Stelfa 2018 MiP2018
R-phenibut ((3R)-phenyl-4-aminobutyric acid) is a CNS active drug, weak agonist of GABA-B receptors and ligand of α2-δ subunit of voltage-dependent calcium channels, and is clinically used due to its anxiolytic and nootropic effects. Our recent studies show that R-phenibut possesses neuroprotective activity in experimental models of stroke and traumatic brain injury. The preservation of mitochondrial function is essential for normal brain functioning and favourable neurological outcomes after cerebral ischemia. The aim of the present study was to evaluate the effects of R-phenibut on mitochondrial functionality in in vitro model of anoxia-reoxygenation.
The acute effects of R-phenibut on anoxia-reoxygenation-induced mitochondrial damage were studied using Wistar rat brain homogenate. The respiration measurements with simultaneous H2O2/O flux detection were performed in MiR05Cr buffer solution using high-resolution respirometry (Oroboros Instruments, Innsbruck, Austria) as described previously . To induce anoxia, respiration of sample was stimulated by the addition of succinate with rotenone and ADP and preparation was left to consume all O2 in respiratory chamber (within 10-20 min), thereby reaching an anoxic state. After 30 min of anoxia, vehicle or R-phenibut at a concentration of 0.5 µg/mlwas added and O2 was reintroduced to the chamber by opening the chamber to achieve reoxygenation. After 8 min, the chamber was closed and O2 flux monitored for additional 2 min. The effect of anoxia-reoxygenation on mitochondrial function was calculated as a difference between values at normoxia and after anoxia-reoxygenation expressed as percentage of normoxic values.
Anoxia-reoxygenation induced a significant 1.5-fold increase in H2O2 production rate and H2O2/O flux ratio in the vehicle control group. The addition of R-phenibut at a concentration of 0.5 µg/ml significantly decreased H2O2 production rate and H2O2/O flux ratio after anoxia-reoxygenation. Overall, addition of R-phenibut prevented anoxia-reoxygenation-induced increase in H2O2 production and H2O2/O ratio by 45% and 38%, respectively.
In conclusion, R-phenibut protects brain mitochondria from anoxia-reoxygenation-induced damage, and this mechanism might underlie the anti-ischemic effects of R-phenibut in stroke and traumatic brain injury models.
Labels: MiParea: Respiration, Pharmacology;toxicology
Stress:Ischemia-reperfusion, Oxidative stress;RONS Organism: Rat Tissue;cell: Nervous system Preparation: Homogenate
Coupling state: OXPHOS Pathway: S HRR: Oxygraph-2k, O2k-Fluorometer
- Stelfa (Vikmane) G(1,2), Makrecka-Kuka M(1), Zvejniece L(1), Svalbe B(1), Vavers E(1,3), Kupats E(1,3), Dambrova M(1,3)
- Latvian Inst Organic Synthesis
- Latvia Univ Life Sciences Technologies
- Riga Stradins Univ, Riga, Latvia. - [email protected]
- Makrecka-Kuka M, Krumschnabel G, Gnaiger E (2015) High-resolution respirometry for simultaneous measurement of oxygen and hydrogen peroxide fluxes in permeabilized cells, tissue homogenate and isolated mitochondria. Biomolecules 5:1319-38.