We sought to determine whether the fragile X mental retardation gene fmr1 is regulated in long-term potentiation (LTP) and electroconvulsive shock (ECS). In situ hybridization of fmr1 mRNA in hippocampus of rats given LTP in vivo showed no change in fmr1 mRNA levels relative to control. However, ECS induced a selective increase in fmr1 mRNA expression in the dentate gyrus granule cell layer at 6 h post-ECS. The ECS paradigm may unmask relevant activity-dependent regulatory mechanisms that modulate fmr gene transcription in vivo.

A Golgi-stained section of the dentate gyrus, showing the dentate granule cells, is shown in the picture.

References:

Bramham C, Southard T, Sarvey J, Herkenham M, Brady LS. Unilateral LTP triggers bilateral increases in hippocampal neurotrophin and trk receptor mRNA expression in behaving rats: evidence for interhemispheric communication. J Comp Neurol 1996; 368: 371-382.

Valentine, G., Chakravarty, S., Sarvey,, J., Bramham, C., and Herkenham, M., Fragile X (fmr1) mRNA expression is differentially regulated in two adult models of activity-dependent gene expression. Mol. Brain Res., 2000: 75: 337-341.