Low-temperature exothermic transitions in brain proteome of mice, effect of scopolamine

Differential scanning calorimetry (DSC) has been employed to examine the thermal behavior of brain tissues affected by a drug-induced neurodegenerative disorder. An animal (mouse) model of scopolamine-induced dementia was used. The DSC measurements performed on supernatants of brain tissue homogenates revealed large differences between the heat capacity profiles for healthy animals and for animals with scopolamine-induced dementia. The heat capacity profiles of the supernatants from healthy animals displayed well expressed exothermic transitions peaking in the range 35-45 °C, thus preceding in temperature the endothermic denaturational transitions. No such exothermic transitions were found in other samples from the same animals, e.g., centrifugation sediments of brain homogenates, liver homogenates, blood plasma. Remarkably, the low-temperature exotherms were completely abolished by the scopolamine treatment. The exothermic events may possibly reflect a process of aggregation of specific protein fractions in the brain supernatants. The reported findings may be important for the elucidation of the molecular mechanisms of cognitive impairment.