Highly aggressive behavior induced by social stress is associated to reduced cytochrome c oxidase activity in mice brain cortex

Violence and aggression represent severe social problems, with profound impacts on public health. Despite the development of experimental models to study aggressive behavior is highly appreciated, the underlying mechanisms remain poorly understood. Given the key contribution of mitochondria to central nervous system bioenergetics, we hypothesized that mitochondrial function in brain would be altered by social stress. Using a model of spontaneous aggression, we investigated here the effects of social stress on brain mitochondrial function in prefrontal cortex of Swiss mice. Animals were categorized as highly aggressive, subordinate and non-aggressive (harmonic) after stress induced by regrouping and compared them with non-regrouped animals. Despite social stress did not affect brain cortex oxygen consumption rates and NADH:cytochrome c oxidoreductase activity, cytochrome c oxidase expression and activity were significantly lower in highly aggressive animals compared to non-regrouped ones. These changes were not observed in ATP synthase and adenine nucleotide translocator content suggesting a selective effect of social stress on cytochrome c oxidase. Therefore, aggressive behavior generated upon social stress associates to selective reduction in cytochrome c oxidase activity, with potential detrimental effects on brain bioenergetics and function.

Binding of Sulpiride to Seric Albumins

The aim of this work was to study the interaction of sulpiride with human serum albumin (HSA) and bovine serum albumin (BSA) through the fluorescence quenching technique. As sulpiride molecules emit fluorescence, we have developed a simple mathematical model to discriminate the quencher fluorescence from the albumin fluorescence in the solution where they interact. Sulpiride is an antipsychotic used in the treatment of several psychiatric disorders. We selectively excited the fluorescence of tryptophan residues with 290 nm wavelength and observed the quenching by titrating HSA and BSA solutions with sulpiride. Stern-Volmer graphs were plotted and quenching constants were estimated. Results showed that sulpiride form complexes with both albumins. Estimated association constants for the interaction sulpiride–HSA were 2.20 (±0.08) × 10⁴ M⁻¹, at 37 °C, and 5.46 (±0.20) × 10⁴ M⁻¹, at 25 °C. Those for the interaction sulpiride-BSA are 0.44 (±0.01) × 10⁴ M⁻¹, at 37 °C and 2.17 (±0.04) × 10⁴ M⁻¹, at 25 °C. The quenching intensity of BSA, which contains two tryptophan residues in the peptide chain, was found to be higher than that of HSA, what suggests that the primary binding site for sulpiride in albumin should be located next to the sub domain IB of the protein structure.

Use of haloperidol and risperidone in highly aggressive Swiss Webster mice by applying the model of spontaneous aggression (MSA)

Aggression is defined as the act in which an individual intentionally harms or injures another of their own species. Antipsychotics are a form of treatment used in psychiatric routine. They have been used for decades in treatment of patients with aggressive behavior. Haloperidol and risperidone promote the control of psychiatric symptoms, through their respective mechanisms of action. Experimental models are obtained by behavioral, genetic, and pharmacological manipulations, and use a reduced number of animals. In this context, we applied the model of spontaneous aggression (MSA), originating the presence of highly aggressive mice (AgR) when reassembled in adulthood. We administered haloperidol and risperidone in escalating doses, for ten consecutive days. Using positive and negative control groups, we evaluated the effectiveness of these drugs and the reversal of the aggressive behavior, performing the tail suspension test (TST) and open field test (OFT) on 10th day of treatment and 10 days after its discontinuation. The results showed that both antipsychotic drugs were effective in AgR and reversed the aggressive phenotype, reducing the number of attacks by AgR and the extent of lesions in the subordinate mice (AgD) exposed to the pattern of aggressive behavior (PAB) of the aggressors. This conclusion is based on the reduction in the animals' motor and exploratory activity, and on the reversal of patterns of aggressive behavior. The association between the MSA and experiments with other therapeutic protocols and different antipsychotics can be an important methodology in the study of aggressive behavior in psychiatric patients.