title: Activity of mitochondrial respiratory chain is increased by chronic administration of antidepressants.
abstract: OBJECTIVE
  Depressive disorders, including major depression, are serious and disabling for affected patients. Although the neurobiological understanding of major depressive disorder focuses mainly on the monoamine hypothesis, the exact pathophysiology of depression is not fully understood.
  
  
  METHODS
  Animals received daily intra-peritoneal injections of paroxetine (10 mg/kg), nortriptyline (15 mg/kg) or venlafaxine (10 mg/kg) in 1.0 ml/kg volume for 15 days. Twelve hours after the last injection, the rats were killed by decapitation, where the brain was removed and homogenised. The activities of mitochondrial respiratory chain complexes in different brain structures were measured.
  
  
  RESULTS
  We first verified that chronic administration of paroxetine increased complex I activity in prefrontal cortex, hippocampus, striatum and cerebral cortex. In addition, complex II activity was increased by the same drug in hippocampus, striatum and cerebral cortex and complex IV activity in prefrontal cortex. Furthermore, chronic administration of nortriptyline increased complex II activity in hippocampus and striatum and complex IV activity in prefrontal cortex, striatum and cerebral cortex. Finally, chronic administration of venlafaxine increased complex II activity in hippocampus, striatum and cerebral cortex and complex IV activity in prefrontal cortex.
  
  
  CONCLUSIONS
  On the basis of the present findings, it is tempting to speculate that an increase in brain energy metabolism by the antidepressant paroxetine, nortriptyline and venlafaxine could play a role in the mechanism of action of these drugs. These data corroborate with other studies suggesting that some antidepressants modulate brain energy metabolism.
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Giselli
authors.initials: G
authors.lastname: Scaini
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Débora D
authors.initials: DD
authors.lastname: Maggi
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Bruna T
authors.initials: BT
authors.lastname: De-Nês
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Cinara L
authors.initials: CL
authors.lastname: Gonçalves
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Gabriela K
authors.initials: GK
authors.lastname: Ferreira
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Brena P
authors.initials: BP
authors.lastname: Teodorak
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Gisele D
authors.initials: GD
authors.lastname: Bez
authors.affiliation: Programa de Pós-graduação em Ciências da Saúde, Universidade do Sul de Santa Catarina, Tubarão, SC, Brazil.
authors.forename: Gustavo C
authors.initials: GC
authors.lastname: Ferreira
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Patricia F
authors.initials: PF
authors.lastname: Schuck
authors.affiliation: Instituto Nacional de Ciência e Tecnologia Translacional em Medicina.
authors.forename: João
authors.initials: J
authors.lastname: Quevedo
authors.affiliation: Laboratório de Fisiopatologia Experimental, Programa de Pós-graduação em Ciências da Saúde, Universidade do Extremo Sul Catarinense, Criciúma, SC, Brazil.
authors.forename: Emilio L
authors.initials: EL
authors.lastname: Streck