorsal, hippocampus are higher in males than females, relative to same-sex controls, 60 minutes after fear conditioning. Post-conditioning increases in ERK activation were observed in the amygdala in both males and females, suggesting a selective effect of sex on hippocampal ERK activation. Together, these findings suggest that differential activation of the ERK signal transduction pathway in male and female rats, particularly in the ventral hippocampus, is associated with sex differences in contextual fear.
Author List
Gresack JE, Schafe GE, Orr PT, Frick KMAuthor
Karyn Frick BA,MA,PhD Professor in the Psychology department at University of Wisconsin - MilwaukeeMESH terms used to index this publication - Major topics in bold
Acoustic StimulationAmygdala
Animals
Extracellular Signal-Regulated MAP Kinases
Fear
Female
Freezing Reaction, Cataleptic
Gene Expression Regulation, Enzymologic
Hippocampus
Male
Rats
Rats, Long-Evans
Sex Characteristics
Signal Transduction
Time Factors
