Specific hippocampal choline decrease in an animal model of depression.

A decreased level of the hippocampal choline signal was found in patients with depression in previous proton magnetic resonance spectroscopy (H-1-MRS) studies. The objective of this study is to compare choline levels before and after the forced swimming test (FST), an animal model of depression typically used for assessing antidepressant activity. H-1-MRS spectra were obtained from both the left and right hippocampus. After the FST, rats showed a significant decrease of the choline/creatine (Cho/Cr, p=0.037) and choline/N-acetylaspartate (Cho/NAA, p=0.048) ratios in the left hippocampus, but not in the right hippocampus. This finding was analogous to results from patients with depression. It suggests that decreased Cho/Cr and Cho/NAA ratios in the left hippocampal regions might be considered to be biomarkers in rats with depression.