Bioenergetic signature of Synaptic mitochondria

Abstract

Synaptic transmission is the most energy-demanding processes in the brain and here we show that mitochondria have developed specific properties to efficiently support neurotransmission. It is a known fact that mitochondria at synapses need to be able to deal with a dynamic range of energetic needs overtime and to adapt between resting and high stimulation conditions. However, how mitochondria are adjusting to this requirement was not yet clear. Here, we show that synaptic mitochondria have a distinct bioenergetic profile presenting a stronger ability to respond to respiratory stimulus. These features are explained by a dichotomic Complex I activity pattern where synaptic mitochondria present a decreased enzymatic activity of individual Complex I, yet mitochondria at synapse present a dramatically enhanced Complex I+III combined activity. These bioenergetics features may endow synaptic mitochondria with the necessary mechanisms to adapt to the flexible bioenergetic environment present at synapses.