A1 rather than A2A adenosine receptor as a possible target of Guanosine effects on mitochondrial dysfunction following Traumatic Brain Injury in rats.

Affiliation

Laboratory of Exercise Biochemistry, Center for Physical Education and Sports, Federal University of Santa Maria, Santa Maria, RS, Brazil. Electronic address: [Email]

Abstract

Traumatic brain injury (TBI) represents one of the leading causes of death worldwide. Its pathophysiology involves several neurochemical events including mitochondrial dysfunction. Since mitochondrial respiration plays a key role in cell survival, pharmacological interventions targeting mitochondrial function have been highlighted as a powerful tool against the neurodegenerative process triggered by TBI. Guanosine (GUO), a neuroprotective molecule in different neurological disorders involving neurotoxicity, has shown protective properties after TBI, however its mechanism of action is not well understood in the central nervous system (CNS). Therefore, the aim of this study is to evaluate the possible target receptor involved in the protective GUO effects on TBI-induced mitochondrial dysfunction in the cerebral cortex of rats. Results show that a single dose of GUO (7.5 mg/kg) injected 40 min after a fluid percussion injury (FPI) protects against loss of mitochondrial membrane potential and increase of reactive oxygen species 8 h post-TBI. These effects were specifically blocked by a pretreatment (10 min after TBI) with an A1 adenosine receptor antagonist (DPCPX 1 mg/kg). In contrast, pretreatment with an A2A adenosine receptor antagonist (SCH 58261 0.05 mg/kg) did not alter GUO effects. These findings suggest that acute GUO neuroprotection following TBI involves the modulation of the adenosinergic system, especially A1 adenosine receptor.

Keywords

Adenosinergic system,Fluid percussion injury,Mitochondrial membrane potential,Purinergic nucleoside,Reactive oxygen species,