Selection for stress-induced analgesia affects the mouse hippocampal transcriptome

Area of Science:

• Neuroscience
• Genetics
• Behavioral Biology

Background:

• Individual differences in stress responsiveness, including pain sensitivity and stress-induced analgesia (SIA), are influenced by genetics and the hippocampus.
• Previous research suggests a role for the hippocampus in mediating SIA, but the specific genetic underpinnings remain incompletely understood.

Purpose of the Study:

• To investigate differences in constitutive gene expression within the hippocampus of mouse lines selectively bred for high (HA) and low (LA) swim SIA.
• To identify specific genes and pathways affected by selective breeding for SIA and explore their potential role in stress responsiveness.

Main Methods:

• Comparative analysis of hippocampal gene expression in non-stressed HA and LA mice using transcriptomic profiling.
• Identification of genes with at least 1.5-fold expression differences between the HA and LA lines.

Main Results:

• Significant differences in the expression of 205 genes were observed in the hippocampus between HA and LA mice.
• Genes related to calcium signaling were upregulated in LA mice, while HA mice showed upregulation of genes involved in transcription factors and neurotensin/GABA receptors.
• Differentially expressed genes were enriched in functional networks including metabolism, gene expression regulation, and molecular transport.

Conclusions:

• Selective breeding for a specific stress response trait (swim SIA) profoundly impacts the constitutive hippocampal transcriptome.
• The identified gene expression differences suggest novel, potentially non-opioid, mechanisms underlying SIA in HA mice.
• Constitutive hippocampal gene expression patterns may be closely associated with individual differences in stress responsiveness.