The Flinders Sensitive Line of rats, a rat model of depression, has elevated brain glucose utilization when compared to normal rats and the Flinders Resistant Line of rats

The Flinders Sensitive Line (FSL) of rats, developed as a line of rats with behavioral supersensitivity to diisopropyl fluorophosphates, a cholinesterase inhibitor, has been used as a rat model of depression. This line has many behavioral and neurochemical similarities to human depression. Because brain regional glucose utilization has been extensively studied in patients with depression with a rather heterogeneous outcome, it became necessary to evaluate this parameter in a well defined and homogeneous animal model. In the present study, the regional glucose utilization measured in thirty-six distinct brain regions and the pineal body was determined in FSL rats and the values were compared to those found in normal Sprague–Dawley (SPD) rats and the Flinders Resistant Line of rats (FRL: animals which have a high resistance to the above noted cholinesterase inhibitor). The measurements were performed by autoradiography with 2-[14C]deoxyglucose (2-DG) as the tracer. SPD and FRL groups consisted of six and FSL had 8 rats. The rats were sacrificed 45 min following the start of the tracer injection. The results showed that the global, and, in many brain areas, regional, glucose utilization is higher in the FSL rats than in the control SPD rats. The synthesis in the FRL rats was very similar to that of the SPD rats, but it was different in many brain regions from the FSL rats. Because the FSL rats have many neurochemical and behavioral differences, in particular, those parameters having lower values, the results presented here suggest that the biochemical processes in the brain of FSL rats occur with lower efficiency than in either the normal SPD rats or FRL rats.